Analysis of potential drug interactions and adverse reactions to nonsteroidal anti-inflammatory drugs among the elderly

Abstract Objective: The aim of the present study was to analyze potential drug interactions and adverse reactions to NSAIDs in elderly users of a private drug distribution service. Method: A prospective, exploratory and descriptive study with a quantitative approach was performed. The elderly users of NSAIDs attended by the service were interviewed and their prescriptions analyzed between May and September, 2014. Analysis of drug interactions was performed through computerized databases. The post-sales analysis of adverse reactions was performed using the Adverse Drug Reaction Probability Scale. Statistical analysis was performed with the Chi-squared and Fisher's Exact tests. Results: The study evaluated 200 elderly persons, among whom women predominated (56.5%). The average age was 65 years ±10. The NSAIDs accounted for 38.7% of prescription drugs used, and included dipyrone (26.9%), nimesulide (22.8%) and ketoprofen (16.3%). A total of 8.5% of such drugs were considered inappropriate medications for the elderly. A total of 104 potential drug interactions were identified, of which 24% were considered highly clinically significant. The NSAIDs with the greatest risk of interactions were ketoprofen 46.2%, ketorolac 14.4%, nimesulide 12.5% and diclofenac 9.6%. In post-sales monitoring 30.5% of the elderly persons reported undesirable symptoms after the use of NSAIDs, with stomach discomfort the most prevalent (17%). Conclusion: The present study confirmed the importance of monitoring the use of NSAIDs among the elderly due to the increased risk of drug interactions and adverse reactions associated with age, concomitant diseases, multi- prescriptions and polypharmacy. The choice of appropriate drugs for the elderly, the reconciliation of all the medications taken by the patient, and effective pharmaceutical care are measures that can contribute to the rational and safe use of NSAIDs.