Somnolence is a state of sleepiness close to falling asleep. Many psychiatric medications (and many non-psychiatric medications, too) can cause somnolence, which is one reason why there are so many warnings about not driving or operating heavy machinery until you know how a medicine will affect you.
If you are concerned that one of the medications you, a loved one or friend are taking, or want to know whether a medication under consideration can cause somnolence, visit our Side Effects Library.
Adjective: somnolent

