Kidney patients often use high-risk drugs and herbs

NEW YORK (Reuters Health) - People with failing kidneys may frequently use "natural" or homeopathic products and over-the-counter medications that could worsen their kidney function, a new study shows. And these products are sometimes recommended by their physician or pharmacist.

A study of 87 patients with chronic kidney insufficiency found 65 instances of drug-related problems, Dr. Lyne Lalonde of the Center de Sante et de Services Sociaux de Laval, Quebec and colleagues report.

"These results suggest that routine documentation and monitoring of over-the-counter medications and natural products by community pharmacists is warranted," the researchers write in the American Journal of Kidney Diseases.

Over-the-counter drugs, herbal medicines and other natural products can be particularly risky in patients with poorly functioning kidneys, known medically as "chronic renal insufficiency," the researchers note. These medications may directly cause kidney damage or may interact harmfully with other drugs the patient is taking.

To investigate over-the-counter medicine and natural product use among kidney patients, the researchers interviewed 46 patients with moderate renal insufficiency and 41 with severe renal insufficiency.

Overall, the patients were taking 66 different over-the-counter drugs and 25 different natural products, usually for pain relief or to treat coughs and colds. Forty-nine percent of the over-the-counter drugs had been recommended by a doctor or pharmacist, as had 19 percent of the natural products.

Eight patients reported using at least one over-the-counter drug that should not have been used, the researchers found, while 27 were using an over-the-counter drug that should have been used with caution.

Three patients were using herbal medicines that should not have been used, while seven were using herbal medicines that should have been used with caution.

And 13 percent of the potentially dangerous over-the-counter drugs were recommended by a doctor or pharmacist, as were 6 percent of the potentially dangerous natural products.

The researchers identified 65 drug-related problems. Forty-two involved at least one product, most commonly calcium or magnesium; 23 involved one or more natural products, including glucosamine, which can affect blood sugar measurements; garlic supplements, which can interact with blood-thinning drugs; and echinacea, which can directly affect kidney function.

Patients with chronic renal insufficiency are generally cared for by several specialist physicians, and about one quarter do not have a family doctor who could help to coordinate care and monitor medication use, Lalonde and colleagues point out.

However, they add, most get all their medications from a single pharmacy, "In such circumstances," the researchers conclude, "the role of the community pharmacist is crucial for the detection and management of drug related problems."

SOURCE: American Journal of Kidney Diseases, February 2007.