Maximum Dosage for Modafinil
The maximum total daily dose of modafinil is 400 mg per day, typically administered as a single dose in the morning or divided into two doses. 1, 2
FDA-Approved Dosing
- The FDA-recommended dosage for narcolepsy or obstructive sleep apnea (OSA) is 200 mg once daily in the morning 3
- For shift work disorder (SWD), the recommended dose is 200 mg taken approximately one hour prior to the start of the work shift 3
- While 200 mg is the standard dose, clinical guidelines indicate that doses up to 400 mg daily are considered safe and effective for treating excessive sleepiness 1, 2
Dosing Considerations for Special Populations
- For patients with severe hepatic impairment, the dose should be reduced to half the recommended dose 3
- For elderly patients, a starting dose of 100 mg once upon awakening is recommended, with potential increases at weekly intervals as necessary 1, 2
- Lower doses may be more appropriate for certain indications - 50-200 mg/day may be more suitable for concentration problems and fatigue, while 200-400 mg/day may be more effective for treating sleepiness 1
Pharmacokinetic Considerations
- Modafinil has a half-life of approximately 15 hours 1, 4
- Steady state is typically reached after 2-4 days of dosing 1, 4
- The pharmacokinetics of modafinil are dose-independent between 200 and 600 mg/day 4
Safety Profile
- Most common adverse effects (≥5%) include headache, nausea, nervousness, rhinitis, diarrhea, back pain, anxiety, insomnia, dizziness, and dyspepsia 2, 3
- In clinical studies, modafinil was well-tolerated with adverse events similar to placebo except for headache (34% vs 23%) and nausea (11% vs 3%) 5
- Modafinil has less abuse potential compared to traditional stimulants like amphetamines 1, 2
Important Considerations
- Modafinil is classified as a federally controlled substance (C-IV) due to potential for abuse, though this risk is lower than with traditional stimulants 2, 3
- Unlike other psychostimulants, modafinil is not associated with withdrawal phenomena after treatment cessation 6
- Modafinil may reduce the efficacy of hormonal contraceptives; alternative or additional contraceptive methods should be used during treatment and for one month after discontinuation 3
Remember that exceeding the maximum recommended dose of 400 mg per day is not advised, as higher doses have not demonstrated increased efficacy and may increase the risk of adverse effects.