R-4066 is a drug which 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 the 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 ....

 methadone

Methadone

Methadone is a synthetic opioid, used medically as an analgesic and a maintenance anti-addictive for use in patients with opioid dependency. It was developed in Germany in 1937...

, where the metabolically labile dimethylamino group has been replaced by a piperidinospiro group. Developed by Janssen Pharmacutica, it is around 212x more potent than methadone as an analgesic in animal tests, with an effective oral dosage of 0.07mg/kg, but is slightly shorter acting, with a duration of action of around 3 hours.

R-4066 has never been used in humans, but would be expected to produce effects similar to those of other potent opioid agonists, including strong analgesia, sedation

Sedation

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

, euphoria

Euphoria (emotion)

Euphoria is medically recognized as a mental and emotional condition in which a person experiences intense feelings of well-being, elation, happiness, ecstasy, excitement and joy...

, constipation

Constipation

Constipation refers to bowel movements that are infrequent or hard to pass. Constipation is a common cause of painful defecation...

, itching and respiratory depression which could be harmful or fatal.