Sleep is essential for optimal mental, physical and social wellbeing (or, generically, health). Sleep disruption and/or deprivation can have adverse health consequences, promoting or worsening cardiovascular disease and diabetes. Sleep-wake regulation depends on complex interactions between multiple brain regions. Many medications can have direct or indirect effects on these sleep-wake regulation regions and thus may promote sleepiness, insomnia or sleep disruption. We will review briefly the impact of commonly used medications on the sleep-wake cycle.