Narcolepsy

Narcolepsy is a chronic disorder characterized by excessive daytime sleepiness (EDS), caused by a deficiency of the orexin (hypocretin) neuropeptide that regulates wakefulness.^[1] It affects roughly 1 in 2,000 people in Canada; global prevalence is estimated at 25-50 per 100,000, with typical onset during adolescence and a second, smaller peak at ages 30-39.^[1]

Narcolepsy is classified into two types by the presence or absence of cataplexy. Type 1 narcolepsy (narcolepsy with cataplexy) often includes a pentad of excessive daytime sleepiness, cataplexy, sleep paralysis, hallucinations while falling asleep, and fragmented sleep — though not all five features need be present.^[1] Type 2 narcolepsy lacks cataplexy entirely.^[1] Of Canadians with narcolepsy, approximately 60-70% experience cataplexy on top of excessive daytime sleepiness.^[1]

Type 1 narcolepsy is now understood mechanistically as an immune-mediated process: T-cell-driven destruction of the small population of hypocretin (orexin)-producing neurons in the lateral hypothalamus, strongly associated with the HLA subtype HLA-DQB1*06:02, which is present in over 90% of Type 1 cases.^[2] This allele is also carried by a meaningful share of the general population, however, making it a necessary but not a sufficient cause on its own; infections are thought to contribute as a possible environmental trigger for the autoimmune process in genetically susceptible individuals.^[2] Type 2 narcolepsy, by contrast, is not consistently associated with measurable hypocretin deficiency, and its underlying mechanism is less well defined.

The pentad, and why most patients do not have all five features

Type 1 narcolepsy is classically taught as a pentad: excessive daytime sleepiness, cataplexy, sleep paralysis, hallucinations while falling asleep (hypnagogic) or waking (hypnopompic), and fragmented nocturnal sleep.^[1] In practice, most patients present with excessive daytime sleepiness plus only some of the remaining features — waiting for a "complete" pentad before considering the diagnosis is a genuine source of missed or delayed recognition. Excessive daytime sleepiness is the one feature present in essentially all patients, in both types, and is usually the presenting complaint that first brings a patient to a pharmacy or primary care visit.

Type 1 versus Type 2 — the key distinguishing feature

^[1][2]

Functional impact is real and often underappreciated: school and work performance decline, and relationship difficulties are common as the condition disrupts a patient's ability to stay engaged and alert through ordinary daily activities.^[1]

• HLA-DQB1*06:02 — present in over 90% of Type 1 narcolepsy cases, reflecting the disorder's autoimmune, T-cell-mediated basis, though this allele is also carried by a meaningful share of the general population and is therefore necessary but not sufficient on its own to cause disease.^[2]
• An autoimmune process targeting hypocretin (orexin)-producing neurons in the lateral hypothalamus, with infection proposed as a possible environmental trigger in genetically susceptible individuals.^[2]
• Adolescent onset is the typical pattern, with a second, smaller onset peak at ages 30-39 — a bimodal age distribution worth keeping in mind when a "first" presentation occurs later in adulthood.^[1]
• A family history of narcolepsy modestly raises risk relative to the general population, though most cases are sporadic.
• Secondary (symptomatic) narcolepsy from a structural hypothalamic lesion, tumour, traumatic brain injury, or a paraneoplastic process is uncommon but real, and should be considered specifically when onset is abrupt, occurs outside the typical adolescent/young-adult age range, or is accompanied by other neurological findings.
• Rare genetic and metabolic disorders (for example, Niemann-Pick disease type C) can produce a cataplexy-like phenotype in children and should be kept in the differential for atypical paediatric presentations.

Narcolepsy requires objective sleep testing

Unlike several other conditions in this guideline library, narcolepsy is not diagnosed on history and examination alone. Multiple Sleep Latency Testing (MSLT) is the first-line diagnostic test, conducted the day after an overnight polysomnography (PSG).^[1] The overnight PSG first excludes another primary sleep disorder (particularly obstructive sleep apnea) and confirms adequate total sleep time, so that a short MSLT sleep latency the next day genuinely reflects narcolepsy rather than untreated sleep-disordered breathing or sleep deprivation.

The MSLT protocol

The MSLT includes 5 monitored daytime nap opportunities, scheduled 2 hours apart, assessing the patient's propensity to fall asleep and to enter REM sleep abnormally quickly during a nap.^[1] A short mean sleep latency across the naps, together with 2 or more sleep-onset REM periods (a REM period beginning within about 15 minutes of falling asleep, well before REM would normally occur), supports the diagnosis; one of the required sleep-onset REM periods may be substituted by a sleep-onset REM period observed on the preceding overnight PSG.

Cerebrospinal fluid hypocretin-1

Where lumbar puncture is performed (typically at a dedicated sleep or neurology centre rather than as a routine primary-care test), a CSF hypocretin-1 concentration of 110 pg/mL or lower is diagnostic for Type 1 narcolepsy and can be particularly useful when MSLT results are equivocal or when a patient cannot safely discontinue an interfering medication before testing.^[2]

Before testing: exclude the mimics

A 1-2 week period of actigraphy or a sleep diary before PSG/MSLT helps exclude chronic insufficient sleep, which can itself produce a short MSLT latency and false-positive-appearing results. Directly relevant differential diagnoses to screen for and exclude before attributing excessive daytime sleepiness to narcolepsy include: insufficient sleep syndrome, obstructive sleep apnea, a circadian rhythm disorder (including shift work disorder), medication- or substance-induced hypersomnolence (sedating drugs, alcohol, cannabis), a mood disorder, and idiopathic hypersomnia (typically longer, less refreshing naps, without cataplexy and with fewer or no sleep-onset REM periods on MSLT).^[1]

Confirming the type

Once the diagnosis of narcolepsy is confirmed, Type 1 versus Type 2 is distinguished by the presence or absence of cataplexy and, where measured, by CSF hypocretin-1.^[2] This distinction matters directly for treatment selection, since the only Health Canada-approved cataplexy-specific therapies (sodium oxybate and the lower-sodium oxybate salts) are indicated for cataplexy, which by definition only Type 1 patients have.

• Reduce excessive daytime sleepiness enough to allow safe, functional daily activity at school, at work, and — once sustained control is demonstrated — behind the wheel.
• Control cataplexy to prevent physical injury from sudden falls and to reduce the real psychosocial burden of unpredictable, emotion-triggered episodes.
• Consolidate fragmented nocturnal sleep, since poor-quality nighttime sleep both worsens daytime symptoms and is itself a distinct, treatable target for some agents (notably the oxybates).
• Address sleep paralysis and hypnagogic/hypnopompic hallucinations when they are frequent or distressing enough to warrant treatment in their own right.
• Treat narcolepsy as the lifelong condition it is — with treatment, many patients regain near-normal function, but ongoing therapy and periodic reassessment, not a fixed one-time regimen, is the expectation.{C(cmaj)}
• Enable safe return to driving once genuinely sustained symptom control is demonstrated, and counsel proactively before that point (see Special Populations).
• Recognize and manage psychiatric and mood comorbidity, both as part of the condition itself and as a genuine adverse effect of some therapies.
• Minimize medication-related harms specific to this drug class: cardiovascular risk from stimulants and wake-promoting agents, abuse/diversion potential and restricted-distribution requirements for the oxybates, and unplanned pregnancy risk from the contraceptive-efficacy interaction shared by several agents in this chapter.

Excessive daytime sleepiness

First-line modafinil 200 mg/day, divided into a morning and a noon dose, titrated by 100 mg increments to a usual maximum of 400 mg/day; the second dose should generally be taken no later than early afternoon to minimize insomnia risk.^[5] Modafinil has no significant effect on cataplexy — do not select it expecting cataplexy benefit.^[5] First-line alternative solriamfetol 75 mg once daily on awakening, doubled after at least 3 days to a maximum of 150 mg/day if needed and tolerated; avoid dosing within 9 hours of planned bedtime.^[6] Not marketed in Canada armodafinil, the R-enantiomer of modafinil, carries a conditional AASM recommendation and may appear on a cross-border or transferred prescription, but is not available through a Canadian pharmacy and is contraindicated as a hypersensitivity risk in patients who cannot tolerate modafinil.^[8][5] Conditional recommendation, older stimulant class methylphenidate or dextroamphetamine, both genuinely indicated for narcolepsy on their current Canadian product monographs (not merely for ADHD), individualized from a low starting dose and titrated to effect, with meaningfully greater cardiovascular and abuse-potential burden than modafinil or solriamfetol.^[7][10][8]

Cataplexy

First-line, Health Canada-approved specifically for cataplexy sodium oxybate, starting at 4.5 g/night divided into two equal doses of 2.25 g (the first at bedtime, the second 2.5-4 hours later), titrated in 1.5 g/night increments to a maximum of 9 g/night, with 2-week intervals recommended between dose changes; up to 8-10 weeks of therapy may be needed before a maximal cataplexy response is seen, so avoid judging this drug too early.^[4] Preferred where sodium intake is a concern the lower-sodium oxybate salts (calcium, magnesium, potassium, and sodium oxybates), containing the same active moiety (oxybate/GHB) but with approximately 92% less sodium than sodium oxybate at an equivalent dose — the same twice-nightly dosing scheme applies, starting at 4.5 g/night and titrated to a maximum of 9 g/night, with 1-week (rather than 2-week) intervals generally recommended between titrations.^[9] Patients transitioning from sodium oxybate to the lower-sodium salts are initiated at the same gram-for-gram dose and adjusted from there based on response and tolerability.^[9] Required before starting either oxybate enrollment of the prescriber, the pharmacy, and the patient in the manufacturer's Controlled Distribution Program (the same program covers both products, administered through Innomar Strategies) — see Special Populations and Monitoring & Follow-up for what this involves in practice.^[4][9] Off-label alternative, particularly where rapid onset or lower regulatory burden is a priority venlafaxine or clomipramine are widely used in practice for cataplexy given their much faster onset than sodium oxybate, though the AASM guideline made no formal recommendation for the SSRI/SNRI class specifically, citing insufficient/inconclusive trial-level evidence — individualize and set expectations accordingly rather than presenting these as equivalent, evidence-graded alternatives to the oxybates.^[8]

Pitolisant — a genuine option with a real Canadian access barrier

Pitolisant is an oral histamine H3-receptor antagonist/inverse agonist that increases histaminergic neurotransmission to promote wakefulness, and is the only agent in this chapter with a formal Health Canada indication for both excessive daytime sleepiness and cataplexy.^[11] It carries a strong AASM recommendation.^[8] However, the CDA-AMC (CADTH) Canadian Drug Expert Committee reviewed pitolisant in December 2022 and recommended it not be reimbursed by Canadian public drug plans: two double-blind, randomized, controlled comparative trials (HARMONY I and HARMONY Ibis) failed to demonstrate that pitolisant was at least as good as modafinil for excessive daytime sleepiness, and while pitolisant did reduce weekly cataplexy episodes versus placebo in the HARMONY CTP trial (2.27 versus 4.51 episodes/week), results were inconsistent across trials and the committee could not conclude the drug met identified patient priorities given these limitations.^[11] At an estimated annual cost of roughly $6,074 to $12,147 per patient, discuss this real access and cost barrier with patients directly before recommending pitolisant as a first choice in Canada.^[11]

• Scheduled naps — brief, strategically timed naps (for example, two to three 15-20 minute naps at predictable points in the day) are widely used in practice as an adjunct to pharmacotherapy, though the AASM guideline made no formal recommendation on scheduled naps specifically, citing insufficient evidence to grade the practice — present this as a reasonable, low-risk adjunct rather than an evidence-graded standalone therapy.^[8]
• Sleep hygiene and a consistent sleep-wake schedule — adequate, regular nocturnal sleep duration reduces the severity of daytime symptoms; sleep deprivation from any cause tends to worsen both excessive daytime sleepiness and cataplexy frequency.
• Patient and family/school/employer education is itself part of treatment — helping the people around a patient understand that cataplexy is involuntary and that sleep attacks are not a matter of willpower reduces stigma and improves safety planning.^[1]
• Avoid alcohol and other sedating substances, which worsen excessive daytime sleepiness and are also specifically contraindicated in combination with sodium oxybate/the lower-sodium oxybate salts (see Pharmacologic Treatment Options and Special Populations).
• Regular exercise and weight management support overall alertness and cardiovascular health, which is particularly relevant given the cardiovascular considerations of several narcolepsy drug classes.
• Proactive safety planning around cataplexy triggers — avoiding known high-risk activities (for example, driving, swimming alone, or operating machinery) during a period of poor cataplexy control, and counseling on how to respond safely if an episode occurs.
• Psychological support or counselling for the genuine psychosocial impact of narcolepsy — school/work performance decline and relationship strain are recognized consequences, not incidental complaints.^[1]

Pregnancy and reproductive potential

Modafinil is contraindicated in pregnancy based on post-marketing reports, modafinil may cause fetal harm; pregnancy registry data documented major congenital anomalies (including cardiac anomalies) at a higher prevalence than background rates among infants exposed in utero.^[5] A negative pregnancy test is required before starting modafinil in a patient of reproductive potential.^[5] A genuinely important, easily missed interaction modafinil, armodafinil, and pitolisant may each reduce the effectiveness of steroidal (hormonal) contraceptives via CYP3A4/5 induction — advise effective non-hormonal or alternative contraception during treatment and for 2 months after stopping modafinil specifically.^[5][8] Sodium oxybate and the lower-sodium oxybate salts have limited human pregnancy data; weigh benefit against risk with the prescriber and avoid use where feasible. Stimulants (methylphenidate, dextroamphetamine) should be used at the lowest effective dose in pregnancy, in direct consultation with the prescriber, given limited dedicated safety data for this specific indication.

Children and adolescents

Onset commonly occurs during adolescence, so paediatric presentations are genuinely expected, not rare.^[1] In Canada, neither sodium oxybate nor the lower-sodium oxybate salts is authorized for pediatric use — no data are available to Health Canada for patients under 18, in contrast to their approved pediatric use in some other jurisdictions.^[4][9] Modafinil is likewise not authorized for pediatric use in Canada.^[5] Methylphenidate and dextroamphetamine both carry a genuine, current Canadian narcolepsy indication and are used under specialist care in children old enough for the specific product's approved age range, individualized and titrated cautiously given the class's cardiovascular and psychiatric monitoring requirements.^[7][10]

Older adults

There is very limited experience with sodium oxybate and the lower-sodium oxybate salts in patients 65 years and older; start at the low end of the dosing range and monitor closely for impaired motor and cognitive function.^[4][9] Modafinil elimination is reduced with aging — use lower doses.^[5] Stimulant cardiovascular risk (hypertension, arrhythmia) becomes more consequential as baseline cardiovascular disease prevalence rises with age.

Hepatic impairment

Sodium oxybate and the lower-sodium oxybate salts: start at one-half the usual dose, divided into two doses, in patients with hepatic impairment.^[4][9] Modafinil: reduce the dose by one-half in severe hepatic impairment.^[5]

Renal impairment

Sodium oxybate and the lower-sodium oxybate salts require no dose adjustment for renal impairment (less than 5% of sodium oxybate is renally excreted), though no studies have been conducted in renal failure and the sodium load of standard sodium oxybate is a separate, real consideration in significant renal impairment.^[4][9] Solriamfetol requires meaningful renal dose adjustment: mild impairment (creatinine clearance 60-89 mL/min) needs no adjustment; moderate impairment (30-59 mL/min) starts at 37.5 mg/day, increasing to a 75 mg/day maximum after 7 days if tolerated; severe impairment (15-29 mL/min) is limited to a 37.5 mg/day maximum, used only if benefit is judged to outweigh risk; end-stage renal disease (below 15 mL/min) is a contraindication.^[6]

Cardiovascular disease

Modafinil requires a baseline cardiac evaluation, including an ECG, before starting, particularly with coronary artery disease, a recent MI, or unstable angina; monitor blood pressure and heart rate through treatment and discontinue if arrhythmia or moderate-to-severe hypertension develops.^[5] Solriamfetol is contraindicated with an MI within the past year, unstable angina, uncontrolled hypertension, or serious cardiac arrhythmias; blood pressure and heart rate should be controlled and monitored before and during treatment.^[6] Methylphenidate is contraindicated in moderate-to-severe hypertension and significant structural cardiac disease.^[7] Standard sodium oxybate's real sodium load (up to roughly 1,638 mg of sodium at the 9 g/night maximum dose) is a specific reason to prefer the lower-sodium oxybate salts in patients with hypertension, heart failure, or salt-restricted diets.^[4][9]

MAOI use

Solriamfetol, methylphenidate, and dextroamphetamine are each contraindicated with concurrent MAOI use or within 14 days of stopping an MAOI, given the risk of a hypertensive crisis.^[6][7][10]

History of substance use disorder

Oxybate is gamma-hydroxybutyrate (GHB), a substance with genuine, known abuse potential; evaluate patients for a history of drug abuse before prescribing, and monitor closely for signs of misuse (dose escalation on the patient's own initiative, drug-seeking behaviour).^[4][9] Stimulants carry a parallel caution, and combining modafinil with another CNS stimulant (amphetamines, methylphenidate) can produce additive blood pressure/heart rate increases and, specifically with dextroamphetamine, clinically important QTc prolongation — these combinations should not be taken at the same time.^[5]

Track functional outcome directly at every visit — the patient's actual ability to stay awake and engaged at school, at work, and while driving — not only a symptom count, since this is the outcome that determines both quality of life and driving eligibility.^[1]

For cataplexy on sodium oxybate or the lower-sodium oxybate salts: keep a cataplexy frequency diary and allow a full 8-10 weeks at an adequate, tolerated dose before judging maximal response.^[4] Monitor specifically for confusion (reported in a meaningful minority of treated patients, usually resolving with continued treatment or dose adjustment), for emergent depressive symptoms or suicidal ideation — a labelled concern, particularly in patients with a prior history of depression — and for parasomnia/sleepwalking and nocturnal urinary or fecal incontinence, all of which are recognized, dose-related adverse effects that should prompt evaluation rather than being dismissed as unrelated.^[4]

Patients on sodium oxybate or the lower-sodium oxybate salts should be seen regularly through the course of therapy — every 3 months is the interval recommended under the Controlled Distribution Program — with serious adverse events reported to the manufacturer as part of that program.^[4]

Monitor blood pressure and heart rate at initiation and periodically during treatment with modafinil, solriamfetol, methylphenidate, or dextroamphetamine, with closer monitoring in patients with any cardiovascular risk factor or renal impairment (solriamfetol specifically).^[5][6][7]

Driving fitness is an ongoing, not a one-time, assessment. A diagnosis of narcolepsy supported by a sleep study and MSLT is required before driving recommendations apply; driving all classes of motor vehicle is prohibited with any uncontrolled cataplexy, sleep attack, or sleep paralysis episode in the past 12 months, with or without treatment.^[3] Commercial driving carries a further caution, since long-distance driving is genuinely difficult without significant hypersomnolence; limited exceptions exist for short-route daytime driving in patients maintaining a regular sleep-wake cycle.^[3] Higher crash probability correlates with younger age, elevated subjective sleepiness scores, and concurrent psychiatric conditions — factors worth specifically asking about at follow-up.^[3] With sustained, effective treatment, many patients regain near-normal function and become eligible to drive once symptoms have been controlled for 12 months.^[1]

1. EDS inadequately controlled on modafinil monotherapy at the maximum tolerated dose (up to 400 mg/day, occasionally 500 mg with specialist oversight): switch to or add solriamfetol, since the two act through different mechanisms and lack of response to one does not predict lack of response to the other.^[5][6]
2. EDS still inadequate after trialling both first-line wake-promoting agents: in a Type 1 patient, sodium oxybate or the lower-sodium oxybate salts meaningfully improve EDS in practice even though their Canadian indication is specifically cataplexy — a reasonable next step before layering on a third wake-promoting agent; in a Type 2 patient, reassess the diagnosis and consider pitolisant, discussing the real Canadian reimbursement barrier directly with the patient.^[11]
3. Cataplexy inadequately controlled on venlafaxine or clomipramine alone: escalate to sodium oxybate or the lower-sodium oxybate salts, since these are the only Health Canada-approved cataplexy-specific therapies and carry the strongest evidence base for this symptom.^[4][8]
4. Sodium oxybate inadequate at the 9 g/night maximum after a full 8-10 week trial: consider adding a wake-promoting agent for residual EDS or an anticataplectic antidepressant for residual cataplexy, rather than exceeding the recommended maximum dose, which has not been studied and is not recommended.^[4]
5. Significant sodium-related comorbidity (hypertension, heart failure, chronic kidney disease) limiting further sodium oxybate titration: switch to the lower-sodium oxybate salts (92% less sodium at an equivalent dose) rather than abandoning oxybate therapy altogether, since it is the sodium load — not the oxybate itself — that is the limiting factor.^[9]
6. Persistent, functionally limiting EDS and/or cataplexy despite an optimized combination of agents: reassess the diagnosis directly — comorbid obstructive sleep apnea, chronic insufficient sleep, medication nonadherence, and untreated depression are all real, treatable contributors that can masquerade as treatment-refractory narcolepsy — and re-refer to sleep medicine.
7. New or worsening psychiatric symptoms emerging on any agent in this chapter: reassess causality specifically before adding a separate psychiatric medication; dose reduction, discontinuation, or a switch of the causative narcolepsy drug is often the correct first step.^[4][5]

• Assuming narcolepsy means only "falls asleep at random moments" and never asking specifically about triggered muscle weakness — many patients do not spontaneously volunteer cataplexy or even recognize it as part of the same condition.^[1]
• Diagnosing or ruling out narcolepsy from history and examination alone, without objective PSG-then-MSLT confirmation.^[1]
• Working up a dramatic cataplexy episode as a seizure or a faint because consciousness appears altered — it is fully preserved in cataplexy, and this is the key distinguishing feature.^[1]
• Prescribing or expecting modafinil to help cataplexy — its Canadian label states explicitly that it has no significant effect on cataplexy.^[5]
• Forgetting the contraceptive-efficacy interaction shared by modafinil, armodafinil, and pitolisant — an entirely preventable unplanned-pregnancy risk that pharmacist counseling should specifically address.^[5][8]
• Starting or transferring a prescription for sodium oxybate or the lower-sodium oxybate salts without confirming enrollment of the prescriber, pharmacy, and patient in the Controlled Distribution Program, or dispensing outside the single-wholesaler restricted-distribution chain.^[4][9]
• Co-dispensing or overlooking concurrent use of sodium oxybate/the lower-sodium oxybate salts with another sedative-hypnotic, opioid, or alcohol — an absolute contraindication given additive CNS and respiratory depression risk.^[4]
• Not counseling on the mandatory oxybate administration routine: take only at bedtime, do not walk around after dosing, prepare and take the second dose 2.5-4 hours later while already in bed, and avoid hazardous activity or driving for at least 6 hours after a dose.^[4]
• Overlooking that food significantly reduces oxybate bioavailability — a dose taken too close to a meal changes both efficacy and predictability of effect; patients should stop eating at least 2 hours before the first dose.^[4]
• Assuming standard sodium oxybate and the lower-sodium oxybate salts are interchangeable without adjustment for sodium-sensitive comorbidity, when the entire point of the lower-sodium formulation is to avoid that exact problem.^[9]
• Recommending pitolisant as a routine first choice in Canada without mentioning the real, documented non-reimbursement decision and cost.^[11]
• Skipping the driving-fitness conversation — a patient with current or recent symptoms should be counseled proactively, not only after an incident.^[3]

How to use this table: Doses are adult doses and require patient-specific confirmation (renal/hepatic function, weight, allergy history). Pediatric dosing is weight-based per the current product monograph unless stated. Drug pricing is intentionally omitted. Select any drug name to open its complete Pharmasist Drug Database page.

Wake-Promoting Agents and Stimulants for Excessive Daytime Sleepiness

Modafinil and solriamfetol are first-line, strongly recommended options with the lowest abuse-potential and cardiovascular burden of this group; methylphenidate and dextroamphetamine carry a genuine, current Canadian narcolepsy indication but a conditional recommendation and meaningfully greater cardiovascular/abuse-potential burden.

Oxybates for Cataplexy (Canadian Indication: Cataplexy, Not EDS)

Both products contain the same active moiety (oxybate/gamma-hydroxybutyrate, GHB) and share an identical Controlled Distribution Program; the lower-sodium formulation exists specifically to reduce cardiovascular/renal sodium burden without sacrificing efficacy.

Pitolisant — EDS and/or Cataplexy

The only agent in this chapter with a formal Health Canada indication for both excessive daytime sleepiness and cataplexy; discuss the real, current Canadian non-reimbursement decision and cost with patients before recommending it as a first choice.

Off-Label Anticataplectic Antidepressants

Widely used in practice given much faster onset than the oxybates and lower regulatory burden, but the AASM guideline made no formal recommendation for the SSRI/SNRI class specifically, citing insufficient/inconclusive trial-level evidence — set expectations with patients accordingly.