Chronic Obstructive Pulmonary Disease (COPD)

Clinical Snapshot

Chronic obstructive pulmonary disease (COPD) is a common, preventable, and treatable disease characterized by persistent respiratory symptoms and progressive, largely irreversible airflow limitation, caused by chronic inflammation of the airways and lung parenchyma that is most often driven by cigarette smoking.^[1] The cardinal symptoms are breathlessness, chronic cough, and sputum production; the hallmark functional finding is a post-bronchodilator FEV1/FVC ratio below the lower limit of normal (or below 0.7), confirming fixed airflow obstruction that bronchodilators improve but do not normalize.^[2]

COPD behaves as a systemic disease: breathlessness drives patients to restrict physical activity, which triggers a downward spiral of deconditioning, worsening dyspnea, and further inactivity. Because this cycle — not the spirometric abnormality alone — drives much of the disability in COPD, smoking cessation and optimal bronchodilation are the two interventions that most directly interrupt it, alongside pulmonary rehabilitation to reverse deconditioning that has already occurred.

Recognize the Condition

Typical presentation

Progressive exertional dyspnea is the dominant symptom — insidious at onset, often minimized or attributed to aging or deconditioning by the patient, and progressive over years. Chronic cough (often productive, sometimes intermittent and non-productive) and regular sputum production frequently precede or accompany the dyspnea. Patients typically restrict physical activity to avoid breathlessness, which itself becomes a further source of functional decline.

Assessing symptom severity

Two validated tools quantify the impact of breathlessness and overall symptom burden, and both directly drive the GOLD ABE treatment groups (see Choose Initial Treatment).

Grade	Description
0	I only get breathless with strenuous exercise.
1	I get short of breath when hurrying on the level or walking up a slight hill.
2	I walk slower than people of the same age on the level because of breathlessness, or I have to stop for breath when walking at my own pace on the level.
3	I stop for breath after walking about 100 metres or after a few minutes on the level.
4	I am too breathless to leave the house, or I am breathless when dressing or undressing.

Modified Medical Research Council (mMRC) dyspnea scale — the patient selects the single grade that best describes their breathlessness.^[3]

The COPD Assessment Test (CAT) is a complementary 8-item patient-completed questionnaire (each item scored 0-5, total 0-40) capturing a broader symptom burden than dyspnea alone — cough, phlegm, chest tightness, breathlessness on exertion, activity limitation, confidence leaving home, sleep, and energy.^[4] A CAT score of 10 or more, or an mMRC grade of 2 or more, defines "more symptoms" for GOLD group assignment.

Physical examination

Physical examination is relatively insensitive for diagnosis, especially in early disease — wheeze and signs of dyspnea may be the only findings. Signs of hyperinflation, hypoxemia, and pulmonary hypertension appear only in more advanced disease and should not be relied on to detect COPD early.

Risk Factors

Cigarette smoking — the dominant risk factor; risk is proportional to cumulative pack-year exposure.
Heavy occupational exposure to dusts, chemicals, or fumes.
Indoor and outdoor air pollution, including biomass fuel exposure.
Alpha1-antitrypsin deficiency — an under-recognized genetic cause, associated with emphysema, liver disease, and panniculitis.
Genetic variation more broadly — research suggests genetic factors influence both the presentation and severity of COPD independent of smoking history.
Recurrent lower respiratory tract infections, particularly in childhood, which can impair lung development and lower peak attained lung function.
A history of asthma — chronic, poorly controlled asthma is itself a risk factor for later fixed airflow obstruction.
Older age.

Red Flags & Refer

Escalate to emergency assessment or urgent specialist referral for any of the following:

Signs of acute respiratory failure — severe dyspnea at rest, accessory muscle use, paradoxical abdominal wall movement, inability to speak in full sentences, new or worsening confusion or drowsiness, or central cyanosis.
Oxygen saturation below 90%, or pulse oximetry/arterial blood gas criteria suggesting respiratory failure (FEV1 <1 L or <40% predicted, SaO2 <92%, or clinical signs of respiratory failure or right heart failure) — obtain arterial blood gases and escalate immediately.^[2]
Hemodynamic instability, new arrhythmia, or signs of cor pulmonale (peripheral edema, elevated jugular venous pressure) with worsening respiratory symptoms.
An exacerbation not responding to initial bronchodilator, corticosteroid, and (if indicated) antibiotic therapy within 24-72 hours.
Symptoms or findings suggesting an alternative or coexisting diagnosis masquerading as an exacerbation — chest pain suggesting acute coronary syndrome or pneumothorax, hemoptysis, unexplained fever, or signs of pneumonia, pulmonary embolism, or acute heart failure.
Unexplained or accelerating weight loss, or new hemoptysis — investigate for lung cancer rather than attributing it to COPD alone.
Suspected alpha1-antitrypsin deficiency (COPD onset before age 45, minimal smoking history, or a strong family history) — refer for testing and specialist management.^[5]
Severe, refractory disease being considered for long-term oxygen therapy, non-invasive ventilation, lung volume reduction, or transplant assessment — refer to a specialist COPD/respirology program.

Assessment & Diagnosis

Differentiating COPD from asthma

COPD and asthma are distinct disorders that are sometimes confused on initial presentation, although they may share treatable traits (e.g., eosinophilic inflammation, partial reversibility) and can coexist in the same patient.^[1]

Feature	COPD	Asthma
Typical age of onset	Usually after age 40	Often childhood or early adulthood, but can begin at any age
Smoking history	Strongly associated; usually a significant pack-year history	Not a prerequisite
Symptom pattern	Slowly progressive, persistent exertional dyspnea	Variable and often episodic, with symptom-free intervals
Diurnal/day-to-day variability	Minimal	Often pronounced, characteristically worse at night or early morning
Atopy/allergy history	Not typical	Common — personal or family history of allergy, rhinitis, or eczema
Airflow obstruction	Persistent; only partially reversible with a bronchodilator	Typically fully or near-fully reversible with a bronchodilator
Diagnostic spirometry	Post-bronchodilator FEV1/FVC below 0.7 (or below the lower limit of normal) required	Variable airflow obstruction; spirometry may normalize between exacerbations
Disease course	Progressive decline in lung function over time	Usually stable if well controlled; less inherent progressive decline
Role of inhaled corticosteroids	Adjunctive, reserved for specific higher-risk/eosinophilic phenotypes — never used alone	Central controller therapy in essentially all persistent disease

History

Characterize dyspnea onset, pattern, and severity (mMRC/CAT), chronic cough, and sputum production/volume/colour.
Quantify smoking history in pack-years, and ask about occupational dust/chemical exposure and biomass fuel exposure.
Ask specifically about alpha1-antitrypsin deficiency risk factors (early-onset disease, minimal smoking history, family history).
Screen for comorbidities that share risk factors with, or worsen the course of, COPD: cardiovascular disease, osteoporosis, skeletal muscle dysfunction, pulmonary embolism, secondary polycythemia, depression/anxiety, malnutrition, pneumonia, malignancy, and metabolic syndrome.
Obtain a full exacerbation history — hospitalizations, emergency visits, and courses of oral corticosteroids or antibiotics in the past year — since this directly determines GOLD group assignment (see Choose Initial Treatment).
Assess impact on daily function and the social supports available.

Physical examination

Relatively insensitive for diagnosis, particularly early in disease; wheeze and signs of dyspnea may be the only findings. Signs of hyperinflation, hypoxemia, and pulmonary hypertension are late findings.

Spirometry — the gold standard for diagnosis

A post-bronchodilator FEV1/FVC ratio below 0.7 confirms persistent airflow limitation and is required to establish the diagnosis; a ratio below the lower limit of normal (LLN) is the more accurate criterion and avoids over-diagnosing COPD in older adults, in whom a fixed 0.7 cut-off can be falsely positive — LLN is the preferred measurement in Canada.^[2] A significant bronchodilator response — an increase in FEV1 of at least 12% and at least 200 mL after inhaled salbutamol — supports reversibility but does not exclude COPD, and its presence or absence should never be used alone to distinguish COPD from asthma.

Pre-bronchodilator spirometry can only be used to exclude a diagnosis of COPD, not to confirm one — a normal pre-bronchodilator FEV1/FVC rules COPD out, but an abnormal pre-bronchodilator result requires post-bronchodilator testing before the diagnosis can be made.

GOLD grade	Severity	Post-bronchodilator FEV1 (% predicted)
GOLD 1	Mild	≥80%
GOLD 2	Moderate	50-79%
GOLD 3	Severe	30-49%
GOLD 4	Very severe	<30%

Spirometric grade describes the severity of airflow obstruction but no longer drives initial treatment selection on its own — see the GOLD ABE assessment in Choose Initial Treatment.

Additional investigations

CBC — screens for polycythemia (a marker of chronic hypoxia) or anemia, either of which can worsen dyspnea.
Chest x-ray — to exclude alternative diagnoses (lung cancer, bronchiectasis, tuberculosis), not to diagnose COPD itself.
Pulse oximetry, with arterial blood gases if FEV1 <1 L or <40% predicted, SaO2 <92%, or there are clinical signs of respiratory failure or right heart failure.
Alpha1-antitrypsin level in any patient under 65 years of age presenting with COPD, with fewer than 20 pack-years of smoking history, or with a strong family history of COPD.^[5]
Blood eosinophil count (via CBC) — not needed for diagnosis, but essential once COPD is confirmed, since it is the key biomarker guiding whether an inhaled corticosteroid belongs in the regimen (see Choose Initial Treatment).
Lung volumes, carbon monoxide diffusing capacity, and CT imaging are reserved for a marked discordance between the degree of airflow obstruction and perceived symptoms, or when surgical/interventional therapy is being considered — neither is a routine diagnostic test for uncomplicated COPD.

Treatment Targets

Prevent disease progression.
Decrease or eliminate breathlessness and other respiratory symptoms through optimal bronchodilation.
Improve exercise tolerance and reverse activity-limitation-driven deconditioning.
Reduce the frequency and severity of exacerbations.
Improve health-related quality of life.
Recognize and treat COPD comorbidities — cardiovascular disease, depression/anxiety, osteoporosis, and smoking-related malignancies.
Reduce impairment and disability.
Reduce mortality.

Choose Initial Treatment

The GOLD ABE assessment (guides initial pharmacotherapy)

Once COPD is confirmed by spirometry, initial drug therapy is chosen using the number and severity of exacerbations in the past year together with current symptom burden (mMRC or CAT) — not spirometric grade alone.^[1]

The GOLD ABE groups

Group A

0 or 1 moderate exacerbation in the past year not leading to hospital admission, and mMRC 0-1 or CAT <10.

Group B

0 or 1 moderate exacerbation in the past year not leading to hospital admission, and mMRC ≥2 or CAT ≥10.

Group E

1 or more moderate exacerbations in the past year, or 1 or more exacerbations leading to hospital admission — regardless of symptom score. The 2026 GOLD report lowered this threshold: previously 2 or more moderate exacerbations were required to reach Group E, but even a single moderate exacerbation before starting maintenance therapy has been shown to meaningfully increase the risk of subsequent exacerbations.^[1]

Direct treatment rule

Group A offer a bronchodilator based on its effect on breathlessness — either short- or long-acting. A long-acting bronchodilator is preferred where available and affordable, except in patients with only occasional breathlessness, for whom an as-needed short-acting bronchodilator alone is reasonable.

Group B start combination LABA + LAMA therapy as initial treatment — superior to LAMA monotherapy in patients with a CAT ≥10, provided there are no issues with availability, cost, or side effects.^[6]

Group B, if LABA+LAMA is not appropriate either a LABA or a LAMA alone is a reasonable initial choice; there is no evidence favouring one class over the other for initial symptom relief, so let the patient's perceived symptom relief guide the choice.

Group E start combination LABA + LAMA therapy as initial treatment.

Group E with blood eosinophils ≥300 cells/µL consider starting LABA + LAMA + ICS (triple therapy) instead of LABA+LAMA alone — the effect of ICS on exacerbation prevention correlates with blood eosinophil count (see Drug Tables).

Do not start LABA+ICS without a LAMA — dual ICS/LABA therapy is not encouraged in COPD; where an ICS is indicated, LABA+LAMA+ICS triple therapy is preferred over LABA+ICS.^[1]

Every patient, in every group, should also be prescribed an as-needed short-acting bronchodilator (SABA, with or without a SAMA) for immediate symptom relief.

If a patient with COPD also has a concurrent diagnosis of asthma, treat according to asthma pharmacotherapy principles — an ICS is mandatory in that situation regardless of GOLD group.

Non-Pharmacologic Treatment

Smoking cessation — the single highest-impact intervention

Advise and support cessation at every visit; this is the only intervention proven to slow the rate of lung function decline and reduce mortality in COPD, and its benefit exceeds that of any pharmacologic option.^[2] Sustained cessation (10 or more years) is associated with a progressively lower risk of acute exacerbations, proportional to smoke-free time. Offer pharmacotherapy (nicotine replacement therapy or varenicline — see Pharmacologic Treatment Options; bupropion is a further recognized alternative agent) alongside behavioural counselling at every attempt — do not rely on counselling or willpower alone.

Pulmonary rehabilitation, exercise, and education

Pulmonary rehabilitation is a comprehensive, patient-tailored intervention combining exercise training, education, and behaviour change, delivered by a multidisciplinary team (respiratory therapists, Certified Respiratory Educators, pharmacists, and other allied health professionals). Refer symptomatic patients early — benefit is seen across all stages of COPD severity, not only advanced disease.^[2] After an acute exacerbation, initiate or resume pulmonary rehabilitation within 4 weeks to reduce the risk of further exacerbations.

Encourage regular physical activity and reinforce pursed-lip breathing technique at every visit — patients with lower activity levels after hospital discharge are more likely to be readmitted, and deconditioning itself limits the effectiveness of pharmacologic treatment.

Vaccination

Ensure every patient with COPD is up to date on all age-appropriate immunizations, since respiratory infection is a major driver of exacerbations.^[7]

Influenza: annual vaccination with an inactivated (killed) vaccine, given early in the fall — reduces exacerbations, hospitalization, and death in COPD. Avoid the live-attenuated intranasal vaccine in chronic lung disease.
Pneumococcal: one dose of a pneumococcal conjugate vaccine (Pneu-C-20 or Pneu-C-21) for all adults with COPD aged 50 and older, regardless of prior vaccination with an earlier pneumococcal vaccine (Pneu-C-13, Pneu-C-15, or Pneu-P-23).^[7]
Respiratory syncytial virus (RSV): strongly recommended for all adults 75 and older, and for adults 65-74 with an increased risk of severe RSV disease (which includes COPD). Strongly recommended regardless of age (18 and older) for anyone on home or chronic oxygen therapy — a group at particularly high risk of severe RSV disease.^[8]
Tdap (tetanus, diphtheria, acellular pertussis): recommended for patients with COPD not vaccinated against pertussis in adolescence, given increased pertussis risk in chronic lung disease.
Shingles (recombinant zoster vaccine): routine vaccination recommended per standard age-based adult immunization schedules.
COVID-19: keep up to date with vaccination per current national recommendations.

Written action plan and self-management

Provide a written COPD action plan describing early warning signs of an exacerbation and the specific steps to take — but always combine it with structured education and case management; an action plan alone, without this support, has not been shown to reduce exacerbations or urgent care use.

Inhaler technique and device selection

Review inhaler technique at every visit — poor technique is common, often goes uncorrected, and directly undermines drug delivery regardless of which agent is prescribed. Choose the delivery device (pMDI with or without a spacer, dry powder inhaler, soft mist inhaler, or nebulizer) based on the patient's ability to use it correctly, consistently, and affordably; reserve nebulizers for patients who remain symptomatic despite maximal treatment with a correctly-used handheld device. Where possible, use one inhaler device type for all of a patient's COPD medications to simplify technique and improve adherence.

Other measures

Minimize or eliminate exposure to air pollution and occupational dusts/chemicals.
Address nutrition — both underweight and obese patients with COPD have worse outcomes; involve dietary support where indicated.
Oscillating positive expiratory pressure (OCEP) devices (e.g., Aerobika) have limited supporting evidence to date and are not yet incorporated into Canadian or GOLD guideline recommendations — larger studies are needed before routine use can be recommended.
In selected patients with advanced emphysema refractory to optimized medical therapy, surgical or bronchoscopic lung volume reduction, or lung transplantation may be appropriate — refer to a specialist COPD program for assessment.
Palliative care approaches are effective for symptom control in advanced COPD and should be introduced alongside, not instead of, active disease management.

Pharmacologic Treatment Options

Drug / intervention	Role	Dose / use	Important adverse effects	Teaching points
Salbutamol Preferred	Rescue SABA — every patient, every GOLD group	100 mcg/puff, 1-2 puffs inhaled QID PRN, max 8 puffs (800 mcg)/day	Tremor, tachycardia, hypokalemia	Prescribe to every patient regardless of GOLD group for as-needed symptom relief.
Ipratropium Alternative	Rescue SAMA alternative/adjunct	20 mcg/puff, 2-4 puffs inhaled Q6-8H PRN, max 12 puffs/day	Dry mouth, urinary retention	Slower onset than a SABA; limited role as monotherapy given inferior efficacy to a LAMA.
Tiotropium Preferred	Group B/E — first-line LAMA	18 mcg capsule inhaled once daily (DPI), or 2 inhalations (5 mcg total) once daily (SMI)	Dry mouth, urinary retention	Reduces exacerbations and hospitalizations; no increased cardiovascular risk found on formal safety review.
Umeclidinium/Vilanterol Preferred	Group B/E — preferred initial LAMA+LABA	62.5/25 mcg, 1 inhalation via DPI once daily	Dry mouth, tremor, tachycardia	Preferred over LABA+ICS when starting combination bronchodilator therapy.
Budesonide/Glycopyrronium/Formoterol Special situation	Triple therapy — Group E with eosinophils ≥300 cells/µL, or exacerbating on LABA+LAMA with eosinophils ≥100 cells/µL	2 inhalations via pMDI BID (morning and evening)	Oropharyngeal candidiasis, dry mouth, tremor, pneumonia risk	Use a single-inhaler triple product — never combine with a separate LABA or LAMA (duplicate class).
Roflumilast Special situation	Add-on for severe COPD with chronic bronchitis and frequent exacerbations	500 mcg PO once daily	Nausea, diarrhea, weight loss, insomnia, depression	Avoid with a history of depression with suicidal ideation. Not a bronchodilator — does not treat acute symptoms.
Azithromycin (prophylactic) Special situation	Frequent exacerbator, non-smoker, despite optimal inhaled therapy	250 mg PO 3 times weekly (or 500 mg 3 times weekly), typically 3-12 months	GI upset, QTc prolongation, ototoxicity	Confirm baseline QTc and hearing; weigh antimicrobial resistance risk.
Dupilumab Special situation	Add-on biologic — eosinophils ≥300 cells/µL, inadequately controlled on triple therapy (or LABA+LAMA if ICS inappropriate)	300 mg SC every 2 weeks	Injection-site reaction, transient eosinophilia	Health Canada-approved for COPD (2025); preferred if a chronic bronchitis phenotype is present.
Mepolizumab Special situation	Add-on biologic — eosinophils ≥300 cells/µL, inadequately controlled on triple therapy	100 mg SC every 4 weeks	Injection-site reaction, headache	Health Canada-approved for COPD (2026); effective with or without a chronic bronchitis phenotype.
Prednisone Special situation	Acute moderate/severe exacerbation only — not maintenance	30-40 mg PO once daily for 5 days	Hyperglycemia, insomnia, GI upset	No role for chronic maintenance oral corticosteroid therapy. Tapering unnecessary for courses under 2 weeks.
Varenicline Preferred	Smoking-cessation pharmacotherapy	0.5 mg PO daily (days 1-3), then 0.5 mg BID (days 4-7), then 1 mg BID (day 8 onward) for 12 weeks	Nausea, vivid dreams, neuropsychiatric symptoms (monitor mood)	One of the most effective single smoking-cessation agents; start 1-2 weeks before the planned quit date.
Nicotine Replacement Therapy Preferred	Smoking-cessation pharmacotherapy	Patch tapered 21→14→7 mg/24h over 6-10 weeks ± gum/lozenge (2 or 4 mg) PRN for breakthrough cravings	Local skin irritation (patch); mouth/throat irritation (gum/lozenge)	Combining a patch with an as-needed gum or lozenge is more effective than either form alone.

Special Populations

Pregnancy

Smoking cessation is the single most important intervention in a pregnant patient with COPD, or any pregnant smoker — pursue it more urgently than in the non-pregnant setting, using behavioural counselling first-line and NRT if counselling alone is insufficient, since the risk of continued smoking outweighs the risk of NRT itself. Inhaled short- and long-acting bronchodilators (SABA, SAMA, LABA, LAMA) are generally continued through pregnancy when needed for symptom control, since undertreated maternal hypoxemia poses a greater fetal risk than these agents. Apply the same eosinophil-guided principles for ICS as in the non-pregnant patient — do not withhold a clinically indicated ICS because of pregnancy. Data for roflumilast and theophylline in pregnancy are limited — avoid unless the treating specialist judges the benefit clearly outweighs the uncertainty. Varenicline has limited pregnancy safety data; NRT is generally the preferred pharmacotherapy for smoking cessation in pregnancy when counselling alone fails.

Breastfeeding

Inhaled bronchodilators and inhaled corticosteroids are compatible with breastfeeding given minimal systemic absorption. Theophylline passes into breast milk in clinically relevant amounts — monitor the infant for irritability or feeding difficulty if the mother requires theophylline. NRT is compatible with breastfeeding; take doses after a feed rather than immediately before when practical.

Pediatrics

COPD is fundamentally an adult-onset, cumulative-exposure disease — it is not diagnosed or treated in children, and none of the maintenance pharmacotherapy in this chapter has an established pediatric COPD dose. A child or adolescent with unexplained fixed airflow obstruction should be worked up for an alternative cause (e.g., cystic fibrosis, bronchopulmonary dysplasia, early-onset alpha1-antitrypsin deficiency) rather than treated as COPD.

Older adults

The majority of patients with COPD are older adults. Assess cognitive status and manual dexterity when selecting an inhaler device, since correct technique is essential to drug delivery regardless of severity. Review the cumulative anticholinergic burden when a LAMA is combined with other anticholinergic medications the patient may already be taking for unrelated conditions (e.g., overactive bladder, some antidepressants). No dose adjustment of tiotropium or umeclidinium/vilanterol is required specifically for age.

Renal impairment

Most inhaled LAMAs (tiotropium, umeclidinium, glycopyrronium) require no dose adjustment in mild-moderate renal impairment, but should be used with caution and closely monitored for anticholinergic side effects in severe renal impairment, since renal clearance contributes meaningfully to their elimination. Sulfamethoxazole/trimethoprim and the fluoroquinolones used for exacerbations require renal dose adjustment. Theophylline itself is not renally cleared, but many drugs that interact with it are.

Hepatic impairment

Theophylline clearance is reduced in hepatic impairment — use lower starting doses and closely monitor serum levels. Roflumilast is not recommended in moderate-to-severe hepatic impairment (Child-Pugh B or C).

Alpha1-antitrypsin deficiency

A distinct COPD subpopulation requiring specialist confirmation and consideration of intravenous augmentation therapy in addition to standard COPD pharmacotherapy — refer to a specialist program once a low alpha1-antitrypsin level is confirmed.^[5]

Monitoring & Follow-Up

Individualize the follow-up interval — more frequent in patients with more severe disease, longer in milder disease.
Reassess symptom burden (mMRC or CAT) and exacerbation frequency at every visit.
Repeat spirometry at least annually.
Check inhaler technique and adherence at every visit — one of the highest-yield things a pharmacist can do at each encounter.
Reassess smoking status and readiness to quit at every visit, regardless of how many prior attempts have failed.
Screen for and actively manage comorbidities (cardiovascular disease, osteoporosis, depression/anxiety, nutrition/weight) — these influence health status and mortality independently of airflow obstruction severity.
Confirm vaccination status is current.
For a patient on long-term oxygen therapy, non-invasive ventilation, or awaiting interventional/surgical assessment, coordinate structured specialist follow-up alongside routine primary/pharmacy care.
Update the written action plan at each visit and confirm the patient knows when and how to use it.

Treatment Failure / Next Step

Before escalating any therapy, confirm inhaler technique is correct, confirm adherence, and screen for comorbidities that could be mimicking or worsening symptoms (e.g., heart failure, anxiety, deconditioning).
Identify the predominant treatable trait driving inadequate control — persistent dyspnea/activity limitation, or ongoing exacerbations — since the escalation pathway differs for each; if both are present, follow the exacerbation pathway.^[1]
Dyspnea pathway: if breathless on bronchodilator monotherapy, add a second long-acting bronchodilator class to reach LABA+LAMA. If dyspnea persists on LABA+LAMA despite confirmed technique and adherence, consider switching inhaler device or molecule within the same class, escalate non-pharmacologic therapy (pulmonary rehabilitation), and consider adding ensifentrine — a novel inhaled PDE3/4 inhibitor — where accessible; it is not currently available in Canada. Investigate and treat non-COPD causes of dyspnea (cardiac, anemia, deconditioning, anxiety) before escalating COPD-specific therapy further.
Exacerbation pathway: if exacerbating on bronchodilator monotherapy, escalate to LABA+LAMA. If a moderate or severe exacerbation occurs on LABA+LAMA, escalate to LABA+LAMA+ICS triple therapy — a beneficial ICS response is more likely with blood eosinophils ≥100 cells/µL, with greater benefit at higher counts.
If exacerbations continue on LABA+LAMA with blood eosinophils under 100 cells/µL, consider adding azithromycin prophylaxis (in patients who are not currently smoking) or roflumilast (in patients with FEV1 <50% predicted, chronic bronchitis symptoms, and a prior exacerbation requiring hospitalization).
If exacerbations continue despite triple therapy, in patients with blood eosinophils ≥300 cells/µL, consider adding dupilumab (preferred if a chronic bronchitis phenotype is present) or mepolizumab (effective with or without a chronic bronchitis phenotype); azithromycin and roflumilast remain options per the criteria above regardless of eosinophil count.
Do not withdraw the ICS component from a patient stable on triple therapy unless it was started inappropriately, there has been no response, or the patient has significant side effects or recurrent pneumonia — de-escalation is more likely to be followed by exacerbations if blood eosinophils remain ≥300 cells/µL.
After any exacerbation, review and optimize the entire management plan — inhaler technique, adherence, non-pharmacologic measures, and vaccination status — and refer to pulmonary rehabilitation within 4 weeks.

Common Errors to Avoid

Diagnosing COPD from symptoms or a chest x-ray alone, without confirmatory post-bronchodilator spirometry.
Using a pre-bronchodilator-only spirometry result to confirm COPD — it can only be used to exclude the diagnosis, not establish it.
Starting or continuing ICS/LABA dual therapy without a LAMA, or ICS monotherapy — neither is recommended in COPD.
Prescribing antibiotics for a mild exacerbation without purulent sputum or the other cardinal symptoms that justify their use.
Treating pharmacotherapy as sufficient on its own and skipping smoking-cessation counselling at follow-up visits.
Continuing oral corticosteroids beyond the acute exacerbation course — there is no role for chronic maintenance oral corticosteroid therapy in COPD.
Unnecessarily tapering a short (under 2-week) oral corticosteroid course for an exacerbation.
Never checking or correcting inhaler technique at follow-up.
Prescribing duplicate therapy from the same drug class (e.g., a separate LAMA product alongside a LAMA/LABA combination inhaler).
Missing alpha1-antitrypsin deficiency testing in a younger patient with COPD and a minimal smoking history.
Withdrawing the ICS component from a triple-therapy patient with blood eosinophils ≥300 cells/µL without recognizing the elevated risk of subsequent exacerbations.
Over-titrating supplemental oxygen in a hypoventilating (hypercapnic) patient without monitoring for worsening hypercarbic hypoxia.

Clinical Decision Algorithm

Diagnosis and GOLD ABE-based initial treatment

Dyspnea, chronic cough, sputum production, and/or risk factor exposure (smoking, occupational, biomass fuel)

Post-bronchodilator spirometry

FEV1/FVC ≥0.7 (or ≥LLN)

COPD not confirmed — reassess for asthma or an alternative diagnosis

FEV1/FVC under 0.7 (or <LLN)

COPD confirmed — assess symptom burden (mMRC/CAT) and exacerbation history from the past year

Group A: 0-1 moderate exacerbation, mMRC 0-1/CATunder 10

Short- or long-acting bronchodilator, based on symptom relief

Group B: 0-1 moderate exacerbation, mMRC≥2/CAT≥10

Start LABA + LAMA

Group E: ≥1 moderate exacerbation, or ≥1 hospitalization

Start LABA + LAMA

Blood eosinophils ≥300 cells/µL? Consider LABA+LAMA+ICS as initial therapy instead

Follow-up escalation: dyspnea vs. exacerbation pathway

Patient already on maintenance therapy, response inadequate

Confirm inhaler technique and adherence; screen for interfering comorbidities

Persistent dyspnea/activity limitation

On bronchodilator monotherapy: add a second class to reach LABA+LAMA

Still breathless on LABA+LAMA: switch device/molecule, escalate pulmonary rehabilitation, consider ensifentrine if accessible (not yet available in Canada)

Ongoing exacerbations (use this pathway if both traits are present)

On bronchodilator monotherapy: escalate to LABA+LAMA

Moderate/severe exacerbation on LABA+LAMA: escalate to LABA+LAMA+ICS (more likely to help if eosinophils ≥100 cells/µL)

Eosinophils under 100 cells/µL, still exacerbating on LABA+LAMA

Consider azithromycin (non-smokers) or roflumilast (FEV1under 50%, chronic bronchitis, prior hospitalization)

Still exacerbating on LABA+LAMA+ICS, eosinophils ≥300 cells/µL

Consider adding dupilumab or mepolizumab

ICS de-escalation being considered

Do not withdraw ICS unless inappropriate start, no response, or significant side effects/recurrent pneumonia — higher relapse risk if eosinophils ≥300 cells/µL

Acute exacerbation management

Sustained worsening of dyspnea, cough, and/or sputum over hours to days

Assess severity — symptom characteristics, vital signs, oxygen saturation, and signs of respiratory distress^[9]

Signs of respiratory failure, hemodynamic instability, or altered mental status

Manage as a medical emergency — arterial blood gases, high-flow oxygen/NIV as indicated, hospital-level care

No red flags — ambulatory management appropriate

Increase SABA ± SAMA dose/frequency

Moderate/severe exacerbation: add prednisone 30-40 mg PO daily x 5 days

2 or more of increased dyspnea, increased sputum volume, or increased sputum purulence: add a risk-stratified antibiotic (see Drug Tables)

Re-evaluate within 24-48 hours; escalate to hospital-level care if not improving

After recovery: review and optimize maintenance therapy, technique, and non-pharmacologic measures; refer to pulmonary rehabilitation within 4 weeks

Drug Tables

How to use this table: doses are adult doses and require patient-specific confirmation, including renal/hepatic adjustment. COPD is an adult-onset disease — pediatric dosing is not established for any agent in this table and none is included. Select any drug name to open its complete Pharmasist Drug Database page.

Short-acting bronchodilators

For as-needed symptom relief in every patient, regardless of GOLD group.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Salbutamol	pMDI: 100 mcg/puff, 1-2 puffs inhaled TID-QID PRN, max 8 puffs (800 mcg)/day DPI: 200 mcg/actuation, 1 actuation inhaled TID-QID PRN, max 800 mcg/day Nebules: 2.5-5 mg inhaled QID PRN	Tremor, nervousness, tachycardia, palpitations, hypokalemia	Additive hypokalemia with corticosteroids, diuretics, theophylline	First-line SABA; doses may be doubled or tripled under supervision for breakthrough symptoms.
Terbutaline	DPI: 0.5 mg/actuation, 1 actuation inhaled Q4-6H PRN, max 6 actuations/day	Tremor, nervousness, tachycardia, palpitations, hypokalemia	Additive hypokalemia with corticosteroids, diuretics, theophylline	Alternative SABA.
Ipratropium	pMDI: 20 mcg/puff, 2-4 puffs inhaled Q6-8H, up to 6-8 puffs if tolerated, max 12 puffs/day Nebules: 250-500 mcg inhaled TID-QID	Dry mouth, metallic taste, urinary retention; mydriasis/glaucoma if sprayed in the eye	Possible increased cardiovascular event risk in a dose-dependent manner	SAMA; slower onset but longer duration than a SABA. Limited role as monotherapy given inferior efficacy to a LAMA.
Ipratropium/Salbutamol	SMI: 20/100 mcg/actuation, 1 actuation inhaled QID, additional doses PRN, max 6 doses/day Nebules (UDV): 0.5/2.5 mg per 2.5 mL, 2.5 mL inhaled Q6H PRN	Dry mouth, metallic taste, tremor, tachycardia, hypokalemia	Possible increased cardiovascular event risk from the ipratropium component	Combination gives greater, more sustained bronchodilation than either drug alone, with a similar or lower side-effect incidence.

Long-acting bronchodilators — beta2-agonists (LABA)

Offered as monotherapy mainly when a LAMA cannot be tolerated or adherence with twice-daily dosing is a concern.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Formoterol	DPI: 6 or 12 mcg/actuation, 1 actuation inhaled Q12H, max 48 mcg/day	Tremor, nervousness, tachycardia, palpitations, hypokalemia	Avoid combining with another LABA-containing product	Rapid onset (under 3 minutes) in addition to 12-hour duration, unlike salmeterol.
Salmeterol	DPI: 50 mcg/blister, 1 blister inhaled BID	Tremor, nervousness, tachycardia, palpitations, hypokalemia	Avoid combining with another LABA-containing product	Slower onset (20-120 minutes) than formoterol.

Long-acting bronchodilators — muscarinic antagonists (LAMA)

First-line long-acting bronchodilator class for Group B/E — reduces exacerbations and hospitalizations across the class.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Tiotropium	DPI (HandiHaler): 18 mcg capsule inhaled once daily SMI (Respimat): 2 inhalations (5 mcg total) once daily	Dry mouth, metallic taste, urinary retention; mydriasis/glaucoma if sprayed in the eye	Caution with other anticholinergic medications (additive burden)	First-line LAMA. No increased cardiovascular risk found on formal safety review.
Glycopyrronium	DPI: 50 mcg capsule inhaled once daily	Dry mouth, metallic taste, urinary retention	Caution with other anticholinergic medications (additive burden)	Rapid onset of action; bronchodilation observed on day 1.
Aclidinium	DPI: 400 mcg/actuation, 1 actuation inhaled BID	Dry mouth, metallic taste, urinary retention	Caution with other anticholinergic medications (additive burden)	Twice-daily dosing; effects on lung function similar to tiotropium and glycopyrronium.
Umeclidinium	DPI: 62.5 mcg/actuation, 1 actuation inhaled once daily	Dry mouth, metallic taste, urinary retention	Caution with other anticholinergic medications (additive burden)	Reduces moderate exacerbations requiring oral steroids/antibiotics; reduces rescue inhaler use.

Combination LAMA/LABA

Preferred over ICS/LABA when starting combination bronchodilator therapy, for symptom control and exacerbation prevention alike.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Umeclidinium/Vilanterol	DPI: 62.5/25 mcg/actuation, 1 actuation inhaled once daily	Dry mouth, tremor, tachycardia	Caution with other anticholinergic medications	Preferred initial LAMA/LABA choice for Group B/E.
Tiotropium/Olodaterol	SMI: 2.5/2.5 mcg/actuation, 2 actuations inhaled once daily	Dry mouth, tremor, tachycardia	Caution with other anticholinergic medications	Olodaterol is only available in Canada as this combination, not as a standalone LABA.
Glycopyrronium/Indacaterol	DPI: 50/110 mcg/capsule, 1 capsule inhaled once daily	Dry mouth, tremor, tachycardia	Caution with other anticholinergic medications	Shown superior to ICS/LABA (fluticasone/salmeterol) for delaying time to first exacerbation and reducing exacerbation/pneumonia rates.
Aclidinium/Formoterol	DPI: 400/12 mcg/actuation, 1 actuation inhaled BID	Dry mouth, tremor, tachycardia	Caution with other anticholinergic medications	Twice-daily LAMA/LABA option.

Combination ICS/LABA

ICS/LABA dual therapy without a LAMA is not encouraged in COPD (see Choose Initial Treatment) — included here for reference and for patients already established on this combination.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Budesonide/Formoterol	DPI: 100/6 or 200/6 mcg/actuation, 2 actuations inhaled BID, max 8 actuations/day	Oropharyngeal candidiasis, hoarseness, skin bruising, cataracts, possible reduced bone mineral density; LABA effects (tremor, tachycardia)	Increased pneumonia risk versus LABA alone	Rinse mouth after use; use a spacer with a pMDI formulation to reduce oropharyngeal deposition. Budesonide-based regimens may carry a lower pneumonia risk than fluticasone-based ones, though this has not been directly compared in trials.
Fluticasone Propionate/Salmeterol	pMDI: 125/25 or 250/25 mcg/puff, 2 puffs inhaled BID DPI: 100/50, 250/50, or 500/50 mcg/actuation, 1 actuation inhaled BID	Oropharyngeal candidiasis, hoarseness, skin bruising, cataracts, possible reduced bone mineral density; LABA effects	Increased pneumonia risk versus LABA alone; fluticasone-based ICS may carry the highest pneumonia risk of the ICS options
Fluticasone Furoate/Vilanterol	DPI: 100/25 mcg/actuation, 1 actuation inhaled once daily	Oropharyngeal candidiasis, hoarseness, skin bruising, cataracts, possible reduced bone mineral density; LABA effects	Increased pneumonia risk versus LABA alone	Once-daily dosing.
Indacaterol/Mometasone Furoate	DPI: 80/150, 160/150, or 320/150 mcg/capsule, 1 capsule inhaled once daily	Oropharyngeal candidiasis, hoarseness, skin bruising, cataracts, possible reduced bone mineral density; LABA effects	Increased pneumonia risk versus LABA alone	Once-daily dosing.

Combination ICS/LAMA/LABA (triple therapy)

Reserve for Group E patients with blood eosinophils ≥300 cells/µL, or patients already on LABA+LAMA who continue to exacerbate with eosinophils ≥100 cells/µL. Use a single-inhaler triple therapy product rather than combining separate inhalers, since compliance with multi-inhaler triple therapy is consistently poor.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Budesonide/Glycopyrronium/Formoterol	pMDI: 182/8.2/5.8 mcg/puff, 2 puffs inhaled BID	Oropharyngeal candidiasis, dry mouth, tremor, pneumonia risk, possible reduced bone mineral density	Caution with other anticholinergic medications
Fluticasone Furoate/Umeclidinium/Vilanterol	DPI: 100/62.5/25 mcg/actuation, 1 actuation inhaled once daily	Oropharyngeal candidiasis, dry mouth, tremor, pneumonia risk, possible reduced bone mineral density	Caution with other anticholinergic medications	The 100/62.5/25 mcg strength is used for COPD; the 200/62.5/25 mcg strength is for asthma only.

Phosphodiesterase-4 (PDE4) inhibitor

Drug	Dosage	Adverse effects	Drug interactions	Comments
Roflumilast	Adults: 500 mcg PO once daily	Nausea, vomiting, diarrhea, decreased appetite/weight, headache, insomnia, anxiety, depression	Strong CYP450 inducers (carbamazepine, phenobarbital, phenytoin, rifampin) reduce roflumilast's effect and are not recommended together	Add-on for severe COPD with chronic bronchitis and a history of frequent exacerbations, on top of bronchodilator therapy. Avoid with a history of depression with suicidal ideation. Not a bronchodilator — does not treat acute symptoms.

Methylxanthine

Reserve for severe symptoms despite optimized triple therapy; consult a specialist at this stage of disease. Narrow therapeutic index.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Theophylline	Initial: 200-300 mg PO BID Titration: increase by 50-100 mg Q12H at approximately 3-day intervals, guided by serum levels and side effects	Nausea, vomiting, abdominal cramps, headache, nervousness, tremor, insomnia, tachycardia	Levels decreased by alcohol, carbamazepine, phenobarbital, phenytoin, rifampin, and tobacco smoking; increased by amiodarone, cimetidine, ciprofloxacin, clarithromycin, erythromycin, fluvoxamine, isoniazid, mexiletine, verapamil	Monitor serum levels and adjust to the low therapeutic range (55-85 micromol/L). Levels can double if the patient stops smoking — reassess dosing at every quit attempt.

Mucolytic

Drug	Dosage	Adverse effects	Drug interactions	Comments
Acetylcysteine (N-acetylcysteine)	Adults: 600 mg PO BID	Nausea, vomiting, stomatitis, rhinorrhea	May enhance the vasodilating effect of nitroglycerin	Consider in moderate-severe COPD with 2 or more exacerbations in the previous 2 years. The injectable solution is given orally, usually diluted in a cola beverage to reduce nausea.

Prophylactic macrolide

For patients with moderate-severe COPD who have had 1 or more moderate or severe exacerbations in the past year despite optimal inhaled therapy. Confirm baseline QTc and hearing; weigh antimicrobial resistance risk; ideal duration has not been established.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Azithromycin (prophylactic)	Adults: 250 mg PO 3 times weekly (or 500 mg PO 3 times weekly), typically 3-12 months	GI upset, QTc prolongation, ototoxicity/hearing loss with prolonged use	Contraindicated with pimozide; caution with other QTc-prolonging drugs; may increase digoxin and warfarin effect	Benefit has not been shown in patients who continue to smoke.

Biologics (add-on for eosinophilic COPD)

Reserve for patients inadequately controlled on optimal inhaled triple therapy (or LABA+LAMA if ICS is not appropriate) with blood eosinophils ≥300 cells/µL.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Dupilumab	Adults: 300 mg SC every 2 weeks	Injection-site reaction, transient eosinophilia, conjunctivitis (less common in COPD than in atopic dermatitis)	None significant	Health Canada-approved for COPD. Preferred if a chronic bronchitis phenotype (chronic cough and sputum) is present.
Mepolizumab	Adults: 100 mg SC every 4 weeks	Injection-site reaction, headache	None significant	Health Canada-approved for COPD. Effective with or without a chronic bronchitis phenotype. Must be reconstituted and given by a healthcare professional.

Smoking-cessation pharmacotherapy

Offer alongside behavioural counselling at every quit attempt — pharmacotherapy roughly doubles quit success compared with counselling alone.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Varenicline	Days 1-3: 0.5 mg PO once daily Days 4-7: 0.5 mg PO BID Day 8 onward: 1 mg PO BID for a total 12-week course; a second 12-week course may be considered after successful cessation	Nausea, abnormal/vivid dreams, headache, neuropsychiatric symptoms (monitor for mood change)	None significant	One of the most effective single smoking-cessation agents. Start 1-2 weeks before the planned quit date; a gradual quit approach is also supported.
Nicotine Replacement Therapy	Patch: 21 mg/24h tapering to 14 then 7 mg/24h over approximately 6-10 weeks (lower starting strength if smoking fewer than 10 cigarettes/day) Gum: 2 mg or 4 mg by baseline cigarette use, up to 24 pieces/day, tapered over approximately 8-12 weeks Lozenge: 2 mg or 4 mg by time-to-first-cigarette, up to 20 lozenges/day, tapered over approximately 8-12 weeks	Patch: local skin irritation, vivid dreams. Gum/lozenge: mouth/throat irritation, hiccups, dyspepsia	Stopping smoking itself (not the NRT) can raise levels of drugs cleared via CYP1A2 (e.g., theophylline)	Combining a patch with an as-needed gum or lozenge for breakthrough cravings is more effective than either form alone. Bupropion is a further alternative smoking-cessation agent for patients who prefer a non-nicotine, non-varenicline option.

Systemic corticosteroid (acute exacerbation only)

No role for chronic maintenance oral corticosteroid therapy in COPD. Tapering is unnecessary for courses under 2 weeks.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Prednisone	Adults: 30-40 mg PO once daily for 5 days	GI upset, fluid/electrolyte imbalance, hyperglycemia, hypertension, insomnia, mood change, dermal thinning, cataracts, decreased bone mineral density	Increased GI ulceration with NSAIDs; levels increased by CYP3A4 inhibitors (clarithromycin, erythromycin, ketoconazole); efficacy decreased by barbiturates, phenytoin, rifampin; hypokalemia with thiazides; decreases vaccine response	Give within 30 days of exacerbation onset — administration beyond 30 days after the exacerbation is not recommended. No advantage to IV over oral administration.

Long-term oxygen therapy (intervention, not a drug)

Drug	Dosage	Adverse effects	Drug interactions	Comments
Long-term oxygen therapy (LTOT)	Criteria: PaO2 ≤55 mmHg (or under 60 mmHg with cor pulmonale, peripheral edema, or hematocrit >56%) on room air, at rest, when clinically stable Titration: flow via nasal prongs or Venturi mask, titrated to a resting PaO2 of 65-80 mmHg; increase by 1-2 L/min during exercise and sleep Duration: at least 15 hours/day; continuous use gives the greatest survival benefit	Nasal/facial dryness, epistaxis; fire risk if the patient smokes near the oxygen source	None significant	Continuous use provides the greatest survival benefit; monitor for worsening hypercapnia when titrating in a patient with hypoventilation.

Pulmonary rehabilitation (intervention, not a drug)

Drug	Dosage	Adverse effects	Drug interactions	Comments
Pulmonary rehabilitation	Program: structured, typically 6-12 weeks, 2-3 supervised sessions/week combining exercise training with education	Transient exercise-related fatigue or muscle soreness	None significant	Refer early — benefit occurs at every COPD severity stage, not only advanced disease. Initiate or resume within 4 weeks after an exacerbation.

Oral antibiotics for acute exacerbations

Reserve antibiotics for exacerbations meeting at least 2 of the 3 cardinal symptoms (increased dyspnea, increased sputum volume, increased sputum purulence), or for any exacerbation severe enough to require invasive mechanical ventilation. Choose empirically using the patient's exacerbation frequency and recent antibiotic exposure, and switch to a different antibiotic class if the same class was used within the past 3 months or if the patient has not responded within 24-36 hours.

Risk category	Typical pathogens	Preferred antibiotics	Alternative antibiotics
Fewer than 4 exacerbations in the past year, no antibiotics in the past 3 months	Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae	Amoxicillin, doxycycline, or sulfamethoxazole/trimethoprim, each x 5-7 days	—
4 or more exacerbations in the past year, OR failure of a first-choice agent, OR antibiotics within the past 3 months	Organisms above, plus Enterobacteriaceae and Pseudomonas species — higher probability of resistance in this group	Amoxicillin/clavulanate x 5-10 days, cefuroxime axetil x 5-10 days, or levofloxacin x 5 days	Azithromycin x 3 days or clarithromycin x 5-10 days

Penicillins

Drug	Dosage	Adverse effects	Drug interactions	Comments
Amoxicillin	Adults: 1000 mg PO TID x 5-7 days	Rash, anaphylaxis (rare)	May increase methotrexate levels; may enhance warfarin's anticoagulant effect	First-choice agent for a lower-risk exacerbation.
Amoxicillin/Clavulanate	Standard: 875 mg PO BID x 5-10 days Alternative: 500 mg PO TID x 5-10 days	Anaphylaxis, GI upset, diarrhea	May increase methotrexate levels; may enhance warfarin's anticoagulant effect	Preferred agent for a higher-risk exacerbation.

Sulfonamide combination

Drug	Dosage	Adverse effects	Drug interactions	Comments
Sulfamethoxazole/Trimethoprim	Adults: 800/160 mg (2 regular-strength or 1 double-strength tablet) PO BID x 5-7 days	Nausea, skin rash, Stevens-Johnson syndrome (rare)	May increase warfarin effect; may increase phenytoin levels; may increase methotrexate toxicity

Tetracycline

Drug	Dosage	Adverse effects	Drug interactions	Comments
Doxycycline	Loading dose: 200 mg PO x 1 dose Maintenance: 100 mg PO BID, 5-7 days total	GI upset, photosensitivity	Iron or antacids decrease absorption; carbamazepine, phenytoin, rifampin decrease doxycycline levels

Cephalosporin

Drug	Dosage	Adverse effects	Drug interactions	Comments
Cefuroxime	Adults: 500 mg PO BID x 5-10 days	GI intolerance, rash, anaphylaxis (rare)	May enhance warfarin's anticoagulant effect

Fluoroquinolones

Reserve for higher-risk exacerbations; avoid in myasthenia gravis and with other QTc-prolonging drugs.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Ciprofloxacin	Adults: 500-750 mg PO BID x 7-21 days	Headache, dizziness, peripheral neuropathy, tendon rupture (rare), QTc prolongation	Antacids/sucralfate/metal cations decrease absorption; may increase theophylline and warfarin levels; avoid with Class IA/III antiarrhythmics	Reserve for patients at specific risk of Pseudomonas aeruginosa.
Levofloxacin	Standard: 750 mg PO once daily x 5 days Alternative: 500 mg PO once daily x 7 days	Headache, dizziness, peripheral neuropathy, tendon rupture (rare), QTc prolongation, rare severe liver injury	Antacids/sucralfate/metal cations decrease absorption; may increase theophylline and warfarin levels; avoid with Class IA/III antiarrhythmics
Moxifloxacin	Adults: 400 mg PO once daily x 5 days	Headache, dizziness, peripheral neuropathy, tendon rupture (rare), QTc prolongation	Antacids/sucralfate/metal cations decrease absorption; avoid with Class IA/III antiarrhythmics

Macrolides

Drug	Dosage	Adverse effects	Drug interactions	Comments
Azithromycin (exacerbation treatment)	Standard: 500 mg PO once daily x 3 days Alternative: 500 mg PO x 1 dose, then 250 mg PO once daily x 4 days	GI intolerance, QTc prolongation	Contraindicated with pimozide; caution with other QTc-prolonging drugs; may increase digoxin and warfarin effect	Distinct from the lower, prophylactic dosing regimen listed above.
Clarithromycin	Standard: 500 mg PO BID x 5-10 days Extended-release: 1000 mg PO once daily x 5-10 days	Bitter taste, GI intolerance, QTc prolongation	Strong CYP3A4 inhibitor — interacts with atorvastatin, some benzodiazepines, carbamazepine, colchicine, cyclosporine, ergots, lovastatin/simvastatin, theophylline, and more; contraindicated with pimozide

Vaccines

See Non-Pharmacologic Treatment for the full recommendation set and Canadian eligibility criteria.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Influenza vaccine (inactivated)	Adults: 1 dose annually	Local injection reaction, mild transient systemic symptoms	None significant	Annual, given early in the fall. Avoid the live-attenuated vaccine in chronic lung disease.
Pneumococcal 20-valent conjugate vaccine	Adults: 1 dose	Local injection reaction, mild fever	None significant	1 dose for adults with COPD aged 50 and older, regardless of prior pneumococcal vaccination.
Pneumococcal 21-valent conjugate vaccine	Adults: 1 dose	Local injection reaction, mild fever	None significant	Alternative conjugate vaccine option; covers additional serotypes not in the 20-valent product.
RSV vaccine (bivalent prefusion F)	Adults: 1 dose	Local injection reaction, fatigue, myalgia	None significant	Strongly recommended at 75+, at 65-74 with increased risk (includes COPD), and at any age 18+ if on home/chronic oxygen therapy.
Tdap vaccine	Adults: 1 dose	Local injection reaction	None significant	For patients with COPD not vaccinated against pertussis in adolescence.
Recombinant zoster vaccine	Adults: 2-dose series per product schedule	Local injection reaction, myalgia, fatigue	None significant	Routine adult immunization per standard age-based schedule.

References

Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease: 2026 Report — Global Initiative for Chronic Obstructive Lung Disease (GOLD). GOLD 2026 Report
2023 Canadian Thoracic Society Guideline on Pharmacotherapy in Patients with Stable COPD — Canadian Thoracic Society (Bourbeau J, Bhutani M, Hernandez P, et al.). Can J Respir Crit Care Sleep Med 2023;7(4):159-201
Standardized questionnaire on respiratory symptoms: a statement prepared and approved by the MRC Committee on the Aetiology of Chronic Bronchitis (MRC breathlessness score) — British Medical Journal (Fletcher CM). BMJ 1960;2(5213):1665
Development and first validation of the COPD Assessment Test — European Respiratory Journal (Jones PW, Harding G, Berry P, et al.). Eur Respir J 2009;34(3):648-654
Alpha-1 antitrypsin deficiency targeted testing and augmentation therapy: a Canadian Thoracic Society clinical practice guideline — Canadian Respiratory Journal (Marciniuk DD, Hernandez P, Balter M, et al.). Can Respir J 2012;19(2):109-116
Indacaterol-glycopyrronium versus salmeterol-fluticasone for COPD — New England Journal of Medicine (Wedzicha JA, Banerji D, Chapman KR, et al.). N Engl J Med 2016;374(23):2222-2234
Immunization of persons with chronic diseases: Canadian Immunization Guide — Public Health Agency of Canada / National Advisory Committee on Immunization (NACI). Canadian Immunization Guide, Part 3
Summary of the NACI statement of April 10, 2026: Updated guidance on respiratory syncytial virus (RSV) vaccines for older adults and for adults at high risk of severe RSV disease — National Advisory Committee on Immunization (NACI), Public Health Agency of Canada. NACI statement, April 10, 2026
An Updated Definition and Severity Classification of Chronic Obstructive Pulmonary Disease Exacerbations: The Rome Proposal — American Journal of Respiratory and Critical Care Medicine (Celli BR, Fabbri LM, Aaron SD, et al.). Am J Respir Crit Care Med 2021;204(11):1251-1258

Professional reference only. Apply clinical judgment and verify patient-specific decisions against current authoritative guidance and product information.