Ten years of adverse drug reaction reports for the multiple sclerosis immunomodulatory therapies: a Canadian perspective

Adverse drug reaction (ADR) reporting is essential in the post-marketing surveillance of drugs, detection of serious adverse reactions, and has been the basis for drug withdrawals. The study aimed to examine ADR reporting patterns to the multiple sclerosis (MS) immunomodulatory drugs (IMD) in Canada. All ADRs reported to the Canadian ADR Monitoring Program (CADRMP) from 1965 to March 2006 (n = 193 208) were accessed and ADRs in which an IMD for MS (beta- interferon or glatiramer acetate) was the suspected drug extracted (n = 888 reports were dated March/96-March/06). Almost half of all IMD ADRs reports (438/888) were sourced through the patient compared to 14.9% (10 649/71 373) of all ADRs reported to CADRMP over the same period. Of IMD ADR reports, 88.7% (788/888) were directed through the manufacturer compared to 57.7% (41197/71373) of all ADRs. Encouragement to others involved in patient care, such as pharmacists, nurses and physicians might enhance reporting of MS ADRs. Despite the limitations of ADR reporting data, previously unpublished case reports in several understudied MS populations were detailed: paediatrics (<= 16 years old, n = 4), the elderly (>= 65 years, n = 23) and during pregnancy (n = 12). In addition, 46 deaths suspected by the reporter as being related to IMD treatment were detailed as well as three possible drug interactions.