Summary Safety Review - Goldenseal - Potential Herb-Drug Interaction
Review decision
A Summary Safety Review complements other safety related information to help Canadians make informed decisions about their use of health products. Each summary outlines what was assessed in Health Canada’s review, what was found and what action was taken by Health Canada, if any.
Issued: 2015-04-30
Product
Goldenseal (Hydrastis canadensis)
Potential Safety Issue
Herb-Drug Interaction
Overview
Use in Canada
- In Canada, goldenseal-containing oral health products are traditionally used in herbal medicine for aiding or alleviating a variety of digestive problems such as indigestion or heartburn, infectious and inflammatory conditions of the digestive tract such as inflammation of the lining of the stomach (gastritis), or to increase appetite. Health Canada has licensed several hundred natural health products (NHPs) that have goldenseal listed as a medicinal ingredient.
Safety Review Findings
- There were no Canadian or international reports of adverse reactions assessed by Health Canada as having been associated with interactions between goldenseal-containing health products and other health products or medications. Side effects with all medications, and in particular NHPs, are known to be underreported.
- Some published studies have shown that goldenseal can slow down the activity of certain enzymes referred to as "cytochrome P450 enzymes" mainly in the liver. These enzymes are responsible for processing and eliminating many substances that are orally ingested, including medications (e.g., certain antidepressant drugs, anti-infective drugs, anti-anxiety drugs, cardiovascular drugs, cholesterol lowering drugs, etc.).
- By slowing down the rate of these processing and eliminating enzymes, certain medications could remain in the body for longer than normal, potentially reaching toxic levels. In some cases, medications are given in their inactive form and require processing by these enzymes to become activated in the body.
- Health Canada has identified that many other factors can also affect the potential for any herb-drug interaction, including genetics, age and health status as well as the type, dose, timing and composition of health products being used together.
Conclusions and actions
- The current available evidence suggests that use of oral goldenseal may contribute to herb-drug interactions, but the data is limited and no domestic or international cases of goldenseal-drug interactions are known to Health Canada.
- At this time, Health Canada will continue to monitor adverse reaction information for oral goldenseal-containing health products, as it does for all health products, to identify and assess potential harms. Health Canada will keep Canadians informed and take action, as appropriate, if any new safety information is identified.
- Health Canada will publish an article in the April 2015 issue of the Health Product InfoWatch to raise awareness and to encourage the reporting of related adverse reactions with goldenseal.
Additional information
The analysis that contributed to this safety review included scientific and medical literature, Canadian and international adverse reaction reports and what is known about the use of this drug both in Canada and internationally.
For additional information, contact the Marketed Health Products Directorate.
Footnotes
- Medsafe. Drug Metabolism - The Importance of Cytochrome P450 3A4. Prescriber Update 2014;35(1):4-6.