Pharmacovigilance of over-the-counter products based in community pharmacy: methodological issues from pilot work conducted in Hampshire and Grampian, UK

• Published in: Pharmacoepidemiology and drug safety 2002-09, Vol.11 (6), p.503-513
• Main Authors: Layton, D., Sinclair, H. K., Bond, C. M., Hannaford, P. C., Shakir, S. A. W.
• Format: Article
• Language: English
• Subjects: Adult; Age Factors; Cohort Studies; Drug Interactions; Drug Utilization Review - methods; England; Female; Humans; ibuprofen; Ibuprofen - adverse effects; Ibuprofen - therapeutic use; Incidence; Male; Middle Aged; non-prescription medicines; Nonprescription Drugs - adverse effects; Pharmacies - statistics & numerical data; pharmacists; pharmacovigilance; Pilot Projects; Product Surveillance, Postmarketing - methods; Smoking; Surveys and Questionnaires
• ISSN: 1053-8569; 1099-1557
• DOI: 10.1002/pds.734

Purpose The incidence of serious adverse events from non‐prescription medicines remains to be established. The aim of this initial pilot work, using an observational cohort design, was to determine the feasibility of conducting a pharmacovigilance study of a non‐prescription medicine, based in community pharmacies. Method Community pharmacists from Grampian, Scotland, and Hampshire, England, recruited user‐purchasers of ibuprofen. Exposure data were collected from a series of self‐completed questionnaires. Outcome data were any new symptoms, use of concomitant medication and subsequent health‐care utilization. Results A total of 1021 eligible customers were recruited, 6.4% (466/7320) and 48.2% (555/1152) by the Hampshire and Grampian networks respectively. The cohorts differed with regard to age, smoking and socio‐economic status, reason for purchase and recommendation, and duration of use. The two cohorts reported different use of concomitant medication (46.0 and 65.5%), asthma (7.2 and 10.5%), stomach/peptic ulcer (3.5 and 2.1%), a higher prevalence of gastrointestinal symptoms post‐compared 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 non‐prescription dose by 5.1 and 3.9%, and discontinuation of treatment because the medicine upset them by 4.5 and 3.1%, respectively. Most participants did not seek medical advice for their symptoms. Conclusion Greater vigilance is required for adverse events that may be attributable to non‐prescription product use. Development of pharmacovigilance models using community pharmacies is one means of systematically collecting information regarding drug safety. Further work is needed to identify a method which maximizes patient recruitment whilst maintaining acceptable follow‐up rates. Copyright © 2002 John Wiley & Sons, Ltd.