Maximum Dose of Modafinil
The maximum recommended dose of modafinil is 400 mg per day, administered either as a single morning dose or divided into morning and midday doses. 1, 2
Standard Dosing Protocol
- Starting dose: Begin with 200 mg once daily in the morning 3
- Dose escalation: Can be increased to 400 mg daily if needed for symptom control 1, 2
- Maximum daily limit: Do not exceed 400 mg per day 4, 1
- Timing of administration: Give as single morning dose OR split into morning and midday doses 1
- Last dose timing: Final dose should be no later than 2:00 PM to avoid insomnia 2
Special Population Considerations
Elderly Patients
- Initial dose: Start with 100 mg once upon awakening 1, 3
- Titration: Increase at weekly intervals as necessary 1, 3
- Maintenance range: Typical maintenance is 200-400 mg per day 3, 2
Dose Selection Based on Clinical Indication
The evidence suggests different dosing strategies depending on the primary symptom:
- For excessive daytime sleepiness: Higher doses (200-400 mg/day) are more effective 1
- For concentration problems and fatigue: Lower doses (50-200 mg/day) may be more appropriate 1
Time to Therapeutic Effect
- Half-life: Approximately 15 hours 1, 3, 2
- Steady state: Reached after 2-4 days of dosing 1, 3, 2
- Peak plasma concentration: Occurs 2-3 hours after oral administration 3
Common Pitfalls to Avoid
- Late dosing: Administering modafinil too late in the day can cause insomnia; ensure the last dose is before 2:00 PM 2
- Exceeding maximum dose: Doses above 400 mg/day are not recommended and do not provide additional benefit 1, 2
- Inadequate monitoring: Monitor blood pressure, heart rate, and cardiac rhythm when initiating or adjusting doses 3, 2
Important Safety Considerations
- Common adverse effects: Headache (34%), nausea (11%), nervousness, insomnia, back pain, and dyspepsia 1, 3, 5
- Cardiovascular monitoring: Assess for hypertension, palpitations, and arrhythmias during dose adjustments 3
- Contraceptive interaction: Modafinil reduces efficacy of hormonal contraceptives; alternative contraception methods are required 2
- Rare but serious: Stevens-Johnson syndrome is a rare but life-threatening complication requiring immediate discontinuation if rash develops 1
Clinical Context
Multiple large-scale studies demonstrate that modafinil 200-400 mg/day is well tolerated, with the majority of adverse events being mild to moderate in nature 5, 6. In clinical trials, approximately 70% of patients required 400 mg daily for optimal symptom control 6, 7. The drug maintains its tolerability profile even with long-term use up to 40 weeks 1.