Nefopam, sold under the brand nameAcupan among others, is a centrally acting, non-opioidanalgesic medication, withstimulant andsympathomimetic properties that is primarily used to treat moderate to severepain.[3]
Nefopam is based on a benzoxazocine compound. It was developed in the 1960s and marketed under the name fenazocine.[4] It was initially used in shivering, as a muscle relaxant and as an antidepressant, but then increasingly as an analgesic.[4]
Nefopam was significantly more effective thanaspirin as an analgesic in one clinical trial,[5] although with a greater incidence of side effects such as sweating, dizziness and nausea, especially at higher doses.[6][7]
The estimated relative potency of nefopam to morphine indicates that 20 mg of nefopam HCl is the approximate analgesic equal of 12 mg of morphine with comparable analgesic efficacy to morphine,[8][9][10] oroxycodone.[11] Nefopam tends to produce fewer side effects, does not produce respiratory depression,[12] and has much lessabuse potential, and so is useful either as an alternative to opioid analgesics, or as an adjunctive treatment for use alongside opioids or other types of analgesics.[10][13]
A 2025 review, covering 17 studies, found that nefopam was an effective adjunctive postoperative analgesic with benefits in pain management, and correlated with a mean decrease in opioid consumption across the studies of 38%. Adverse effects were not discussed in detail in the included studies.[14]
Nefopam is thought to have some efficacy for treating (off-label) Parkinson's disease, in a similar fashion to those ofBupropion andMethylphenidate.[17]
Nefopam is effective for prevention of shivering during surgery or recovery from surgery.[18][19]
Dosage is normally 90-180mg per day. Maximum dose is regarded as 270mg/day.[20] One 1979 study found that a ceiling effect on post-operative pain relief occurred at 60mg/day.[21]
Common side effects include nausea, nervousness, dry mouth, light-headedness andurinary retention.[22] Less common side effects include vomiting, blurred vision, drowsiness, sweating, insomnia, headache, confusion, hallucinations, tachycardia, aggravation of angina and rarely a temporary and benign pink discolouration of the skin orerythema multiforme.[22]
Some side effects, such as feeling confused or hallucinating, are more likely in patients over 65 years old.[23][22]
Nefopam has been shown to haveanticholinergic properties[22] and has a score of 2 on the anticholinergic burden (ACB)[24] scale.[25]Anticholinergic drugs have caused concerns about cognitive decline in older people.[26]
Nefopam is used in the UK, under prescription only,[37] although some UK regions do not advise initiation of use.[38][39] It is used in France,[40] although some concerns have been raised.[41]
As of 2014 Nefopam was notFDA-approved in the US.[42]
^abcdefghijklmSanga M, Banach J, Ledvina A, Modi NB, Mittur A (November 2016). "Pharmacokinetics, metabolism, and excretion of nefopam, a dual reuptake inhibitor in healthy male volunteers".Xenobiotica; the Fate of Foreign Compounds in Biological Systems.46 (11):1001–1016.doi:10.3109/00498254.2015.1136989.PMID26796604.S2CID34603935.
^Tigerstedt I, Tammisto T, Leander P (December 1979). "Comparison of the analgesic dose-effect relationships of nefopam and oxycodone in postoperative pain".Acta Anaesthesiologica Scandinavica.23 (6):555–560.doi:10.1111/j.1399-6576.1979.tb01486.x.PMID397711.S2CID40976610.
^Kang P, Park SK, Yoo S, Hur M, Kim WH, Kim JT, et al. (January 2019). "Comparative effectiveness of pharmacologic interventions to prevent shivering after surgery: a network meta-analysis".Minerva Anestesiologica.85 (1):60–70.doi:10.23736/S0375-9393.18.12813-6.PMID30226340.S2CID52288008.
^Tigerstedt I, Tammisto T, Leander P (December 1979). "Comparison of the analgesic dose-effect relationships of nefopam and oxycodone in postoperative pain".Acta Anaesthesiologica Scandinavica.23 (6):555–560.doi:10.1111/j.1399-6576.1979.tb01486.x.PMID397711.
^Andre L, Gallini A, Montastruc F, Montastruc JL, Piau A, Lapeyre-Mestre M, et al. (December 2019). "Association between anticholinergic (atropinic) drug exposure and cognitive function in longitudinal studies among individuals over 50 years old: a systematic review".European Journal of Clinical Pharmacology.75 (12):1631–1644.doi:10.1007/s00228-019-02744-8.PMID31468067.S2CID201675824.
^abBismuth C, Fournier PE, Bavoux E, Husson O, Lafon D (September 1987). "[Chronic abuse of the analgesic nefopam (Acupan)]".Journal de Toxicologie Clinique et Expérimentale (in French).7 (5):343–346.PMID3448182.
^Roth BL, Driscol J."PDSP Ki Database".Psychoactive Drug Screening Program (PDSP). University of North Carolina at Chapel Hill and the United States National Institute of Mental Health. Retrieved14 August 2017.
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