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E-Case A 62-year-old man asks whether using botanical agents will help his medical problems. He is receiving anticoagulation therapy after a valve replacement and has a history of CAD and BPH. His medications include warfarin, metoprolol, and benazepril. On physical exam, BP is 184/98 mm Hg. Funduscopic exam shows A-V nicking. There is a faint bruit over the left carotid artery but no evidence of heart failure. The lungs are clear. There are several bruises over the arms and legs. The prostate gland is moderately enlarged. Which of the following botanical agents is most likely to interfere with his current medical therapy?
Studies show that 1/3 of Americans are taking some form of herbal supplement; and 70% aren't telling their doctor! The answer is A) Ginkgo biloba. Ginkgo, ginseng, garlic, and vitamin E are herbal supplements that have been associated with increased bleeding. St. John's Wort may also decrease the metabolism of coumadin and thus increase bleeding risk. These agents should be avoided in patients such as this one, who has evidence of overanticoagulation and is at increased risk of hemorrhage. Saw palmetto has been touted as a safe therapy for BPH, though adverse outcomes data are lacking. Horse chestnut seed extract has been used to improve venous insufficency. Although it contains natural coumarins, there is no evidence for a clinical antioagulant effect. Valerian has sedating properties and shouldn't be taken with alcohol, other sedatives, or prior to surgery. Hawthorn is approved in Germany for class I and II heart failure, and appears to be a mildly positive inotropic agent, but there is no data to show that hawthorn is beneficial beyond current conventional therapy. Other herbal supplements to watch out for include: Ma Huang: found in decongestants, weight loss formulas, stimulants. Lethal cardiotoxicity. Chaparral, Kava: hepatotoxicity St. John's Wort: potentially decreases effect of OCPs, CCBs, SSRIs, cyclosporine, protease inhibitors, warfarin, digoxin, chemotherapy DHEA, grapefruit juice: potentially increases toxicity of TCAs, CCBs, cyclosporine, warfarin, digoxin Consider these herbal supplements when interpreting abnormal lab tests: Vitamin C: false high creatinine Soy: inhibit thyroid production, elevate TSH; kelp, bladderwrack can increased thyroid levels; tyrosine can decrease TSH. Riboflavin (vitamin B2), cascara, senna, noni juice: false readings on urine dipstick
References I've made a handout that summarizes many common herbs and their side effects; highlights include herbs to watch out for on pre-operative assessments, and a table summarizing several of the most common herbs, the strength of the data supporting their "uses," and comments about their common toxicities. It should be included with this E-case. Ang-Lee MK, Moss J, Yuan C-S: "Herbal Medicines and Perioperative Care." JAMA 2001 Jul 11; 286(2):208-16. Ernst, Edzard. "Harmless Herbs? A Review of the Recent Literature." American Journal of Medicine Feb 1998; 104(2): 170-177. Cohen, MH, Eisenberg, DM. "Potential Physician Malpractice Liability Associated with Complementary and Integrative Medical Therapies." Ann Int Med 2002 Apr 16; 136(8): 596-603. Cupp, MJ. "Herbal Remedies: Adverse Effects and Drug Interactions." Am Fam Physician 1999 Mar 1; 59(5): 1239-45. Ernst E, Pittler MH. "Herbal Medicine." Medical Clinics of North America Jan 2002; 86(1). Lewis JD, Strom BL. "Balancing Safety of Dietary Supplements with the Free Market." Ann Int Med 2002 Apr 16; 136(8): 616-8. MKSAP 12. Napier, Kristine. "Too many vitamins?" Harvard Health Letter Jan 1996; 21(3): 1-3. Prescriber's Letter. UpToDate: Overview of Herbal Medicine, Hepatoxicity due to herbal medicine |
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