Modafinil is an FDA-approved drug manufactured by Sun Pharma Ltd. that stimulates orexin receptors and increases hormones like dopamine, norepinephrine, histamine, and serotonin to promote wakefulness, enhance cognition, and treat sleep disorders while reducing depression and fatigue. Possible side effects include headache, nausea, and anxiety, and it should be avoided by those with cardiac, renal, hepatic, or substance abuse issues, as well as pregnant or breastfeeding women.