Patient self-reporting of potential adverse drug reactions to non-steroidal anti-inflammatory drugs in Thailand

Abstract

To validate and pilot in Thailand a questionnaire to enable patients to identify and report symptoms perceived as potential ADRs from NSAIDs. To determine the questionnaire's usefulness in enabling Thai out-patients to report potential ADRs. To determine the frequency with which symptoms patients reported were recorded by health professionals and the frequency of ADRs to these drugs reported to the APRM Centre. To assess whether patients reported symptoms from non COX-selective inhibitors and COX-2 selective NSAIDs with different frequencies. Out-patient departments (OPD) of a University teaching hospital in North-East Thailand. A questionnaire which incorporated an extensive symptoms checklist, developed and validated in English, was translated, piloted and validated in Thai. This was distributed to patients receiving one of five NSAIDs. Causality assessment of the symptoms reported was undertaken by a pharmacist, using data on concomitant medicines and disease states from OPD records. Frequency and type of symptoms reported by patients, recording of these in OPD records, reports sent to APRM Centre. Piloting found that patients were able to understand the questionnaire, but were unaware of drug names. A response rate of 42% was obtained: 694 usable questionnaires were returned out of 1,654 distributed. Overall 73% of respondents reported at least one symptom perceived to be an ADR. Sixty percent of symptoms reported were classed as probably or possibly an ADR. Fewer symptoms per patient were reported by those taking COX-2 selective inhibitors (3.5) than those taking non-selective NSAIDs (5.5), although there were no differences in the frequency of GI symptoms reported between these two sub-classes, which may relate to other factors, such as age, previous GI problems and prescription of protective ulcer-healing therapy. Only 5% of symptoms were recorded in OPD records and reporting of ADRs to these drugs to the APRM Centre of the Thai FDA during the study was very limited. Thai out-patients were willing and able to complete questionnaires regarding potential ADRs. The questionnaire could form part of routine out-patient monitoring, aiding identification of ADRs, and may help to increase ADR reporting in Thailand.