Which medication is known to have a sedative effect and is often used in sleep studies?

Diphenhydramine is recognized for its sedative properties and is commonly used in sleep studies due to its ability to induce drowsiness. As an antihistamine, it blocks the action of histamine in the body, which can produce sedation. This makes it useful for assessing sleep patterns and responses during polysomnography, where the goal is often to facilitate sleep or monitor sleep disturbances.

Melatonin, while involved in regulating sleep-wake cycles, does not have the same immediate sedative effects as diphenhydramine. Alprazolam is a benzodiazepine that also produces sedation but is less frequently used in a sleep study context due to its potential for dependency and the complexity it adds to interpreting sleep architecture. Fluoxetine, an SSRI, is used for anxiety and depression and does not have a sedative effect, making it unsuitable for promoting sleep in these studies.