Nephrotoxicity of Natural Products.

BACKGROUND: The manufacture and sale of natural products constitute a multi-billion dollar industry. Nearly a third of the American population admit to using some form of complementary or alternative medicine, with many using them in addition to prescription medications. Most patients fail to inform their healthcare providers of their natural product use and physicians rarely inquire. Annually, thousands of natural product-induced adverse events are reported to Poison Control Centers nationwide. Natural product manufacturers are not responsible for proving safety and efficacy, as the FDA does not regulate them. However, concerns exist surrounding the safety of natural products. SUMMARY: This review provides details on natural products that have been associated with renal dysfunction. We have focused on products that have been associated with direct renal injury, immune-mediated nephrotoxicity, nephrolithiasis, rhabdomyolysis with acute renal injury, hepatorenal syndrome, and common adulterants or contaminants that are associated with renal dysfunction. KEY MESSAGES: The potential for natural products to cause renal dysfunction is justifiable. It is imperative that natural product use be monitored closely in all patients. Healthcare practitioners must play an active role in identifying patients using natural products and provide appropriate patient education.

A review of dietary supplement-induced renal dysfunction.

Complementary and alternative medicine (CAM) is a multibillion-dollar industry. Almost half of the American population uses some form of CAM, with many using them in addition to prescription medications. Most patients fail to inform their health care providers of their CAM use, and physicians rarely inquire. Annually, thousands of dietary supplement-induced adverse events are reported to Poison Control Centers nationwide. CAM manufacturers are not responsible for proving safety and efficacy, because the Food and Drug Administration does not regulate them. However, concern exists surrounding the safety of CAM. A literature search using MEDLINE and EMBASE was undertaken to explore the impact of CAM on renal function. English-language studies and case reports were selected for inclusion but were limited to those that consisted of human subjects, both adult and pediatric. This review provides details on dietary supplements that have been associated with renal dysfunction and focuses on 17 dietary supplements that have been associated with direct renal injury, CAM-induced immune-mediated nephrotoxicity, nephrolithiasis, rhabdomyolysis with acute renal injury, and hepatorenal syndrome. It is concluded that it is imperative that use of dietary supplements be monitored closely in all patients. Health care practitioners must take an active role in identifying patients who are using CAM and provide appropriate patient education.

Bitter melon (Momordica charantia): a review of efficacy and safety.

The pharmacology, clinical efficacy, adverse effects, drug interactions, and place in therapy of bitter melon are described. Bitter melon (Momordica charantia) is an alternative therapy that has primarily been used for lowering blood glucose levels in patients with diabetes mellitus. Components of bitter melon extract appear to have structural similarities to animal insulin. Antiviral and antineoplastic activities have also been reported in vitro. Four clinical trials found bitter melon juice, fruit, and dried powder to have a moderate hypoglycemic effect. These studies were small and were not randomized or double-blind, however. Reported adverse effects of bitter melon include hypoglycemic coma and convulsions in children, reduced fertility in mice, a favism-like syndrome, increases in gamma-glutamyltransferase and alkaline phosphatase levels in animals, and headaches. Bitter melon may have additive effects when taken with other glucose-lowering agents. Adequately powered, randomized, placebo-controlled trials are needed to properly assess safety and efficacy before bitter melon can be routinely recommended. Bitter melon may have hypoglycemic effects, but data are not sufficient to recommend its use in the absence of careful supervision and monitoring.