Viminol (marketed under the brandname Dividol) is an opioid analgesic developed by a team at the drug company Zambon in the 1960s.[2] Viminol is based on the α-pyrryl-2-aminoethanol structure, unlike any other class of opioids.[3][4]

Viminol has both antitussive (cough suppressing) and analgesic (pain reducing) effects. Viminol has additional effects similar to other opioids including sedation and euphoria.[citation needed] It has six different stereoisomers which have varying properties. Four are inactive, but the 1S-(R,R)-disecbutyl isomer is a μ-opioid full agonist around 5.5 times more potent than morphine and the 1S-(S,S)-disecbutyl isomer is an antagonist.[5][6] Since vimonol is supplied as a racemic mixture of isomers, the overall effect is a mixed agonist–antagonist profile similar to that of opioids such as pentazocine, although with somewhat fewer side effects.[7]

Side effects
Side effects are similar to other opioids, and can include:[medical citation needed]
Itching
Nausea
Sedation
Respiratory depression - can be potentially life-threatening
However, since viminol is supplied as a racemic mixture of agonist and antagonist isomers, the abuse potential and respiratory depression tends to be less than that of μ-opioid full agonist drugs.

Related compounds
Later work showed that replacing the chlorine atom with an fluorine atom or with a trifluoromethyl group produced a compound with twice the potency and half the acute toxicity.[9] A later team at Zambon found that one isomer of a pyrrolidone analog is 318 times as potent as morphine in its analgesic activity in animal studies.[10] A number of related compounds were also found to be active, allowing a QSAR model to be constructed.