Propylketobemidone 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 ketobemidone

Ketobemidone

Ketobemidone is a powerful opioid analgesic. Its effectiveness against pain is in the same range as morphine, and it also has some NMDA-antagonist properties imparted by it's metabolite norketobemidone. This makes it useful for some types of pain that don't respond well to other opioids...

. It was developed in the 1950s during research into analogues 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);...

 and was assessed by the United Nations Office on Drugs and Crime

United Nations Office on Drugs and Crime

The United Nations Office on Drugs and Crime is a United Nations agency that was established in 1997 as the Office for Drug Control and Crime Prevention by combining the United Nations International Drug Control Program and the Crime Prevention and Criminal Justice Division in the United Nations...

 but was not included on the list of drugs under international control, probably because it was not used in medicine or widely available.

Propylketobemidone is so named because it is the propyl

Propyl

In organic chemistry, propyl is a three-carbon alkyl substituent with chemical formula -C3H7. It is the substituent form of the alkane propane...

 ketone

Ketone

In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

 analogue of bemidone (hydroxypethidine). The more commonly used ethyl ketone ("ethylketobemidone") is simply called ketobemidone, as it is the only drug of this family to have been marketed.

Presumably propylketobemidone produces similar effects to ketobemidone and other opioids, such as analgesia and sedation

Sedation

Sedation is the reduction of irritability or agitation by administration of sedative drugs, generally to facilitate a medical procedure or diagnostic procedure...

, along with side effects such as 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...

, itching, vomiting

Vomiting

Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...

 and respiratory depression which may be harmful or fatal.