Modafinil
A prescription wakefulness-promoting agent approved for narcolepsy, obstructive sleep apnoea and shift-work sleep disorder. It reliably reduces sleepiness and is among the most rigorously studied off-label cognitive enhancers, with modest but replicable effects on alertness and some executive functions.
01 Overview
Modafinil was developed in France in the 1970s-80s and approved by the FDA in 1998 for narcolepsy. It promotes wakefulness with a lower profile of peripheral sympathetic stimulation than classical amphetamines, and is widely used off-label for shift work, jet lag and cognitive enhancement.
Controlled trials in sleep-deprived and non-sleep-deprived adults show consistent improvements in vigilance and sustained attention, with smaller and more variable effects on higher-order cognition. It is generally well tolerated, though headache, nausea and insomnia are common, and rare serious rashes have been reported.
02 Mechanism
Primarily blocks the dopamine transporter (DAT), raising extracellular dopamine, and modulates orexin, histamine, noradrenaline and glutamate/GABA systems to promote cortical arousal.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Standard therapeutic | 100–200 mg/day | Oral | Usually taken once in the morning; 200 mg is the approved daily dose for most indications. |
| Upper range | 200–400 mg/day | Oral | 400 mg has not shown consistent added benefit over 200 mg in trials. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Reduced sleepiness / increased wakefulnessRobustly restores alertness during sleep deprivation and in sleep disorders. | Large in sleep-deprived states | Clinical | |
| Improved sustained attentionEnhances vigilance and reaction time, most reliably when fatigued. | Small-to-moderate | Clinical | |
| Modest executive-function gainsSome improvement in planning and working memory in rested individuals, with inconsistent findings across tasks. | Small, variable | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| HeadacheDose-related headache reported in a large fraction of users. | Mild | Most common adverse effect | Clinical | |
| InsomniaDifficulty sleeping, especially with late dosing. | Moderate | Common | Clinical | |
| Serious skin reactions (SJS/DRESS)Stevens-Johnson syndrome and hypersensitivity reactions have been reported, prompting a boxed warning in paediatric use. | Life-threatening | Rare but serious | Clinical |