Pethidine, usually referred to on House M.D. by its brand name Demerol(TM), is a fast acting narcotic painkiller. It is used for the treatment of moderate to severe pain and comes in pill form, syrup, or by injection. It was once very commonly used, particularly for the treatment of spasms. However, it is more rarely used now as it is no more effective than morphine in most cases and, although fast acting, also only acts for a short period of time compared to other narcotics.
Pethidine is also risky because of negative medicine interactions, such as MAOIs, anti-depressants, benzodiazepine, and alcohol. Among its side effects are constipation, dry mouth, twitching, and nausea.