"Serious" Adverse Drug Reactions with Tramadol: a 2010-2011 Pharmacovigilance Survey in France

Objective. Tramadol is a weak opioid used as a step 2 analgesic, approved in France for moderate to severe pain. After dextropropoxyphene withdrawal, a national pharmacovigilance follow-up of tramadol was decided by the French Drug Agency. Methods. All Serious Adverse Drug Reactions (SADR) notified with tramadol to the French PharmacoVigilance Centres (CRPV) and pharmaceutical companies between August 1st, 2010 and July 31th, 2011 were analyzed. Results. During the study period, 296 cases of SADR were notified to CRPV and 59 to pharmaceutical companies. Apart from opiate-related SADR, tramadol induced serotoninergic SADR, including seizures or serotoninergic syndromes. Several "unlabelled" SADR were also identified: some of them, like hyponatremia or hypoglycemia, are poorly known by health professionals. Other were never published: peripheral edema or pancreatitis. Conclusion. This study shows that besides well-known opioid or serotoninergic ADR, tramadol can also induce 2 other relatively unknown ADR: hypoglycemia and hyponatremia.