Screening of herbal-drug interactions during dispensing: A simulated patient study in community pharmacies

Abstract

Background: Community pharmacists play a pivotal role in ensuring safe and effective self-medication. In Hungary, national guidelines require structured questioning and risk assessment during consultative dispensing, however Real-world adherence is uncertain. Herbal products such as St. John’s wort, which has well-documented interactions with antidepressants and hormonal contraceptives, represent a high-risk area where inadequate counselling may have serious clinical consequences. Objective: This study aimed to assess the quality of consultative dispensing in Hungarian community pharmacies, with a particular focus on the identification and management of clinically relevant drug–herb interactions. Methods: A simulated patient study was conducted between January and April 2024 in pharmacies across Csongrád-Csanád County, Hungary. A standardized scenario involved a young woman requesting St. John’s wort while taking escitalopram and an oral contraceptive. After each visit, a structured questionnaire recorded the information elicited by pharmacy staff (pharmacist, technician, or pharmacy student, based on name tags), recognition of clinically relevant interactions, and whether dispensing, counselling, or referral occurred. Descriptive statistics were used to evaluate adherence to guideline-based counselling. Outcomes were classified as: (1) dispensed without warning/referral; (2) dispensed with warning and/or referral; (3) not dispensed with correct justification (interaction(s) recognised and communicated); (4) not dispensed with incorrect or unclear justification. Results: A total of 110 pharmacies (81.5% of all pharmacies in the county) were visited. In 89 cases, staff initially intended to dispense St. John’s wort without further questioning. After disclosure of escitalopram and oral contraceptive use, dispensing was correctly refused in 62 cases (56.4%); however, only 52 refusals (47.3%) were supported by appropriate clinical reasoning. Correct performance was observed in 41.0% of pharmacist-led and 28.6% of technician-led encounters. Interactions with escitalopram and oral contraceptives were identified in 35.2% and 27.4% of cases, respectively, and physician referral occurred in 43.6%. Lack of structured questioning frequently resulted in missed safety risks. Conclusion: This study reveals substantial gaps between guideline recommendations and real-world pharmacy practice. Inadequate questioning of patients and failure to recognize clinically significant interactions highlight the need for better implementation of guidelines to improve patient safety when dispensing OTC and herbal medicines.