Alfentanil (R-39209, trade name Alfenta, Rapifen in Australia) is a potent but short-acting synthetic

opioid Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...

analgesic An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It ...

drug A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drugs are typically distinguished from food and substances that provide nutritional support. Consumption of drugs can be via inhala ...

, used for anaesthesia in

surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pa ...

. It is an analogue of

fentanyl Fentanyl, also spelled fentanil, is a very potent synthetic opioid used as a pain medication. Together with other drugs, fentanyl is used for anesthesia. It is also used illicitly as a recreational drug, sometimes mixed with heroin, cocain ...

with around one-fourth to one-tenth the potency, one-third the duration of action, and an onset of action four times faster than that of fentanyl. Alfentanil has a pKa of approximately 6.5, which leads to a very high proportion of the drug being uncharged at physiologic pH, a characteristic responsible for its rapid onset. It is an agonist at mu opioid receptors. While alfentanil tends to cause fewer cardiovascular complications than other similar drugs such as

and

remifentanil Remifentanil is a potent, short-acting synthetic opioid analgesic drug. It is given to patients during surgery to relieve pain and as an adjunct to an anaesthetic. Remifentanil is used for sedation as well as combined with other medications fo ...

, it tends to give stronger

respiratory depression Hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate (''hypo'' meaning "below") to perform needed respiratory gas exchange. By definition it causes an increased concentration of carbon dioxide (hypercapni ...

and so requires careful monitoring of breathing and vital signs. Almost exclusively used by anesthesia providers during portions of a case where quick, fast-acting (though not long-lasting) pain control is needed (as, for example, during nerve blocks), alfentanil is administered by the

parenteral A route of administration in pharmacology and toxicology is the way by which a drug, fluid, poison, or other substance is taken into the body. Routes of administration are generally classified by the location at which the substance is applied. ...

(injected) route for fast onset and precise control of dosage. Discovered at Janssen Pharmaceutica in 1976, alfentanil is classified as a Schedule II drug in the United States. Side effects of

analogs are similar to those of fentanyl itself and include

itching Itch (also known as pruritus) is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to be classified as any one type of sensory experience. Itch has many similarities to pain, and while both are unpleasan ...

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of th ...

and potentially life-threatening

. Fentanyl analogs have killed hundreds of people throughout Europe and the former Soviet republics since the most recent resurgence in use began in Estonia in the early 2000s, and novel derivatives continue to appear.

References

External links

Medline Plus Patient Information - 09/01/2010
* https://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/DrugInteractionsLabeling/ucm093664.htm February 2017 * Genf interaction table- https://www.hug.ch/sites/interhug/files/structures/pharmacologie_et_toxicologie_cliniques/carte_cytochromes_2016_final.pdf February 2017 {{Opioidergics General anesthetics Synthetic opioids Piperidines Tetrazoles Ureas Ethers Lactams Anilides Mu-opioid receptor agonists Janssen Pharmaceutica Belgian inventions Fentanyl