HIV Infection: Treatment

Clinical Snapshot

HIV is a chronic retroviral infection that, left untreated, progressively damages the immune system and eventually causes death from opportunistic infections or AIDS-defining cancers. Since the mid-1990s, combination antiretroviral therapy (ART) has transformed that trajectory: sustained viral suppression on ART allows near-normal immune function and life expectancy.^[1] The standard of care today is "test and treat" — offering ART to every person with a confirmed HIV diagnosis as soon as possible, ideally the same day the diagnosis is confirmed, regardless of CD4 count or symptoms — because earlier initiation improves survival and because a person with a durably suppressed viral load essentially cannot transmit HIV sexually.^[2]^[3] This chapter covers treatment of adults with an already-confirmed HIV-1 diagnosis; screening and pre-/post-exposure prophylaxis for HIV-negative individuals are covered in the separate HIV Infection: Prevention chapter.

Recognize the Condition

The clinical spectrum of established HIV infection

Many people are asymptomatic at diagnosis and for years afterward; others present with constitutional symptoms (fatigue, weight loss, lymphadenopathy) or an overt opportunistic infection or AIDS-defining illness. CD4 count is the key marker of where a patient sits on this spectrum and which complications become relevant.

CD4 count	Clinically relevant risk that becomes active
Any count	HIV itself confers an increased risk of non-AIDS cancers, cardiovascular disease, and hepatic/renal disease even before immunosuppression becomes severe — this is why ART is started regardless of CD4 count, not only once a threshold is crossed.
Under 200 cells/mcL	Risk of Pneumocystis jirovecii pneumonia (PCP) — evaluate for primary prophylaxis (see Drug Tables).
Under 100 cells/mcL, Toxoplasma IgG-positive	Risk of toxoplasmic encephalitis — evaluate for primary prophylaxis.
Under 50 cells/mcL	Risk of disseminated Mycobacterium avium complex (MAC) and CMV retinitis rises; monitoring intensifies. Current guidance reserves routine MAC prophylaxis for patients who are not on ART, remain viremic despite ART, or have no fully suppressive regimen option (see Drug Tables) — it is not routinely needed when ART is started promptly.^[4]

Recognizing immune reconstitution inflammatory syndrome (IRIS)

As the immune system recovers after starting ART, it can mount an exaggerated inflammatory response to a pre-existing infection — either "unmasking" a previously subclinical opportunistic infection or causing a "paradoxical" worsening of one already being treated. IRIS typically appears within days to a few weeks of starting or restarting ART, and is most common in patients who start with a very low CD4 count (roughly under 50-100 cells/mcL) and a rapid subsequent CD4 rise or viral load drop. It presents as new or worsening fever, lymphadenopathy, or localizing symptoms referable to the specific unmasked or paradoxically-worsening infection (for example, worsening respiratory symptoms and new lymphadenopathy in tuberculosis-associated IRIS, or new visual symptoms in cytomegalovirus-associated IRIS) — it is easy to mistake for treatment failure or a new infection if this pattern is not specifically considered.^[5]

Recognizing virologic failure

Unlike an acute opportunistic infection, virologic failure is usually silent — it is detected through routine viral load monitoring rather than through symptoms, which is why the monitoring schedule in this chapter matters as much as the initial regimen choice.

Risk Factors

Low baseline CD4 count or high baseline viral load at the time ART is started.
Delayed ART initiation after diagnosis.
Nonadherence — the single most important modifiable driver of virologic failure and drug resistance.
Active substance use, untreated mental illness, or unstable housing, food, or financial insecurity — all strongly affect adherence and retention in care.
Hepatitis B or C coinfection.
Active, untreated tuberculosis or latent tuberculosis infection.
Transmitted (pretreatment) drug-resistant virus.
Pregnancy — ART selection and urgency both change (see Special Populations).
Adolescents and young adults transitioning between pediatric and adult care, who are at particular risk of gaps in follow-up.
Significant drug-drug interactions with a patient's other medications that reduce antiretroviral levels below the threshold needed for suppression.

Red Flags & Refer

Escalate or refer urgently for any of the following:

Signs of an abacavir hypersensitivity reaction — fever, rash, gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal pain), and constitutional symptoms (malaise, fatigue, achiness), typically within the first 6 weeks of starting abacavir and worsening with each subsequent dose. Stop abacavir immediately and never rechallenge — even in a patient who tested HLA-B*5701-negative, a genuine clinical hypersensitivity reaction is a lifelong contraindication, since rechallenge after a true reaction can cause severe or fatal hypotension and anaphylaxis.
Signs of immune reconstitution inflammatory syndrome (IRIS) — new or significantly worsening symptoms of an infection appearing days to weeks after starting or restarting ART, especially in a patient who started with a CD4 count under 50-100 cells/mcL. Do not assume treatment failure or a new, unrelated infection without considering this specifically.^[5]
Signs of a significant opportunistic infection requiring urgent specialist care — severe headache with altered mental status or focal neurologic findings (suggesting a CNS process such as toxoplasmic encephalitis, cryptococcal meningitis, or PML), new visual changes (suggesting CMV retinitis), severe respiratory distress, or high fever with hemodynamic instability.
Confirmed virologic failure — an inability to maintain a viral load under 200 copies/mL despite ART, confirmed on repeat testing.
A severe cutaneous reaction — blistering, mucosal involvement, or skin sloughing (suggesting Stevens-Johnson syndrome or toxic epidermal necrolysis), most associated with NNRTIs, particularly nevirapine.
Signs of lactic acidosis or severe hepatic steatosis — nausea, vomiting, abdominal pain, and unexplained dyspnea, a rare but serious toxicity of older NRTIs (particularly zidovudine).
New or worsening severe depression, suicidal ideation, or other significant neuropsychiatric symptoms after starting an integrase inhibitor or efavirenz.
A newly diagnosed or late-presenting pregnant patient — needs urgent specialist involvement to select an appropriate regimen and minimize the window without treatment.

Assessment & Diagnosis

History

At-risk behaviours and estimated duration of infection where it can be established; general indicators (anorexia, weight loss, fatigue, lymphadenopathy) and symptoms suggesting an opportunistic infection (fever, night sweats, cough, dyspnea, diarrhea, headache, skin rashes); sexual history and the HIV status of regular partners; mental health, substance use, and social history (housing stability, drug coverage, social support, disclosure concerns); past medical history including other sexually transmitted infections, prior opportunistic infections or AIDS-defining conditions, tuberculosis exposure/testing history, hepatitis A/B/C, varicella, comorbidities that affect regimen choice (renal, hepatic, cardiovascular disease, diabetes, osteoporosis, peripheral neuropathy, mental health disorders, substance use), allergies, immunization history, complete medication history (prescription, nonprescription, complementary/alternative, and any prior antiretroviral exposure including PrEP), and reproductive history/pregnancy plans.

Physical examination

Height, weight, BMI, blood pressure, waist circumference; focused assessment of mental health and cognitive status; skin, oral cavity, lymph nodes, abdomen, and genital/rectal examination (including cervical cytology where applicable).

Baseline investigations

Confirm HIV status with an antibody/antigen test if a prior positive result is not already documented.
Plasma HIV RNA (viral load) and CD4 count/percentage — the key prognostic markers and the baseline against which treatment response is measured.
Genotypic resistance testing at baseline, as soon as possible after diagnosis — do not wait to start ART for this result to return; start a regimen expected to remain active against most resistance patterns and adjust once results are available. Repeat resistance testing with any confirmed virologic failure (viral load rebound above 200 copies/mL on therapy).^[2]
Screen every patient for the HLA-B*5701 allele before starting abacavir. A positive result is recorded in the chart as a lifelong abacavir allergy/contraindication — do not use abacavir in a patient who tests positive, even though most HLA-B*5701-positive patients would never actually develop a reaction; the test is used because a true reaction can be severe or fatal.^[6]
A tropism assay (to determine CCR5, CXCR4, or dual/mixed tropism) is needed only if maraviroc is being considered — this is not a routine baseline test.
CBC with differential and platelets; liver panel (ALT, AST, bilirubin, albumin, INR) and renal panel (creatinine, eGFR, phosphorus, urinalysis, urine albumin- or protein-to-creatinine ratio); fasting glucose and/or HbA1c and a lipid panel; pregnancy test where relevant.
Hepatitis A, B, C, syphilis, and Toxoplasma serologies (abdominal ultrasound if hepatitis B or C is positive); gonorrhea/chlamydia testing by site of exposure; tuberculosis screening (TST and/or IGRA), with a chest x-ray and sputum studies if indicated; a serum cryptococcal antigen if the CD4 count is under 100 cells/mcL.

Treatment Targets

Achieve and maintain viral suppression below the detection limit of the assay used (commonly under 20-40 copies/mL) — virologic failure is defined as an inability to sustain a viral load under 200 copies/mL.
Restore and preserve CD4 count and overall immune function.
Prevent opportunistic infections and AIDS-defining illness.
Prevent onward sexual transmission of HIV — a durably suppressed viral load (confirmed for at least 6 months, with good adherence) reduces sexual transmission risk to a negligible level.
Delay or prevent the emergence of drug-resistant HIV.
Slow disease progression, prolong survival, and improve quality of life.

Choose Initial Treatment

Direct treatment rule

Start ART in every person with confirmed HIV infection as soon as possible after diagnosis, regardless of CD4 count, viral load, or symptoms — offer same-day or as-soon-as-possible initiation once the patient is ready, rather than deferring to a later visit.^[2]^[3]

Do not delay ART start to await most baseline results — the exception is HLA-B*5701 testing when abacavir is the specific agent being considered; start a regimen not built around abacavir if that result is still pending.^[6]

Preferred initial regimen 2 nucleos(t)ide reverse transcriptase inhibitors (N[t]RTIs) plus a second-generation integrase inhibitor — either the single-tablet combination bictegravir/emtricitabine/tenofovir alafenamide, or dolutegravir plus an emtricitabine/tenofovir (disoproxil fumarate or alafenamide) backbone — for most people starting therapy, consistent with the European AIDS Clinical Society guideline as well.^[2]^[7]^[8]

Also preferred the single-tablet combination dolutegravir/abacavir/lamivudine, only if the patient has tested HLA-B*5701-negative.

2-drug regimen option dolutegravir/lamivudine is a reasonable alternative in selected patients — specifically those with a baseline viral load under 500,000 copies/mL, no hepatitis B coinfection, and started only once those 2 results are back (unlike the integrase-inhibitor triple regimens above, do not start this 2-drug option before confirming both).^[2]^[7]

When an integrase-inhibitor-based regimen is not an option (intolerance, interaction, resistance, or unavailability) — use a ritonavir- or cobicistat-boosted protease inhibitor (e.g. darunavir-based) or an NNRTI-based regimen (doravirine is generally better tolerated than efavirenz or nevirapine) plus a 2-N[t]RTI backbone instead.

Rilpivirine-containing regimens — use only when the baseline viral load is 100,000 copies/mL or under and the CD4 count is over 200 cells/mcL; rilpivirine is not recommended to start outside these limits. Dolutegravir/rilpivirine is a 2-drug option specifically for virologically suppressed patients switching therapy, not for initial treatment.

Never rechallenge with abacavir after any hypersensitivity reaction, regardless of HLA-B*5701 status.

Non-Pharmacologic Treatment

Adherence counselling and support at every visit — pillboxes, reminder apps, pharmacist-led follow-up, and addressing drug coverage or access barriers — since adherence is the single most important determinant of durable viral suppression.^[7]
General counselling at every visit, regardless of CD4 count: risk of onward transmission and how to reduce it, the legal implications of not disclosing HIV status to sexual partners (which vary by jurisdiction — direct patients to local legal resources when this is a concern), proper nutrition, physical activity, and the importance of ongoing follow-up.
Tuberculosis screening (TST and/or IGRA) with treatment of latent tuberculosis infection when indicated.
Vaccination: pneumococcal vaccine; hepatitis A and B vaccines if nonimmune on serology; updated diphtheria/tetanus/pertussis; annual influenza; MMR and varicella if the CD4 count is over 200 cells/mcL and the patient is not pregnant; meningococcal vaccine periodically; HPV, herpes zoster, and COVID-19 vaccines per current local guidelines; mpox vaccine where available and appropriate.
Cervical cytology (Pap testing) and anal cytology screening where indicated, per local screening guidance.
Screen for and address comorbid mental health and substance use concerns, and unstable housing, food, or financial insecurity — these strongly affect both adherence and retention in care.
Harm-reduction services (sterile injection equipment, opioid agonist therapy) for people who inject drugs.
Contraception and pregnancy-planning counselling, since ART regimen choice differs meaningfully around a planned or confirmed pregnancy (see Special Populations).
Antiretroviral drug-interaction counselling — this is one of the highest-yield things a pharmacist does for a person on ART. Integrase inhibitors that are not boosted (dolutegravir, bictegravir, raltegravir) have GI absorption impaired by polyvalent cations — separate dolutegravir- or bictegravir-containing regimens from calcium, iron, magnesium, or aluminum-containing antacids, laxatives, sucralfate, or mineral supplements by roughly 2 hours before or 6 hours after (raltegravir has its own specific spacing requirements — check the product monograph, since the high-dose once-daily tablet and the standard twice-daily tablet differ). A cobicistat- or ritonavir-boosted regimen (darunavir/cobicistat, darunavir/ritonavir, atazanavir/ritonavir, elvitegravir/cobicistat combinations) is a potent CYP3A inhibitor with a broad interaction footprint — review every new prescription and over-the-counter/natural health product against a validated, currently maintained HIV drug-interaction resource (for example, the University of Liverpool HIV Drug Interactions checker) before dispensing, since boosted regimens can substantially raise levels of statins (avoid simvastatin and lovastatin outright; reduce the dose of others), hormonal contraceptives (efficacy can be reduced — recommend a backup method), inhaled or intranasal corticosteroids (risk of Cushing syndrome and adrenal suppression, most documented with fluticasone), and PDE5 inhibitors (reduce the dose).

Pharmacologic Treatment Options

Initial ART regimen tracks

Preferred: integrase-inhibitor-based triple therapy

2 N[t]RTIs plus a second-generation integrase inhibitor (bictegravir, or dolutegravir) -- the recommended starting point for most people with HIV.

Alternative: 2-drug integrase-inhibitor regimen

Dolutegravir/lamivudine, for selected patients with a baseline viral load under 500,000 copies/mL and no hepatitis B coinfection.

Alternative: boosted-PI-based or NNRTI-based regimen

Used when an integrase-inhibitor-based regimen is not an option because of intolerance, interaction, resistance, or unavailability.

Special situation: treatment-experienced, multidrug-resistant HIV

Maraviroc (CCR5-tropic virus only, tropism-tested), fostemsavir, and lenacapavir are reserved for heavily treatment-experienced patients with limited options because of resistance, contraindication, or intolerance to other classes.

Drug / intervention	Role	Dose / use	Important adverse effects	Teaching points
Bictegravir / emtricitabine / tenofovir alafenamide Preferred	Preferred single-tablet initial regimen for most people	1 tablet (50 mg/200 mg/25 mg) PO once daily, with or without food	GI upset, insomnia, headache, weight gain; monitor renal function	Lowest pill burden of the preferred integrase-inhibitor options. Not recommended if creatinine clearance is under 30 mL/min.
Dolutegravir + emtricitabine/tenofovir (DF or AF) Preferred	Preferred initial regimen, separate-agent option	Combo: dolutegravir 50 mg PO once daily + emtricitabine/tenofovir (DF or AF) PO once daily	Insomnia and other CNS effects, weight gain; early benign creatinine rise	Separate from polyvalent-cation products by about 2 h before or 6 h after. Significantly raises metformin levels.
Dolutegravir / abacavir / lamivudine Preferred	Preferred single-tablet regimen, HLA-B*5701-negative only	1 tablet (50 mg/600 mg/300 mg) PO once daily, with or without food	Abacavir hypersensitivity (screen first); insomnia, weight gain	Never use, and never rechallenge, in a patient who is HLA-B*5701-positive or has had a hypersensitivity reaction.
Dolutegravir / lamivudine Alternative	2-drug initial regimen, selected patients	1 tablet (50 mg/300 mg) PO once daily, with or without food	Insomnia, weight gain	Only if baseline viral load is under 500,000 copies/mL and hepatitis B has been excluded -- confirm both before starting.
Darunavir/cobicistat/emtricitabine/tenofovir alafenamide Alternative	Boosted-PI single-tablet regimen when an integrase inhibitor is not an option	1 tablet (800 mg/150 mg/200 mg/10 mg) PO once daily with food	Diarrhea, nausea, headache, rash; rare hepatotoxicity	Cobicistat has extensive CYP3A interactions -- review the full medication list. Not recommended if creatinine clearance is under 30 mL/min.
Doravirine / lamivudine / tenofovir disoproxil fumarate Alternative	NNRTI-based single-tablet regimen, better tolerated than older NNRTIs	1 tablet (100 mg/300 mg/300 mg) PO once daily, with or without food	GI effects, headache, dizziness, sleep disturbance	Preferred NNRTI-based option over efavirenz/nevirapine given fewer CNS/hepatic effects and fewer interactions.
Emtricitabine / rilpivirine / tenofovir alafenamide Special situation	Rilpivirine-based single-tablet regimen, restricted eligibility	1 tablet (200 mg/25 mg/25 mg) PO once daily with food	Depression, insomnia, rash, headache; QTc prolongation	Only start if baseline viral load is 100,000 copies/mL or under and CD4 is over 200. Rilpivirine absorption is acid-dependent -- PPIs are contraindicated.
Rilpivirine / cabotegravir (long-acting injectable) Special situation	Injectable switch regimen for virologically suppressed patients	Optional 28-day oral lead-in, then 2 injections (cabotegravir 600 mg + rilpivirine 900 mg IM) one month apart, then both IM monthly or every 2 months thereafter	Injection-site reactions, insomnia, headache, depression	Only for patients already virologically suppressed (under 50 copies/mL) -- not for initial ART. Avoid in pregnancy.
Lenacapavir (treatment-experienced) Special situation	Capsid inhibitor, heavily treatment-experienced multidrug-resistant HIV	Oral 600 mg Day 1 and Day 2, then 300 mg Day 8; subcutaneous 927 mg (2 injections) Day 15, then 927 mg SC every 26 weeks	Injection-site reactions (can persist weeks), nausea, headache	Always combined with an optimized background regimen chosen with resistance testing. Drug levels persist over a year after stopping.
Maraviroc Special situation	CCR5 antagonist, CCR5-tropic virus only	300 mg PO BID (adjusted for interacting drugs -- see Drug Tables)	Generally well tolerated; rare hepatotoxicity	Requires a tropism assay before use -- effective only against CCR5-tropic virus. Not for initial therapy.
Fostemsavir Special situation	Attachment inhibitor, heavily treatment-experienced multidrug-resistant HIV	600 mg PO BID, with or without food	Diarrhea, nausea, headache, fatigue; QTc prolongation	Reserved for patients with multidrug resistance and limited remaining options.

Special Populations

Pregnancy: offer ART to every pregnant patient with HIV, with a discussion of risks and benefits; base the specific regimen on resistance testing results where available. Preferred N[t]RTI backbones are emtricitabine/tenofovir disoproxil fumarate or emtricitabine/tenofovir alafenamide (both coformulated). The preferred integrase inhibitors in pregnancy are bictegravir and dolutegravir — bictegravir/emtricitabine/tenofovir alafenamide is now a preferred single-tablet regimen in pregnancy per the current DHHS Perinatal HIV Guideline update, alongside dolutegravir-based triple therapy.^[9] When dolutegravir is used before or during pregnancy, ensure adequate folic acid supplementation — an early Botswana cohort signal of a small increase in neural tube defects with dolutegravir around conception has not persisted in updated analyses from the same cohort, but folic acid supplementation is still recommended.^[9] 2-drug regimens are not routinely preferred in pregnancy — dolutegravir/lamivudine is classified only as an alternative, and specifically only in a patient without prior long-acting cabotegravir PrEP exposure.^[9] The preferred boosted protease inhibitor in pregnancy, when a PI-based regimen is needed, is twice-daily darunavir/ritonavir; cobicistat should not be used as a pharmacokinetic booster in pregnancy, since it produces insufficient drug levels in the second and third trimesters. Raltegravir (twice daily) is an alternative integrase inhibitor in pregnancy. Long-acting injectable cabotegravir is not recommended in pregnancy given its long half-life and a lack of pregnancy safety data.

Breastfeeding

A person on ART with a sustained, suppressed viral load has a low, but not zero, risk of transmitting HIV to an infant through breastfeeding; replacement feeding with infant formula eliminates that risk. Provide evidence-based, non-judgmental counselling on infant feeding options to support shared decision-making, rather than defaulting to a single recommendation for every patient.

Renal impairment

Tenofovir disoproxil fumarate requires dose-interval adjustment as creatinine clearance falls, and caution is warranted with pre-existing or high risk of osteoporosis given its bone mineral density effect; tenofovir alafenamide has a smaller effect on renal function and bone density and is often preferred at lower creatinine clearance, though most tenofovir alafenamide combination products are also not recommended below a specific creatinine clearance threshold (commonly 30 mL/min) — check the specific product. Elvitegravir/cobicistat combinations have their own, higher renal cutoffs. Darunavir, dolutegravir, bictegravir (as part of its combination product, subject to the same renal floor as its backbone), raltegravir, and lenacapavir do not require dose adjustment for renal impairment.

Hepatic impairment

Most antiretrovirals require no adjustment in mild-to-moderate hepatic impairment; boosted protease inhibitors carry the most hepatotoxicity risk and need closer monitoring. Consult product-specific guidance for severe (Child-Pugh C) impairment.

Hepatitis B coinfection

Use a backbone with 2 agents active against both HIV and hepatitis B — emtricitabine or lamivudine plus tenofovir (disoproxil fumarate or alafenamide). Never discontinue or switch off these agents without ensuring continued hepatitis B coverage — stopping them abruptly can precipitate a severe hepatitis B flare.

Hepatitis C coinfection

Screen for significant interactions between the antiretroviral regimen and direct-acting antiviral hepatitis C therapy before starting either — several antiretrovirals and DAAs share metabolic pathways.

Older adults

No specific dose adjustment is generally required based on age alone, but screen more closely for polypharmacy-related interactions, renal function decline, and cardiovascular/bone comorbidities that affect regimen choice.

Pediatrics and adolescents

This chapter's dosing is for adults. Pediatric and adolescent antiretroviral dosing is weight- and age-based, differs substantially from adult dosing, and must be directed by a pediatrician or pediatric HIV specialist using pediatric-specific guidance — do not extrapolate adult doses downward.

Mental health and substance use comorbidity

Avoid efavirenz in patients with a history of anxiety, depression, or psychosis given its CNS toxicity profile. Integrase inhibitors, particularly dolutegravir, have also been associated with insomnia and other neuropsychiatric effects in some patients — monitor for this after starting or switching to any integrase-inhibitor-based regimen.

Monitoring & Follow-Up

Routine monitoring, once on ART

Plasma viral load every 3-4 months; this can be extended to every 6 months once the patient has an undetectable viral load and good adherence on a stable regimen for over 1 year, and should be increased again if the patient becomes symptomatic or is diagnosed with an AIDS-defining illness. CD4 count every 3-4 months; CD4 monitoring becomes optional once the viral load is undetectable and the CD4 count has been 300 cells/mcL or higher for 1-2 years, and should resume if the patient becomes symptomatic or is diagnosed with AIDS. Genotypic resistance testing at baseline and again with any confirmed viral load rebound above 200 copies/mL.^[2]

Renal function (creatinine/eGFR, urinalysis) and hepatic function at baseline and periodically thereafter — more frequently with a tenofovir- or boosted-PI-containing regimen. Fasting lipids and glucose/HbA1c periodically, since several antiretroviral classes affect metabolic risk. Consider bone density assessment in patients with additional osteoporosis risk factors on a tenofovir disoproxil fumarate-containing regimen. History and physical examination at least annually, including reinforcement of adherence, vaccination status, and cancer screening appropriate to age and risk (including cervical and anal cytology where indicated).

After starting or changing ART

Watch specifically for signs of immune reconstitution inflammatory syndrome in the weeks after starting or restarting ART, particularly in a patient who started with a very low CD4 count.^[5] Reassess tolerability within the first weeks, since most antiretroviral adverse effects that prompt a regimen change occur early.

Update the complete medication history — prescription, nonprescription, and complementary/alternative products, including short-term and non-oral medications such as seasonal allergy treatments and inhalers — at every visit, and screen for interactions whenever anything changes.

Treatment Failure / Next Step

Confirm virologic failure — an inability to maintain a viral load under 200 copies/mL, confirmed on repeat testing rather than acted on from a single result.
Assess adherence first, along with drug-drug and drug-food interactions and any absorption issue (for example, a missed spacing interval between an integrase inhibitor and a polyvalent-cation product) — these are more common causes of an isolated rebound than true resistance.
If confirmed rebound persists, obtain genotypic resistance testing while the patient remains on the current (failing) regimen, or within about 4 weeks of stopping it — resistant mutations can become undetectable once drug pressure is removed, so testing off therapy for longer than this risks a falsely reassuring result.^[2]
Select a new regimen with at least 2, and preferably 3, fully active agents based on the resistance results and the patient's complete antiretroviral history — involve an HIV specialist for anything beyond a straightforward first failure.
Never reduce to, or continue on, only 1 or 2 drugs of a failing regimen while deciding on a new one — if a regimen must be stopped for toxicity, stop all agents simultaneously and start the replacement regimen together, since partial continuation promotes further resistance.
Before concluding a patient has failed treatment, rule out immune reconstitution inflammatory syndrome as an alternative explanation for new or worsening symptoms, particularly soon after starting or changing therapy.
Once resuppressed, address any modifiable barrier that was identified (psychosocial support, cost/coverage, pill burden) — switching to a lower-burden single-tablet or long-acting option is often appropriate once the patient is stable and virologically suppressed.

Common Errors to Avoid

Starting abacavir without a documented negative HLA-B*5701 result.
Rechallenging with abacavir after any hypersensitivity reaction, even in a patient who previously tested HLA-B*5701-negative.
Stopping only 1 or 2 drugs of a multidrug regimen instead of the entire regimen simultaneously when a change is needed — this promotes resistance.
Planned treatment interruptions ("drug holidays") — shown to increase the risk of opportunistic infection and death compared with continuous ART; treatment interruptions are not recommended.^[10]
Taking an unboosted integrase inhibitor (dolutegravir, bictegravir, raltegravir) at the same time as a calcium, iron, magnesium, or aluminum-containing product without the required spacing interval.
Missing hepatitis B coinfection before stopping or switching a patient off tenofovir- or emtricitabine/lamivudine-containing therapy — this can precipitate a hepatitis B flare.
Starting a rilpivirine-containing regimen at a viral load above 100,000 copies/mL or a CD4 count of 200 cells/mcL or under.
Using cobicistat as a pharmacokinetic booster in the second or third trimester of pregnancy.
Assuming new or worsening symptoms shortly after starting ART automatically mean treatment failure, without considering immune reconstitution inflammatory syndrome.
Missing a clinically significant interaction — rifampin with most integrase inhibitors, NNRTIs, and boosted protease inhibitors; dolutegravir/bictegravir significantly raising metformin levels; proton pump inhibitors, which are contraindicated with rilpivirine and with atazanavir.
Delaying ART initiation while waiting on baseline results that are not actually needed before starting (the only true exception is HLA-B*5701 when abacavir specifically is planned).
Forgetting to repeat genotypic resistance testing with a confirmed virologic rebound, or waiting too long after stopping a failing regimen to send it.

Clinical Decision Algorithm

Confirmed HIV diagnosis: starting antiretroviral therapy

New or confirmed HIV-1 diagnosis

Send baseline labs: genotypic resistance test, CD4, viral load, HLA-B*5701 if abacavir is being considered, coinfection screen, pregnancy test

No urgent competing issue

Start ART as soon as possible, ideally the same day -- do not wait for results, except HLA-B*5701 if abacavir is the specific agent planned

Active severe opportunistic infection needing urgent treatment first (e.g. cryptococcal meningitis, active TB with CNS involvement)

Treat or stabilize the acute opportunistic infection first, then start ART -- generally within about 2 weeks, per the specific infection's own guidance

Selecting the initial regimen

ART-naive adult, no unusual baseline resistance concern identified

No specific constraint identified

Bictegravir/emtricitabine/tenofovir alafenamide single tablet, or dolutegravir + emtricitabine(or lamivudine)/tenofovir backbone

HLA-B*5701-negative, abacavir-based option preferred

Dolutegravir/abacavir/lamivudine single tablet

Baseline viral load under 500,000 copies/mL and hepatitis B excluded

Dolutegravir/lamivudine 2-drug regimen is a reasonable alternative

Integrase-inhibitor-based regimen not an option (intolerance, interaction, resistance, unavailability)

Boosted darunavir-based regimen, or an NNRTI-based regimen (doravirine preferred over efavirenz/nevirapine) plus a 2-N[t]RTI backbone

Baseline viral load 100,000 copies/mL or under and CD4 over 200

A rilpivirine-containing single-tablet regimen is an additional option within these limits

Suspected virologic failure

Confirmed viral load rebound above 200 copies/mL on ART

Assess and address adherence, drug-drug/drug-food interactions, and absorption/spacing issues

Nonadherence or an interaction fully explains the rebound

Address the specific barrier identified (simplify regimen, resolve interaction, add adherence support) and continue routine monitoring -- resistance testing not yet required

Adherence confirmed and interactions excluded, or rebound persists

Obtain genotypic resistance testing while remaining on the current regimen, or within about 4 weeks of stopping it

Select a new regimen with at least 2, preferably 3, fully active agents based on resistance results and full ART history -- involve an HIV specialist

Opportunistic infection prophylaxis by CD4 count

ART started or offered to every patient, regardless of CD4 count

CD4 under 200 cells/mcL

Start PCP prophylaxis (trimethoprim-sulfamethoxazole preferred) -- can generally stop once CD4 is over 200 for at least 3 months on ART

CD4 under 100 cells/mcL and Toxoplasma IgG-positive

Add/continue toxoplasmosis prophylaxis (trimethoprim-sulfamethoxazole covers both PCP and toxoplasmosis) -- can generally stop once CD4 is over 200 for at least 3 months on ART

CD4 under 50 cells/mcL, and not on ART, remains viremic on ART, or has no fully suppressive regimen option

Consider MAC prophylaxis (azithromycin weekly) -- not routinely needed when ART is started promptly and expected to suppress the viral load

Drug Tables

How to use this table: Doses shown are adult doses and require patient-specific confirmation, including renal/hepatic adjustment. Pediatric and adolescent antiretroviral dosing is weight-based and differs substantially from adult dosing -- it is not included here; see Special Populations. Select any drug name to open its complete Pharmasist Drug Database page.

Integrase strand transfer inhibitors (INSTIs)

Fewer drug interactions than boosted regimens, but GI absorption is reduced by polyvalent cations.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Dolutegravir	Standard dosing: 50 mg PO once daily With integrase-resistant virus: 50 mg PO BID	Insomnia and other CNS effects, weight gain; early benign creatinine rise (first 2-4 weeks, then stable)	Separate from polyvalent-cation products by about 2 h before or 6 h after. Significantly raises metformin levels.	May remain active against raltegravir- and elvitegravir-resistant virus. Available as dispersible tablets.
Bictegravir	Combination product only: See emtricitabine/tenofovir alafenamide combination row	Similar to dolutegravir: GI upset, insomnia, weight gain	Same polyvalent-cation spacing as dolutegravir; raises metformin levels	Not available as a single-entity product in Canada -- only as the emtricitabine/tenofovir AF combination.
Raltegravir	Standard tablet: 400 mg PO BID High-dose tablet: 1200 mg PO once daily	Weight gain; rare severe skin/hypersensitivity reactions; infrequent neuropsychiatric effects (insomnia, depression); myopathy/rhabdomyolysis (rare)	Not a CYP inhibitor/inducer. Rifampin decreases levels -- increase dose if coadministered. Do not combine any strength with aluminum/magnesium antacids; avoid calcium-containing antacids with the high-dose tablet.	Available as chewable tablets. The standard and high-dose tablets are not interchangeable.
Cabotegravir (oral)	Oral lead-in: 30 mg PO once daily with food, taken together with rilpivirine 25 mg PO once daily	Insomnia, headache	Should be taken 2 h before or 4 h after polyvalent-cation products. Strong UGT1A1/1A9 inducers (e.g. rifampin, carbamazepine, phenytoin) may cause virologic failure.	Used only as a short-term oral lead-in before, or as bridging for, injectable cabotegravir/rilpivirine -- not for initial antiviral therapy on its own.

Non-nucleoside reverse transcriptase inhibitors (NNRTIs)

All carry numerous potential drug interactions -- consult a validated interaction resource before adding or removing any medication.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Doravirine	Standard dosing: 100 mg PO once daily, with or without food	GI effects, headache, dizziness, sleep disturbance, rash; rare severe hypersensitivity or IRIS	Numerous potential interactions -- consult a reputable interaction checker.	Generally better tolerated than efavirenz or nevirapine; preferred NNRTI when this class is used.
Efavirenz	Standard dosing: 600 mg PO once daily on an empty stomach	CNS toxicity (sleep disturbance, abnormal dreams, depressed mood), rash, transaminase elevation, QTc prolongation	Numerous potential interactions -- consult a reputable interaction checker.	Avoid in patients with a history of anxiety, depression, or psychosis. Take on an empty stomach.
Etravirine	Standard dosing: 200 mg PO BID with food	Rash, nausea; rare severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme)	Numerous potential interactions -- consult a reputable interaction checker.	May remain active against some NNRTI-resistant virus; specialist-directed use.
Nevirapine	Lead-in: 200 mg PO once daily for 2 weeks Maintenance: 200 mg PO BID (immediate-release), or 400 mg PO once daily (extended-release)	Rash, rare severe skin reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis); rare fatal hepatitis	Numerous potential interactions -- consult a reputable interaction checker.	Do not start if CD4 is above the sex-specific threshold associated with higher hepatotoxicity risk -- confirm current product-specific guidance before initiating.
Rilpivirine	Standard dosing: 25 mg PO once daily with food	Depression, insomnia, rash, headache; early benign creatinine rise; QTc prolongation	Absorption is acid-dependent -- proton pump inhibitors are contraindicated; separate from antacids and H2-receptor antagonists per product-specific timing.	Only start if baseline viral load is 100,000 copies/mL or under and CD4 is over 200. Take with a substantial meal.

Nucleoside/nucleotide reverse transcriptase inhibitors (N[t]RTIs)

The antiretroviral backbone of most regimens; generally fewer CYP-mediated interactions than boosted or NNRTI regimens.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Abacavir	Standard dosing: 600 mg PO once daily, or 300 mg PO BID	Hypersensitivity reaction in HLA-B*5701-positive patients (can be severe or fatal); some observational data link recent use to increased myocardial infarction risk	Low interaction potential.	Screen for HLA-B*5701 before starting; a positive result is a lifelong contraindication. Never rechallenge after any hypersensitivity reaction.
Lamivudine	Standard dosing: 300 mg PO once daily, or 150 mg PO BID	Generally well tolerated; minimal toxicity	Low interaction potential.	Avoid combining with emtricitabine -- both select for the same resistance mutation.
Zidovudine	Standard dosing: 300 mg PO BID, or 200 mg PO TID	Nausea, headache, malaise, fatigue, anemia, leukopenia, myopathy, hepatic steatosis; long-term lipoatrophy	Additive hematologic toxicity with other marrow-suppressive drugs (e.g. dapsone, ganciclovir, ribavirin).	Largely superseded by better-tolerated N[t]RTIs; retained mainly for specific combination products or specialist situations.
Tenofovir disoproxil fumarate	Standard dosing: 300 mg PO once daily	Renal toxicity; decreased bone mineral density and increased fracture risk; rare lactic acidosis/hepatic steatosis	Avoid combining with other nephrotoxic drugs.	Dose-interval adjustment needed if creatinine clearance is under 50 mL/min. Ensure adequate calcium/vitamin D intake, especially with osteoporosis risk factors.
Tenofovir alafenamide	Standard dosing: 25 mg PO once daily (as part of a combination product)	Smaller renal and bone density effect than tenofovir DF; still requires renal monitoring	Should not be combined with rifamycins.	Preferred over tenofovir DF when renal or bone concerns are prominent; most combination products are not recommended below a creatinine clearance of about 30 mL/min.

Protease inhibitors (boosted)

Extensive CYP3A-mediated interaction potential -- review the complete medication list before starting any of these.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Atazanavir	Unboosted, treatment-naive: 400 mg PO once daily with food Boosted: 300 mg + ritonavir 100 mg PO once daily with food	Benign hyperbilirubinemia; less commonly kidney stones, gallstones, rash; PR/QTc prolongation, dyslipidemia, insulin resistance	Absorption is acid-dependent -- PPIs are contraindicated; stagger antacids/H2-blockers.	Boost with low-dose ritonavir except in select treatment-naive patients using the unboosted dose.
Darunavir	Treatment-naive: 800 mg + ritonavir 100 mg PO once daily with food Treatment-experienced with PI resistance, or pregnant: 600 mg + ritonavir 100 mg PO BID with food	Diarrhea, nausea, headache, rash (possible cross-sensitivity with sulfonamides); rare hepatotoxicity; PR/QTc prolongation, dyslipidemia, insulin resistance	Extensive CYP3A interactions -- consult a reputable interaction checker.	Always given with ritonavir or cobicistat as a booster -- never as a sole protease inhibitor.
Darunavir/cobicistat	Standard dosing: 800 mg/150 mg PO once daily with food	Same as darunavir above, plus early benign creatinine rise from cobicistat	Extensive CYP3A interactions via cobicistat -- consult a reputable interaction checker.	Cobicistat has no antiviral activity of its own -- it is a pharmacokinetic booster only. Avoid as the booster in the second/third trimester of pregnancy.
Lopinavir/ritonavir	Treatment-naive: 400 mg/100 mg PO BID, or 800 mg/200 mg PO once daily, with food With efavirenz or nevirapine: 400/100, 500/125, or 600/150 mg PO BID with food -- confirm product-specific dose	GI upset, transaminase elevation; PR/QTc prolongation, dyslipidemia, insulin resistance	Extensive CYP3A interactions -- consult a reputable interaction checker.	Largely superseded by darunavir-based regimens given a heavier pill burden and GI tolerability profile.
Ritonavir (as a booster)	Booster dose: See the specific boosted protease inhibitor for the paired ritonavir dose	GI upset, diarrhea, circumoral paresthesia, transaminase elevation	Potent CYP3A inhibitor -- extensive interactions; avoid as a sole protease inhibitor.	Used at low dose purely as a pharmacokinetic booster for atazanavir, darunavir, or lopinavir -- not used as a standalone antiretroviral.

CCR5 antagonist, attachment inhibitor, and capsid inhibitor (treatment-experienced, multidrug-resistant HIV)

Reserved for patients with limited remaining options because of resistance, contraindication, or intolerance to first-line classes.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Maraviroc	Standard dosing (no strong CYP3A4 interactors): 300 mg PO BID With strong CYP3A4 inhibitors: 150 mg PO BID With strong CYP3A4 inducers: 600 mg PO BID	Generally well tolerated; rare hepatotoxicity	Levels reduced by CYP3A4 inducers (efavirenz, etravirine, rifampin); raised by CYP3A4 inhibitors (protease inhibitors, azole antifungals, clarithromycin) -- dose must be adjusted accordingly.	A tropism assay is required before use -- effective only against CCR5-tropic virus, not CXCR4 or dual/mixed-tropic virus.
Fostemsavir	Standard dosing: 600 mg PO BID, with or without food	Diarrhea, nausea, headache, fatigue; QTc prolongation	Numerous potential interactions -- consult a reputable interaction checker or resource.	For heavily treatment-experienced patients with multidrug-resistant HIV-1 failing their current regimen.
Lenacapavir	Oral lead-in: 600 mg PO Day 1, 600 mg PO Day 2, 300 mg PO Day 8 Initiation injection: 927 mg (2 subcutaneous injections) on Day 15 Maintenance: 927 mg (2 subcutaneous injections) every 26 weeks	Injection-site reactions (pain, swelling, nodule -- can persist weeks), nausea, headache, fatigue	Metabolized via CYP3A, UGT1A1, and P-glycoprotein -- avoid strong inducers of these pathways (rifampin, carbamazepine, phenytoin, St. John's wort), which cause loss of efficacy.	First-in-class capsid inhibitor for heavily treatment-experienced adults with multidrug-resistant HIV-1, always combined with an optimized background regimen. Drug levels persist over a year after the last dose.

Evidence note: Lenacapavir efficacy and safety data in heavily treatment-experienced patients with multidrug-resistant HIV-1 are from the CAPELLA trial.^[11]

Complete single-tablet and combination regimens

Combining agents into 1 tablet improves adherence; interaction and adverse-effect profiles follow each component drug above.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Bictegravir/emtricitabine/tenofovir alafenamide	Standard dosing: 1 tablet (50 mg/200 mg/25 mg) PO once daily	See bictegravir and tenofovir alafenamide above	See dolutegravir-class INSTI spacing note above; metformin levels may rise	Preferred initial single-tablet regimen for most people.
Dolutegravir/abacavir/lamivudine	Standard dosing: 1 tablet (50 mg/600 mg/300 mg) PO once daily	See abacavir and dolutegravir above	Same polyvalent-cation spacing as dolutegravir	Requires a negative HLA-B*5701 result before starting.
Dolutegravir/lamivudine	Standard dosing: 1 tablet (50 mg/300 mg) PO once daily	See dolutegravir above	Same polyvalent-cation spacing as dolutegravir	Only start with baseline viral load under 500,000 copies/mL and hepatitis B excluded.
Dolutegravir/rilpivirine	Standard dosing: 1 tablet (50 mg/25 mg) PO once daily with food	See dolutegravir and rilpivirine above	Rilpivirine's acid-dependent absorption and PPI contraindication apply	Switch-only 2-drug regimen for patients already virologically suppressed -- not for initial therapy.
Doravirine/lamivudine/tenofovir disoproxil fumarate	Standard dosing: 1 tablet (100 mg/300 mg/300 mg) PO once daily	See doravirine and tenofovir DF above	See doravirine above	Not recommended if creatinine clearance is under 50 mL/min.
Efavirenz/emtricitabine/tenofovir disoproxil fumarate	Standard dosing: 1 tablet (600 mg/200 mg/300 mg) PO once daily on an empty stomach	See efavirenz and tenofovir DF above	See efavirenz above	Take on an empty stomach. Largely superseded by better-tolerated regimens for initial therapy.
Elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide	Standard dosing: 1 tablet (150 mg/150 mg/200 mg/10 mg) PO once daily with food	See darunavir/cobicistat interaction note pattern above (cobicistat-boosted); diarrhea, headache	Cobicistat is a potent CYP3A inhibitor -- extensive interactions; separate from polyvalent-cation antacids by at least 2 h.	Not recommended if creatinine clearance is under 30 mL/min. Not preferred for initial therapy given the older booster-based interaction burden compared with unboosted integrase-inhibitor regimens.
Elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate	Standard dosing: 1 tablet (150 mg/150 mg/200 mg/300 mg) PO once daily with food	See above, plus tenofovir DF's renal/bone effects	Same cobicistat interaction burden as above	Not recommended if creatinine clearance is under 70 mL/min. Not preferred for initial therapy.
Emtricitabine/tenofovir alafenamide	Standard dosing: 1 tablet (200 mg/25 mg) PO once daily	See tenofovir alafenamide above	Should not be combined with rifamycins	N[t]RTI backbone, paired with a separate 3rd agent.
Emtricitabine/tenofovir disoproxil fumarate	Standard dosing: 1 tablet (200 mg/300 mg) PO once daily	See tenofovir DF above	Avoid other nephrotoxic drugs	N[t]RTI backbone, paired with a separate 3rd agent. Not recommended if creatinine clearance is under 30 mL/min.
Emtricitabine/rilpivirine/tenofovir alafenamide	Standard dosing: 1 tablet (200 mg/25 mg/25 mg) PO once daily with food	See rilpivirine above	Rilpivirine's acid-dependent absorption and PPI contraindication apply	Only start with baseline viral load 100,000 copies/mL or under and CD4 over 200.
Emtricitabine/rilpivirine/tenofovir disoproxil fumarate	Standard dosing: 1 tablet (200 mg/25 mg/300 mg) PO once daily with a substantial meal	See rilpivirine and tenofovir DF above	Rilpivirine's acid-dependent absorption and PPI contraindication apply	Only start with baseline viral load 100,000 copies/mL or under and CD4 over 200. Take with a substantial-calorie meal.
Lamivudine/zidovudine	Standard dosing: 1 tablet (150 mg/300 mg) PO BID	See lamivudine and zidovudine above	Additive hematologic toxicity with other marrow-suppressive drugs	Largely superseded by better-tolerated N[t]RTI backbones.
Darunavir/cobicistat/emtricitabine/tenofovir alafenamide	Standard dosing: 1 tablet (800 mg/150 mg/200 mg/10 mg) PO once daily with food	See darunavir/cobicistat above	Extensive CYP3A interactions via cobicistat	Not recommended if pretreatment creatinine clearance is under 30 mL/min.
Rilpivirine/cabotegravir (long-acting injectable)	Initiation: Cabotegravir 600 mg + rilpivirine 900 mg IM, then again 1 month later Maintenance: Cabotegravir 400-600 mg + rilpivirine 600-900 mg IM monthly or every 2 months, per the chosen schedule	Injection-site reactions, insomnia, headache, depression; early benign creatinine rise; QTc prolongation	No formal interaction studies with other drugs; theoretical loss of efficacy with strong UGT1A1/1A9 inducers.	Optional 28-day oral lead-in with cabotegravir 30 mg + rilpivirine 25 mg once daily; only for patients already virologically suppressed. Avoid in pregnancy.

Opportunistic infection prophylaxis

Thresholds and regimens for the 2 CD4-driven prophylaxis decisions most relevant to community and specialist pharmacists -- see the algorithm above for the decision structure.

Drug	Dosage	Adverse effects	Drug interactions	Comments
Trimethoprim-sulfamethoxazole	PCP/toxoplasmosis prophylaxis: 1 double-strength (160 mg/800 mg) tablet PO once daily; 1 single-strength tablet daily or 1 double-strength tablet 3 times weekly are accepted alternative schedules	GI upset, rash, myelosuppression, hyperkalemia	Additive myelosuppression with other antifolate/marrow-suppressive drugs; potentiates warfarin.	Preferred agent for both PCP prophylaxis (CD4 under 200) and toxoplasmosis prophylaxis (CD4 under 100 and Toxoplasma IgG-positive) -- 1 regimen covers both indications.
Dapsone	PCP prophylaxis alone: 100 mg PO once daily Toxoplasmosis prophylaxis (with pyrimethamine + leucovorin): 50 mg PO once daily	Hemolysis (check G6PD status first), methemoglobinemia, rash, GI upset	Additive myelosuppression with other marrow-suppressive drugs (e.g. zidovudine, ganciclovir).	Alternative PCP prophylaxis when trimethoprim-sulfamethoxazole is not tolerated; combined with pyrimethamine and leucovorin for toxoplasmosis prophylaxis specifically.
Atovaquone	PCP or toxoplasmosis prophylaxis: 1500 mg PO once daily with food	GI upset, rash, headache	Rifamycins substantially reduce levels.	Alternative PCP and toxoplasmosis prophylaxis when trimethoprim-sulfamethoxazole and dapsone are both not tolerated. Absorption is improved by taking with a fatty meal.
Pyrimethamine	Toxoplasmosis prophylaxis (with dapsone + leucovorin): 50 mg PO once weekly	Bone marrow suppression (leukopenia, thrombocytopenia, megaloblastic anemia) -- dose-limiting	Additive myelosuppression with other antifolate drugs; always given with leucovorin.	Used with dapsone (or atovaquone) and leucovorin as an alternative toxoplasmosis prophylaxis regimen. Not commercially marketed in Canada -- obtained via Health Canada's Special Access Programme or compounding.
Leucovorin (folinic acid)	With pyrimethamine, toxoplasmosis prophylaxis: 25 mg PO once weekly	Generally well tolerated	None significant.	Always co-administered with pyrimethamine to protect bone marrow -- do not substitute plain folic acid, which does not provide the same protection and can reduce pyrimethamine's efficacy.
Azithromycin	MAC prophylaxis: 1200 mg PO once weekly	GI upset, QTc prolongation	Fewer interactions than clarithromycin.	Preferred agent for MAC prophylaxis in the specific patients for whom it is still indicated (see algorithm above) -- routine primary MAC prophylaxis is no longer recommended for most patients starting ART promptly.
Clarithromycin	MAC prophylaxis: 500 mg PO BID	GI upset, metallic taste, QTc prolongation	Significant CYP3A interactions -- review the full antiretroviral regimen.	Alternative to azithromycin for MAC prophylaxis when indicated.

References

Initiation of antiretroviral therapy in early asymptomatic HIV infection — New England Journal of Medicine (Lundgren JD, Babiker AG, Gordin F, et al.; INSIGHT START Study Group). N Engl J Med 2015;373(9):795-807
Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents With HIV — Panel on Antiretroviral Guidelines for Adults and Adolescents, US Department of Health and Human Services. Updated May 27, 2026
RAPID antiretroviral therapy: high virologic suppression rates with immediate antiretroviral therapy initiation in a vulnerable urban clinic population — AIDS (Coffey S, Bacchetti P, Sachdev D, et al.). AIDS 2019;33(5):825-832
Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV — NIH/CDC/HIVMA/IDSA, US Department of Health and Human Services. Updated May 27, 2026
Immune reconstitution inflammatory syndrome in patients starting antiretroviral therapy for HIV infection: a systematic review and meta-analysis — The Lancet Infectious Diseases (Müller M, Wandel S, Colebunders R, et al.). Lancet Infect Dis 2010;10(4):251-261
HLA-B*5701 screening for hypersensitivity to abacavir — New England Journal of Medicine (Mallal S, Phillips E, Carosi G, et al.). N Engl J Med 2008;358(6):568-579
Antiretroviral Drugs for Treatment and Prevention of HIV Infection in Adults: 2024 Recommendations of the International Antiviral Society-USA Panel — JAMA (Gandhi RT, Landovitz RJ, Sax PE, et al.). JAMA 2025;333(7):609-628
Major revision version 13.0 of the European AIDS Clinical Society guidelines 2025 — HIV Medicine (Ambrosioni J, et al.). HIV Med 2026
Recommendations for the Use of Antiretroviral Drugs During Pregnancy and Interventions to Reduce Perinatal HIV Transmission in the United States — Panel on Treatment of HIV During Pregnancy and Prevention of Perinatal Transmission, US Department of Health and Human Services. 2026 update
CD4+ count-guided interruption of antiretroviral treatment — New England Journal of Medicine (Strategies for Management of Antiretroviral Therapy (SMART) Study Group; El-Sadr WM, Lundgren J, et al.). N Engl J Med 2006;355(22):2283-2296
Capsid inhibition with lenacapavir in multidrug-resistant HIV-1 infection — New England Journal of Medicine (Segal-Maurer S, DeJesus E, Stellbrink HJ, et al.). N Engl J Med 2022;386(19):1793-1803

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