Pethidine

Pethidine (INN) or meperidine hydrochloride (USAN) (commonly referred to as Demerol in the US but also referred to as: isonipecaine; lidol; pethanol; piridosal; Algil; Alodan; Centralgin; Dispadol; Dolantin; Mialgin (in Indonesia); Petidin Dolargan (in Poland); Dolestine; Dolosal; Dolsin; Mefedina) is a fast-acting opioid analgesic drug.

Pethidine was the first synthetic opioid synthesized in 1932 as a potential anti-spasmodic agent by the chemist Otto Eislib. Its analgesic properties were first recognized by Otto Schaumann working for IG Farben, Germany.

Pethidine is indicated for the treatment of moderate to severe pain, and is delivered as a hydrochloride salt in tablets, as a syrup, or by intramuscular, subcutaneous or intravenous injection. For much of the 20th century, pethidine was the opioid of choice for many physicians; in 1975 60% of doctors prescribed it for acute pain and 22% for chronic severe pain.

Compared to morphine, pethidine was supposed to be safer and carry less risk of addiction, and to be superior in treating the pain associated with biliary spasm or renal colic due to its putative antispasmodic effects. In fact, pethidine is no more effective than morphine at treating biliary or renal pain, and its low potency, short duration of action, and unique toxicity (i.e., seizures, delirium, other neuropsychological effects) relative to other available opioid analgesics have seen it fall out of favor in recent years for all but a very few, very specific indications. Several countries, including Australia, have put strict limits on its use. Nevertheless, some physicians continue to use it as a first line strong opioid.