Modafinil, sold under the brand name Provigil among others, is a central nervous system (CNS) stimulant medication used to treat sleepiness due to narcolepsy, shift work sleep disorder, and obstructive sleep apnea. While it has seen off-label use as a purported cognitive enhancer to improve wakefulness in animal and human studies, the research on its effectiveness for this use is not conclusive. Modafinil is taken by mouth.
Modafinil's side effects include headaches, anxiety, excessive adrenal gland overproduction, and nausea. Serious side effects in high doses include delusions, unfounded beliefs, paranoia, irrational thought, and transient depression, possibly due to its effects on dopamine receptors in the brain, as well as allergic reactions. The amount of medication used should be adjusted in those with kidney problems, as this medication has markedly increased side effects during renal insufficiency.