A class of drugs all of which produce drowsiness
and are prescribed most frequently in cases of insomnia. All these drugs
function similarly to depress, no selectively, central nervous system
functioning. Depending on the size of the dose, they produce mild sedation,
"hypnotic" sleep, anesthesia, coma, and death from respiratory failure. All are
subject to buildup of tolerance, so that increasing doses are needed to maintain
the same effect, and all produce drug dependence. They also diminish
sensory-motor skills and interact strongly with many other drugs, significantly
alcohol. Other drugs are occasionally included in the category of sedatives, in
particular antihistamines, which have drowsiness as a side-effect, and some
tranquilizers,
which may aid
sleep by reducing anxiety and agitation.