Can Herbal Supplements Change the Effectiveness of Pain Medications?


Occasionally, a person may find that their long-term medication has suddenly stopped working. This may occur for several reasons, such as building up a tolerance, drug interactions, not taking the medicine as directed, etc. One factor that can impact the efficacy of pain medications is taking certain herbal supplements.

Herbal supplements and medications

Herbal supplements are derived from plants; however, being from nature does not automatically make them safe. Supplements can have the ability to increase or decrease the effectiveness of certain medications, both prescription and over-the-counter. For instance, willow bark may reduce the effectiveness of diuretics and beta blockers, and enhance the effectiveness of anticoagulants. It may also raise the levels of methotrexate and phenytoin to toxic levels if taken together.

Other side effects may also occur as a result of taking specific supplements alongside pain medications. Some herbal supplements have shown to increase the risk of bleeding, liver toxicity, kidney toxicity, and central nervous system (CNS) depression when taken with certain analgesic drugs.


Taking or thinking of taking herbal supplements should be discussed with a health care professional or pharmacist to reduce the risk of medication interactions. Be alert for side effects or changes that occur while taking a supplement. Researching potential interactions is beneficial.

Regulation of herbal supplements in the U.S. and Canada

In the United States, herbal supplements and medications are not regulated with the same standards by the FDA. Therefore, it is critical to research reputable companies. Warning signs that a company may not be trustworthy include, but are not limited to, the following:

  • No toll-free number is provided.
  • Brick-and-mortar address is not furnished.
  • Company does not undertake their own research.
  • A label is unclear and with no information about the formula, ingredients, directions, or potential side effects.
  • Outlandish claims, such as a “cure-all,” are made.

In Canada, herbal supplements and herbal remedies must be approved as a natural health product and licensed by Health Canada.

Additional sources: Better Health Channel, UC Davis Health and St. Luke’s Hospital

Did you find this helpful?
You may also like