Complementary and alternative medicine: Pharmacovigilance in Malaysia and predictors of serious adverse reactions

WHAT IS KNOWN AND OBJECTIVE: Complementary and alternative medicine (CAM) is widely used worldwide for health maintenance, disease prevention and treatment. The objective of the study was to identify adverse drug reactions (ADR) associated with the use of CAM in Malaysia and factors which are associated with the more serious reactions.

METHODS: All ADR associated with the use of CAM products (including health supplements) submitted to the Malaysian Centre for ADR Monitoring, National Pharmaceutical Regulatory Agency over a 15-year period were reviewed and analysed. Multivariate logistic regression analysis was performed to identify predictors of serious ADR.

RESULTS AND DISCUSSION: From a total of 74 997 reports in the database, 930 (1.2%) involved CAM products, and 242 (26%) were serious with 36 deaths. About a third of the reports involved used CAM products for health maintenance. Most (78.1%) of the ADR reports implicated unregistered products with 16.7% confirmed to contain adulterants which were mainly dexamethasone. Of the 930 reports, the ADR involved skin and appendages disorders (18.4%) followed by liver and biliary system disorders (13.7%). The odds of someone experiencing serious ADR increased if the CAM products were used for chronic illnesses (odds ratio [OR] 1.99, confidence interval [CI] 1.46-2.71), having concurrent diseases (OR 1.51, CI 1.04-2.19) and taking concurrent drugs (OR 1.44, CI 1.03-2.02).

WHAT IS NEW AND CONCLUSIONS: The prevalence of serious ADR associated with CAM products is high. Factors identified with serious ADR included ethnicity, CAM users with pre-existing diseases, use of CAM for chronic illnesses and concomitant use of CAM products with other drugs. The findings could be useful for planning strategies to institute measures to ensure safe use of CAM products.