Overview of adverse reactions to nefopam: an analysis of the French Pharmacovigilance database

Nefopam is widely used for the relief of moderate acute pain. Its safety profile remains to be specified. The objective of the study was to review adverse reactions to nefopam spontaneously reported to the French Pharmacovigilance system. All cases of adverse drug reactions (ADRs) associated with nefopam, registered in the French Pharmacovigilance database from January 1, 1995 to December 31, 2004, were reviewed. For each reported ADR, information about patient (age, gender, medical history), drug exposure (suspected and concomitantly used drugs), characteristics of ADRs (imputability score, time of onset, seriousness, outcome) were collected. A total of 114 ADRs with an imputability rated from 'plausible' (I2) to 'likely' (I3) and 'very likely' (I4) was analysed. The most frequent ADRs included 'expected' ADRs such as sweating, nausea, tachycardia, malaise or vomiting; 61 ADRs were 'unexpected. No overdose was reported; 26 ADRs (23%) were considered as 'serious'. Most of them were 'unexpected', including neuropsychiatric (hallucinations, convulsions) or cutaneous (pruritus, erythema, urticaria) ADRs. Six cases of anaphylactic ADRs (two angioedema and four anaphylactic shocks) were reported, all occurring shortly after use of nefopam during the post-operative period. Physicians should be aware of the possible occurrence of some serious ADRs when using nefopam such as convulsions and anaphylactic shocks, especially when the drug is used in special medical conditions, like post-operative periods.