An evaluation of pharmacist and health food store retailer's knowledge regarding potential drug interactions associated with St. John's wort.

BACKGROUND: Natural health products (NHP) are increasingly being used by patients concomitantly receiving prescription drugs, which can result in potentially serious drug-herb interactions. This is particularly true for St. John's wort. OBJECTIVE: This study was conducted to evaluate pharmacists and natural health product retailers' knowledge on this topic. METHODS: An interviewer approached 24 pharmacists and 6 natural health product retailers to obtain information regarding St. John's wort. If asked, the interviewer indicated that they were currently using cyclosporine to treat a problem of proteinuria. The response of the pharmacist or NHP retailer to a series of questions was recorded after the encounter. RESULTS: 90% of respondents indicated that St. John's wort was useful for treating depression. Two-thirds of the respondents required prompting by the interviewer before providing any comments pertaining to safety. 60% of the respondents inquired about concurrent medications and 40% made statements regarding potential drug-herb interactions. CONCLUSION: Despite the potential for a serious drug-herb interaction involving St. John's wort and cyclosporine, less than half of the pharmacists and natural health product retailers that were encountered in the study addressed this topic with the prospective patient/client. Individuals selling natural health products need to communicate more information to their patients/clients regarding potential drug-herb interactions.

Warfarin use in atrial fibrillation: A random sample survey of family physician beliefs and preferences.

BACKGROUND: In clinical practice, warfarin is underused for the prevention of stroke in individuals with atrial fibrillation despite unequivocal evidence of benefit and acceptable safety. OBJECTIVE: To ascertain, from primary care physicians, their beliefs and preferences regarding the use of warfarin in patients with atrial fibrillation. MATERIALS AND METHODS: A questionnaire was mailed to a random sample of 1000 primary care physicians in Ontario. Physician prescribing preferences from among treatment options available (warfarin, acetylsalicylic acid, ticlopidine, no therapy and other) were recorded for four separate scenarios of atrial fibrillation with varying degrees of risk for stroke. Physician perception of the risks associated with warfarin use and their awareness of the evidence of benefit were assessed. RESULTS: Three hundred twenty-four physicians returned completed questionnaires. Among the four scenarios, physicians choosing not to use warfarin were three to six times more likely than physicians choosing to use warfarin to believe that there was inadequate evidence of benefit of warfarin for stroke prophylaxis, and they were four to six times more likely to be concerned about the risks of hemorrhage. These beliefs did not change significantly with scenarios describing patients with a high risk of stroke. CONCLUSIONS: Physician reluctance to use warfarin is associated with a false understanding of the benefit to risk ratio, which arises from a low appreciation of therapeutic benefits and a high concern regarding hemorrhage.