High Quality Content by WIKIPEDIA articles! Propiomazine (Largon, Propavan, Indorm, Serentin, Indorm, Dorevane, Dorevan) is an antihistamine blocking H1 receptors. It is used to treat insomnia, and to produce sleepiness or drowsiness and to relieve anxiety before or during surgery or other procedures and in combination with analgetics also during labor. Propiomazine is a phenothiazine, but is not used as a neuroleptic because it does not block dopamine receptors well.