Potential adverse reactions to herbal medicines in patients attending a nephrology clinic in Abu Dhabi, United Arab Emirates.

OBJECTIVE To provide data on herbal medicine (HM) use and safety in patients attending a nephrology clinic at Sheikh Khalifa Medical City (SKMC), Abu Dhabi, United Arab Emirates (UAE). METHODS A prospective, 3-month study between June and September 2007, investigated all patients presenting to the Nephrology Clinic of the Sheikh Khalifa Medical center (SKMC) in Abu Dhabi, UAE. A structured questionnaire determined previous and current HM use, and descriptions of associated adverse reactions. Corroborating evidence was sought from the patient's medical records. Causality was assessed by consensus from an expert panel using the Naranjo algorithm. RESULTS The HM use was widespread (468 of 688; 68%). Over two-thirds (69%) reported currently taking 3 or more herbal preparations. Patients reported using over 100 different HMs, many of them compounded mixtures; 35% could not identify a single ingredient of these mixtures, and 70% had not informed the clinic doctors that they were taking HMs. Just 2 patients had HM use recorded in their medical record. Twenty-eight HM-related adverse reactions were identified in 26 (5.6%) patients; 12 probably and 16 possibly related to HMs. Seven involved HMs alone and 21, a HM/prescription medication (PM) interaction. CONCLUSION The use of HMs in patients with underlying kidney problems was extensive and contributed additional pathology to the underlying renal disease, either alone or in combination with PMs. The reluctance of patients to inform their healthcare providers of concurrent use highlights a need to take a thorough drug history on clinic registration.