Modafinil (Provigil) — Eugeroic / Wakefulness Agent — Brain
FDA-approved eugeroic for narcolepsy, shift work disorder, and obstructive sleep apnea. Widely used off-label as a cognitive enhancer.
Overview
Modafinil is a eugeroic (wakefulness-promoting) agent FDA-approved for the treatment of excessive sleepiness associated with narcolepsy, obstructive sleep apnea/hypopnea syndrome (OSAHS), and shift work sleep disorder. Developed by Laboratoire Lafon in France and approved by the FDA in 1998, modafinil has become one of the most widely used cognitive enhancers worldwide. Its mechanism of action is not fully understood but involves inhibition of dopamine reuptake through the dopamine transporter (DAT), increasing extracellular dopamine in specific brain regions including the nucleus accumbens, prefrontal cortex, and orexin/hypocretin neurons of the lateral hypothalamus. Unlike traditional stimulants (amphetamines, methylphenidate), modafinil produces wakefulness without significant peripheral sympathetic activation, jitteriness, or the pronounced euphoria associated with high abuse potential. Multiple RCTs have demonstrated improvements in sustained attention, executive function, and working memory in sleep-deprived individuals. In well-rested individuals, cognitive enhancement effects are more modest and inconsistent. Modafinil is classified as Schedule IV by the DEA, acknowledging its lower (but non-zero) abuse potential. Common side effects include headache, nausea, insomnia, and reduced appetite. Rare but serious reactions include Stevens-Johnson syndrome and drug reaction with eosinophilia.
Indications
- FDA-approved: Narcolepsy
- FDA-approved: Obstructive sleep apnea/hypopnea syndrome (adjunct to CPAP)
- FDA-approved: Shift work sleep disorder
- Off-label: Cognitive enhancement in healthy individuals
- Off-label: ADHD (second-line)
- Off-label: Fatigue in multiple sclerosis, depression-related fatigue
Mechanism of Action
Modafinil binds the dopamine transporter (DAT), inhibiting dopamine reuptake and increasing extracellular dopamine concentrations in the prefrontal cortex and nucleus accumbens
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Modafinil | 100 mg | Once daily (morning) | Starting dose; sufficient for many users |
| Modafinil | 200 mg | Once daily (morning) | Standard FDA-approved dose for narcolepsy/OSAHS |
| Modafinil | 200 mg | 1 hour before shift (SWSD) | Shift work sleep disorder dosing |
| Modafinil | 400 mg | Once daily | Maximum dose — minimal additional benefit over 200 mg |
Evidence Grade
GRADE A
Safety & Contraindications
- Headache (34%), nausea (11%), and insomnia most common side effects
- Rare: Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS syndrome — discontinue at first sign of rash
- May reduce efficacy of hormonal contraceptives (CYP3A4 induction)
- Schedule IV controlled substance — lower but real abuse potential
- Insomnia if taken too late in the day (half-life 12-15 hours)
- Anxiety and overstimulation at higher doses
- Modest cardiovascular effects: slight BP and HR increase