Background Drug-drug interactions (DDIs) are one of the main causes of adverse drug reactions in polytreated elderly patients.

Purpose Under the supervision of the Pharmacological Department of the University of Bologna, 7 hospitals in the Emilia Romagna Region participated in a multicentre pharmacovigilance study to evaluate the prevalence of 53 DDIs in the study population and their modifications after appropriate educational interventions for general practitioners (GPs).

Material and methods Drug prescriptions for elderly patients (aged ≥65 years) chronically treated with 5 or more drugs were collected during the first 6 months of the years 2011, 2012 and 2013. The study was divided into three periods: data collection during the first 6 months of the years 2011 and 2012 (first period); educational interventions for GPs during the last 6 months of the year 2012 (second period); and data collection after educational interventions during the first 6 months of the year 2013 (third period).

Results Percentages of polytreated elderly patients in the first 6 months of 2011, 2012 and 2013 were, respectively, 15.2%, 15.6% and 16.7%. For each patient the mean number of DDIs was 1.5 in the entire period. The most common DDIs (prevalence more than 10%) showed the following modifications between the first and third periods: antidiabetics and beta blockers +1.5%; ACE inhibitors/Sartans and NSAIDs -1.9%; diuretics and NSAIDs -2.3%; SSRI and NSAIDs/acetylsalicylic acid -0.8%; and triple whammy interactions (ACE inhibitors, diuretics, NSAIDs) -1%.

Conclusion From our results, the educational interventions for GPs showed efficacy in limiting the mean number of DDIs for polytreated elderly patients, especially for DDIs regarding NSAIDs.

References and/or Acknowledgements

1. Lapi F, Azoulay L, Yin H, et al. Concurrent use of diuretics, angiotensin converting enzyme inhibitors, and angiotensin receptor blockers with non-steroidal anti-inflammatory drugs and risk of acute kidney injury: nested case-control study, BMJ2013;346:e8525. doi: 10.1136/bmj.e8525.:e8525:e8525

2. Laroche ML, Charmes JP, Nouaille Y, et al. Impact of hospitalisation in an acute medical geriatric unit on potentially inappropriate medication use. Drugs Aging 2006;23:49-59

3. Gagne JJ, Maio V, Rabinowitz C. Prevalence and predictors of potential drug-drug interactions in Regione Emilia-Romagna, Italy. J Clin Pharm Ther 2008;33:141-51

References and/or AcknowledgementsNo conflict of interest.