Meprodine is an opioid

Opioid

An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...

 analgesic

Analgesic

An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....

 that is an analogue

Analog (chemistry)

In chemistry, a structural analog , also known as chemical analog or simply analog, is a compound having a structure similar to that of another one, but differing from it in respect of a certain component. It can differ in one or more atoms, functional groups, or substructures, which are replaced...

 of pethidine

Pethidine

Pethidine or meperidine Pethidine (INN) or meperidine (USAN) Pethidine (INN) or meperidine (USAN) (commonly referred to as Demerol but also referred to as: isonipecaine; lidol; pethanol; piridosal; Algil; Alodan; Centralgin; Dispadol; Dolantin; Mialgin (in Indonesia); Petidin Dolargan (in Poland);...

 (meperidine). It is closely related to the drug prodine

Prodine

Prodine is an opioid analgesic that is an analogue of pethidine .There are two isomers of prodine, Alphaprodine and Betaprodine. Betaprodine is some 5x more potent than alphaprodine, but is metabolised more rapidly, and only alphaprodine was developed for medicinal use...

, the only difference being that meprodine has an ethyl group

Ethyl group

In chemistry, an ethyl group is an alkyl substituent derived from ethane . It has the formula -C2H5 and is very often abbreviated -Et.Ethylation is the formation of a compound by introduction of the ethyl functional group, C2H5....

 rather than a methyl at the 3-position of the piperidine

Piperidine

Piperidine is an organic compound with the molecular formula 5NH. This heterocyclic amine consists of a six-membered ring containing five methylene units and one nitrogen atom...

 ring.

As with prodine, there are two isomer

Isomer

In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...

s of meprodine, alpha-meprodine and beta-meprodine, with the alpha isomer having been more widely used.

Meprodine has similar effects to other opioids, and produces analgesia, sedation and euphoria. Side effects can include itching, nausea

Nausea

Nausea , is a sensation of unease and discomfort in the upper stomach with an involuntary urge to vomit. It often, but not always, precedes vomiting...

 and potentially serious respiratory depression which can be life-threatening.