Phenoperidine is an opioid analgesic partly metabolized to meperidine in the liver. It is derived from pethidine by replacing the N methyl by a phenyl propanol chain. It is reputed to be a typical morphine-like analgesic characterized by its high potency, rapid onset of action, the intensity of its peak effect and the short duration of its pharmacological effects. It is used in general anesthesia.

Phenoperidine:
https://drugs.ncats.io/drug/G9BH09J4JW

Phenoperidine (HCl) is a narcotic analgesic, used to relieve moderate to severe pain. Phenoperidine (HCl) is used with droperidol to produce neuroleptanalgesia (a state of consciousness with calmness allowing the patient to co-operate with surgeon). It is of Synthetic origin and belongs to Opioid. It belongs to OPIATE agonist pharmacological group on the basis of mechanism of action and also classified in General Anesthetics and Analgesic-Narcotic pharmacological group.

Indications:
Phenoperidine (HCl) is primarily indicated in conditions like Pain, and can also be given in adjunctive therapy as an alternative drug of choice in Anesthesia, Surgery.

Contraindications:
Phenoperidine (HCl) is contraindicated in conditions like Renal diseases, Respiratory disease, Hepatic disease.

Side Effects:
Phenoperidine (HCl) produces potentially life-threatening effects which include Respiratory depression, Severe Hypotension. which are responsible for the discontinuation of Phenoperidine (HCl) therapy.

The signs and symptoms that are produced after the acute overdosage of Phenoperidine (HCl) include Cyanosis, Cardiac arrest.

Phenoperidine (HCl) Monograph:
http://www.druginfosys.com/drug.aspx?drugCode=564&type=1

• An opioid pain killer.
• Used clinically as a general anesthetic.
• Structurally related to pethidine.
• It is a derivative of isonipecotic acid, like pethidine, and is metabolized in part to norpethidine.
• 20-80 times as potent as pethidine as an analgesic.

The greatly increased potency essentially eliminates the toxic effects of norpethidine accumulation which are seen when pethidine is administered in high doses or for long periods of time.

• Phenoperidine was first synthesized in 1957 by Paul Janssen, of the company now known as Janssen Pharmaceutica, who was seeking better opioid pain-killers.

During his explorations, he replaced the methyl group attached to the pethidine nitrogen with a propiophenone group, and this yielded phenoperidine, in 1957. Phenoperidine was determined to have decreased stability and enhanced lipophilicity compared to pethidine. Soon after, studies in mice showed that phenoperidine was over 100 times more potent than pethidine. Through further advances, Janssen created fentanyl in 1960, which proved to be ten times more potent than phenoperidine.

In 1959, the combination of phenoperidine and haloperidol was first used in Europe in anesthesia to induce a detached, pain free state called Neuroleptic analgesia; the use of that mixture boomed in early 1960s but was overtaken by the combination of fentanyl and droperidol, which was widely used through the 1980s. These combination approaches were not adopted in the US.