Mixing herbal products with prescription drugs can cause serious side effects, research warns

24 Jan 2018 --- Researchers have warned that the consumption of alternative herbal remedies in combination with prescription drugs can cause serious side effects, noting that patients taking warfarin and/or statins for the treatment of cardiovascular complications have reported significant interactions after taking herbal products. The products described in the study include sage, flaxseed, St. John's wort, cranberry, goji juice, green tea and chamomilla. 

An analysis of published studies and reports indicates that some herbal products may affect the properties of prescription drugs, leading to alterations in the drugs' effectiveness as well as potentially dangerous side effects. The analysis, published in the British Journal of Clinical Pharmacology, included 49 case reports and two observational studies with 15 cases of adverse drug reactions. The majority of patients were diagnosed with cardiovascular diseases, cancer and kidney transplants and were receiving mostly warfarin, alkylating agents and cyclosporine, respectively.

Although used for centuries by millions of people around the world, herbal remedies are gaining their fair share of criticism from scientists, with some saying they are an overlooked global health hazard. 

In their concluding remarks, the researchers recommend “a bench-to-bed-side approach to understand the causal relationship of HDI [herb drug interactions] linked adverse drug reactions and the potential mechanism of observed interactions. This approach will inform drug regulatory agencies and pharmaceutical companies about the need to update information in package inserts of medicines to avoid untoward adverse events, based on available data.” 

Moreover, the researchers highlight the need for the publication of causality assessment and subsequent mechanistic studies of herbs with clinically relevant HDI “to alert both clinicians and patients about the need to avoid co-usage of certain herbal medicines with specific prescribed medications.”