Patients' knowledge of adverse reactions to current medications.

Aims: Adverse drug reactions (ADRs) account for 3.2-7% of acute hospital admissions. The aim of this study was to assess prospectively knowledge of ADRs in patients admitted through the emergency department of a teaching hospital.

Methods: Three hundred and ninety-nine patients were admitted on acute medical call during study periods in September 2002 and May 2003. One hundred gave their perception of the risk of ADRs using visual analogue scales, where 0 indicates minimum and 10 maximum risk. The medications studied were warfarin, proton pump inhibitors (PPIs), corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs) and aspirin. Responses are compared against a medical control group.

Results: Corticosteroids were ranked most dangerous by patients (median score, 25th-75th centiles: 5.4, 2.9-8.7). Medical staff ranked NSAIDs as highest risk (6.2, 4.0-7.5). Patients identified NSAIDs as low risk (2.1, 0.7-4.9), perceiving the risk of cardiac arrhythmias and disturbance in liver biochemistry to be equivalent to risk of upper gastrointestinal ulceration and bleeding. Risk of haemorrhage was ranked as the most common ADR for warfarin by patients (8.6, 3.3-9.5) and medical staff (8.8, 7.6-9.3).

Conclusions: Patients underrate the risk of ADRs of their medications. While there is a good level of knowledge of ADRs amongst warfarin and aspirin users, there is a clear lack of knowledge regarding the risk of upper GI bleeding in NSAID users. Increased education may reduce the incidence of ADRs but it is more likely that it will serve to meet increasing patient expectations.