RESUMO
OBJECTIVES: To evaluate health care professionals' knowledge on warfarin interactions with drugs and herbs. METHODS: A self-administered questionnaire was developed to assess health care professionals' knowledge on warfarin interactions with drug and herb. Respondents were asked to classify 15 drugs that may effect on warfarin action as "enhance", "inhibit ", "no effect". The study sample involved health care professionals (physicians, pharmacists and nurses) from king Salman hospital, Saudi Arabia. RESULTS: About 92.2% of health care professionals identified warfarin interactions with aspirin, 4.4% for warfarin and fluoxetine. Warfarin and cardiac agents (atenolol) was correctly identified by 11.1% of respondents. In warfarin -herb interactions section, the majority of respondents (66.7%) identified the interaction between green tea and warfarin. Approximately one-third of respondents (n=33) correctly classified warfarin interactions with cardamom. No significant difference was found between the health care professionals (p=0.49) for warfarin-drug interactions knowledge score and p= 0.52 for warfarin- herb interactions knowledge score. CONCLUSION: This study suggests that health care professionals' knowledge of warfarin- drug-herb interactions was inadequate. Therefore, health care professionals should receive more education programs about drug-drug/herb interactions to provide appropriate patient counseling and optimal therapeutic outcomes.