Pharmacovigilance of Over-the-Counter Products Based in Community Pharmacy: Methodological Issues from Pilot Work Conducted in Hampshire and Grampian, UK

Layton D, Sinclair H, Bond C, et al.

Objective To develop a method to monitor the safety of an OTC medicine in the community pharmacy setting and to describe the use and self-reported side effects of OTC ibuprofen. Methods Pharmacists are important points of contact for self-care, and they are able to monitor adverse events that may be associated with OTC medicines. Pharmacies in Grampian, Scotland, and Hampshire, England, were invited to participate in an observational cohort study, and 190 accepted. By inserting leaflets in purchase bags or explaining the survey verbally, pharmacists recruited 1,021 patients who had recently purchased ibuprofen. Participants provided baseline data including socioeconomic status, smoking habits, alcohol consumption, health service utilization, and prescribed medicines they were taking. Through the use of self-completed questionnaires one week, two months, and six months after the index purchase, ibuprofen exposure variables regarding dose and past and present use were collected. Participants were also asked whether they had experienced common side effects of ibuprofen. Results A total of 658 people completed the study. Common reasons for index purchases included back pain, joint pain, and headaches. The cohorts reported different figures for: use of concomitant medication (46% Hampshire and 65.5% Grampian networks, respectively); past or current problems with asthma (7.2 and 10.5%) or stomach/peptic ulcer (3.5 and 2.1%); a higher prevalence of gastrointestinal symptoms post-purchase to pre-purchase (12.9 vs 7.2%, P=0.0006 and 8.8 vs 5.8%, P=0.034); ingestion of doses in excess of the licensed nonprescription dose (5.1 and 3.9%); and discontinuation of treatment because the medicine upset their bodies (4.5 and 3.1%). Most did not seek medical advice for their symptoms. Conclusion According to the authors, greater vigilance is needed for adverse events potentially attributable to nonprescription product use. Information gathered by community pharmacy networks could be useful to determine the safety of OTC medication such as ibuprofen. More must be done to identify collection methods that maximize patient recruitment in studies and maintain acceptable follow-up rates. Pharmacoepidemiology and Drug Safety 2002;11:503-513. Return to Top