Herbal supplements may cause dangerous drug interactions in orthopedic surgery patients

Although complementary and alternative medical treatments are growing in popularity, a review article published in the Journal of the American Academy of Orthopaedic Surgeons notes a number of these products, such as herbal supplements, may have serious, potentially harmful side effects when combined with medications prescribed during and after surgery.

According to the review, around 20% of prescription users also take an herbal supplement — with rates increasing as high as 35% to 70% among orthopedic patients who are candidates for surgery.

“Herbal remedies are classified as dietary supplements, meaning they are exempt from the safety and efficacy regulations that the U.S. Food and Drug Administration requires for prescription and over-the-counter medications,” review author David T. Rispler, MD, stated in an American Academy of Orthopaedic Surgeons press release. “As a result, individual herbal remedies have not been thoroughly evaluated in large clinical trials, and little information is available on the interactions between drugs and herbs.”

Noteworthy interactions

The review noted that many of the most popular herbal supplements in use today can result in serious side effects when used in conjunction with prescription medications. Feverfew, ginger, cranberry, St. John’s Wort and ginseng, for example, reportedly interact with warfarin. Other examples cited in the release include:

Feverfew, ginger and gingko, which can interact with aspirin;
Valerian, which can intensify anesthetics;
St. John’s Wort, which can reportedly interact with immunosuppressive drugs and potentially lead to transplant rejection;
Glucosamine, chondroitin and flavocoxid, which can affect clotting agents;
Black cohosh, which can interact with tamoxifen; and
Cat’s claw, which can interact with clotting agents.

The review also cautioned that many herbal products can pose additional danger due to being marketed as “natural” or “homeopathic,” resulting in patients assuming there is no danger of interaction.

Communication is key

Rispler noted physicians rarely ask patients about alternative medical products during intake interviews — and thus these patients may continue using the products because they perceive no risks.

According to the release, most surgery-related side effects can be avoided by ceasing use of the CAM product at least 1 week to 2 weeks preoperatively and during the postoperative period while prescription medications are being administered. The problem, Rispler stated, arises when physicians do not know a patient is using a CAM product — thus, communication with the patient about the use of CAM products should be taken into account.

Reference:

Rispler DT, Sara J. The impact of complementary and alternative treatment modalities on the care of orthopaedic patients. J Am Acad Orthop Surg. 2011;19(10):634-643.

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I commend the authors for writing this interesting review. The use of complementary and alternative medical (CAM) therapies, either available over the counter or via the internet, is a growing industry. As highlighted, many doctors have not routinely included CAM therapies in the drug history. The belief that CAM therapies "do no harm" has been challenged by serious drug interactions. The authors suggest CAM therapies are not subjected to the same level of clinical evaluation as pharmaceuticals.

It is important to respect patient choice. As clinicians we should present an unbiased opinion regarding their choice of alternative therapy, of which many patients feel strongly. This paper adds to the evidence base which may be included in the discussion or decision making process. Clearly, it is important to remember some CAM therapies may offer genuine benefits. The recommendation that CAM therapies should be stopped before and after surgery is sensible.

— Graeme S. Carlile, MBChB, MRCS
Trauma & Orthopaedics Department
Plymouth Hospitals NHS Trust
Devon, UK

Disclosure: Carlile has no relevant financial disclosures.