Does memantine induce bradycardia? A study in the French PharmacoVigilance Database.

Objective: To review the cardiovascular adverse drug reactions (ADRs) with memantine reported to the French PharmacoVigilance Database.
Methods: We reviewed all the observations of cardiovascular ADRs with memantine reported to the French PharmacoVigilance Database up to May 2007. We recorded the characteristics of patients (age, sex and underlying disease) and of ADRs (nature, seriousness, delay in occurrence, evolution, imputability).
Results: After exclusion of 16 cases, the cardiac origin of which was not clearly assessed, 36 cardiac ADRs with memantine were recorded between its commercialisation in France (July 2003) and May 2007. These ADRs consisted of 18 reports of bradycardia and 18 reports of various cardiovascular ADRs (orthostatic hypotension with fall[6] electrocardiogram perturbations[4] fainting[2] malaise with arterial hypotension[2] arterial hypotension and acute renal failure[1] fatal heart failure[1] sudden death[2]). Among the 18 reports of bradycardia, 7 cases occurred with memantine as the sole suspected drug and all but one resolved after memantine's discontinuation.
Conclusion: Cardiovascular properties of memantine seem to be complex and remain quite unclear. Despite its drawbacks and its descriptive design, our study suggests that memantine could determine some cardiac ADRs, especially bradycardia; the mechanism of which remains unexplained.