A synthetic analgesic and antispasmodic drug, which is used in the treatment of painful and spasmodic conditions in place of morphine and atropine. A prompt but short-lasting analgesic, it has less of a constipating effect than morphine but is less potent. It is used for analgesia during childbirth because it produces less respiratory depression in the baby than other opioids. Pethidine is one of the controlled drugs.