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AIM: The growing demand for analgesia, coupled with an increasing need to treat opioid dependence and overdose, has escalated the development of novel opioids. We aimed to quantify the number of opioid drugs developed and to catalogue them based on their pharmacology. METHODS: We conducted a systematic search of seven sources in November 2020, including the WHO's Anatomical Therapeutic Classification index, the British National Formulary, the IUPHAR/BPS Guide to Pharmacology, the International Narcotics Control Board Index of Names of Narcotic Drugs, the WHO's International Nonproprietary Names MedNet service, Martindale's Extra Pharmacopoeia and the Merck Index, to include opioid drugs that targeted or had an effect or coeffect at one or more opioid receptors. We extracted chemical and nonproprietary names, drug stems, molecular formulas, molecular weights, receptor targets, actions at opioid receptors and classes based on their origins. We used descriptive statistics and calculated medians and interquartile ranges where appropriate. RESULTS: We identified 233 opioid drugs and created an online resource ( There were 10 unique drug stems, and "-fentanil" accounted for one-fifth (20%) of all opioids. Most of the drugs (n = 133) targeted mu-opioid receptors and the majority (n = 191) were agonists at one or more receptors. Most (82%) were synthetic opioids, followed by semisynthetic opioids (16%) and alkaloids (3%). CONCLUSION: This catalogue centralizes and disseminates information that could assist researchers, prescribers and the public to improve the safe use of opioids.

Original publication




Journal article


Br J Clin Pharmacol

Publication Date



catalogue of drugs, drug indexes, drug lists, narcotics, opiates, opioids