Impact of food and herbal medication on calcineurin inhibitor dose in renal transplant patients: a cross-sectional study.

The incidence and severity of interactions of herbal products with calcineurin inhibitor (CNI) metabolism in renal transplant recipients have not been systematically investigated. These patients have a high rate of herbal product consumption, including products interfering with CNI metabolism. The study aimed at identifying an impact of herbs and foods on CNI metabolism in a cohort of renal transplant recipients by conducting dietary interviews (1) in patients with very low and high CNI maintenance dose requirements and (2) by retrospective analysis of unexplained marked deviations from CNI baseline trough levels. Of 73 renal transplant recipients, 59 were treated with a CNI-based immunosuppressive regimen. Seven patients with an exceptionally high or low CNI dose were interviewed. Five of these seven patients had not consumed any plant product with known influence on CNI metabolism. In one patient chicory-coffee and bitter chocolate had been suspected as contributing to high CNI dose requirement, but the dose could not be lowered after discontinuation of these foods. Participating nephrologists reported three as yet unexplained temporary deviations from baseline CNI trough levels, of which two could be linked to newly started consumption of high volumes of herbal teas and the other to St. John's wort. Consumption of herbal products within the study cohort had no detectable impact on maintenance doses of CNI. However, herbal products, and specifically teas when consumed by the liter, could be linked to temporary strong deviations from CNI trough levels. The study demonstrates that as yet unnoticed herbal interactions with CNI can be detected by detailed dietary analysis, but that the overall impact on maintenance doses of CNI appears to be low.

Complementary and alternative medications consumed by renal patients in southern Germany.

BACKGROUND: Complementary and alternative medicine (CAM) is frequently used in the general population, yet scant data are available regarding the prevalence of these medications in patients with end-stage renal disease (ESRD). OBJECTIVE: To survey patients with ESRD regarding their use of CAM and health foods. METHODS: Consecutive patients treated with dialysis or renal transplantation for ESRD were approached by nephrologists of 5 renal centers to report their usage of and knowledge on CAM and health foods by answering a questionnaire. Of 180 approached patients, 164 returned completed questionnaires for analysis. RESULTS: Fifty-seven percent of dialysis patients and 49% of transplant patients reported to be regular CAM-consumers. CAM consumption was positively associated with female sex and negatively with diabetes as comorbidity. Forty-one different CAM products had been named, with mineral supplements and vitamins ranking first. Besides CAM, many renal patients had regularly consumed herbal teas and citrus-juices (50% and 35%, respectively). Close to 40% of the documented CAM/health food consumptions have potential risks for patients because of constituents that either accumulate in renal failure or interact with pharmaceutical medication. However, only about 50% of dialysis patients, but 73% of transplant patients used to inform their physicians about CAM consumption (P = .005). Awareness about interaction risks linked to CAM was especially low in dialysis patients when compared to transplant patients (39% versus 78%, P < .0001) and increased when physicians had routinely questioned patients about their CAM consumption. Currently, however, patients reported that only a minority of physicians had taken an active interest into consumption of these substances. CONCLUSION: Consumption of CAM and health food is common among renal patients. Physicians are currently not adequately informed about CAM consumption by their patients. Because many products are at risk to either accumulate or cause interactions with medication, physicians should take an active role to inform themselves.