Survey of patients’ experiences and their certainty of suspected adverse drug reactions

Background Patients are best placed to recognize and monitor their own experiences of adverse drug reactions (ADRs), however they may need medicines information to help them do so. In Thailand patients rarely receive information leaflets, but are permitted to report ADRs directly to the regulator. Objectives To determine frequency of ADRs reported by hospital out-patients, the information sources used to evaluate suspected ADRs and patients’ confidence in ADR identification. Setting Srinagarind hospital in Khon Kaen, the second-largest province of North-eastern Thailand. Methods A questionnaire designed for self-completion and distributed to out-patients at this tertiary hospital using systematic random sampling over a 2-month period. Main outcome measures Frequency of reported ADRs, information sources confirming ADRs and degree of confidence in ADR identification. Results Of 1,195 questionnaires distributed, 1,044 usable responses were obtained (87.4 %). The majority of respondents were female (57.1 %) with average age 39.6 ± 13.6 years. Of 1,044 valid questionnaires, 257 (24.7 %) patients indicated they had experienced an ADR with high (56.0 %) and moderate (31.9 %) degree of confidence in ADR identification. The most frequent causative agent was an anti-infective (19.1 % of the patients). Major sources of information used for ADR assessment were healthcare professionals (35.5 %) and past ADR experience (25.5 %), with information leaflets being used infrequently (14.6 %). Conclusions This study showed high frequency of ADRs among Thai patients who were mostly confident about casual relationships with medicines. Patients mostly used healthcare professionals as confirmation source to evaluate suspected ADRs. Reliable medicines information sources such as information leaflets should be made more widely available.