Modafinil dosage

Protocol

1. 1

   Measure the dose

   Typical Modafinil dose is 200 mg (Approved doses: 200 mg morning for narcolepsy and OSA; 200 mg one hour pre-shift for shift work). Use a weight-based calculator for individual adjustments.

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2. 2

   Set the frequency

   Administer daily, morning. Half-life of 13 hours anchors the dosing interval.

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3. 3

   Cycle if needed

   No formal cycling required for approved indications; long-term safety in narcolepsy documented over years

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4. 4

   Monitor for side effects

   Watch for: headache; nausea; anxiety; insomnia (with late-day dosing). Stop or reduce dose if tolerability breaks down.

Why this dose

Weak dopamine reuptake inhibition plus downstream activation of histaminergic, noradrenergic, and orexinergic wake-promoting systems.

The typical dose (200 mg) reflects Approved doses: 200 mg morning for narcolepsy and OSA; 200 mg one hour pre-shift for shift work. Individual response varies with body weight, baseline status, concurrent training, and concurrent medications, so the labeled range is the starting point rather than the prescription.

How to administer

Modafinil is administered via the oral route. Oral dosing is straightforward: take with water, with or without food unless specifically noted.

Onset of action runs around 1 hour after administration. Peak effect lands near 3 hours post-dose. Plan the administration window so that peak effect lines up with whatever outcome you are dosing for, whether that is training, sleep, or symptom coverage.

Half-life note: Terminal half-life 12 to 15 hours; longer in CYP2C19 slow metabolizers

Cycling and tolerance

No formal cycling required for approved indications; long-term safety in narcolepsy documented over years

Effects to expect at typical dose

• FDA approved in 1998 for narcolepsy, with later additions for shift-work sleep disorder and OSA residual sleepiness
• Schedule IV controlled substance in the US; prescription-only in EU, UK, Australia
• Increases wakefulness via weak dopamine reuptake inhibition plus histaminergic, noradrenergic, and orexinergic activation
• Long half-life of 12 to 15 hours requires morning dosing to avoid sleep disruption
• Modest cognitive enhancement signal in non-sleep-deprived adults at 100 to 200 mg (Battleday meta-review 2015)
• Substantial CYP3A4 induction reduces hormonal contraceptive efficacy; barrier methods recommended

Side effects and interactions

Common side effects

• headache
• nausea
• anxiety
• insomnia (with late-day dosing)
• dry mouth

Notable interactions

• hormonal contraceptives (major): CYP3A4 induction reduces contraceptive efficacy; use barrier method
• cyclosporine (major): reduced cyclosporine levels via CYP3A4 induction
• MAOIs (major): potential hypertensive reaction
• warfarin (moderate): CYP2C9 inhibition raises INR
• phenytoin (moderate): CYP2C19 inhibition raises phenytoin levels

Lists above cover commonly reported and well-characterized items. They are not exhaustive: review the full Modafinil profile and discuss with a clinician familiar with your medication list before starting, particularly if you are on prescription therapy or have a chronic condition.

Regulatory snapshot

WADA status

banned

DEA / Rx

Schedule IV

Pregnancy

Not recommended

Legal status

Schedule IV (US); prescription-only globally; not a supplement

Do not use if

• recent myocardial infarction
• unstable angina
• left ventricular hypertrophy
• significant arrhythmia
• history of Stevens-Johnson syndrome
• psychotic disorders
• pregnancy
• concurrent MAOI use

Related research