A study of potential adverse drug-drug interactions among prescribed drugs in medicine outpatient department of a tertiary care teaching hospital.

Objective: To evaluate prevalence, types, and severity of potential adverse drug-drug interaction in medicine out-patient department.

Materials and methods: A single-point, prospective, and observational study was carried out in medicine OPD. Study began after obtaining approval Institutional Ethics Committee. Data were collected and potential drug-drug interactions (pDDIs) were identified using medscape drug interaction checker and were analyzed.

Result: A total of 350 prescriptions with mean age 52.45 ± 14.49 years were collected over a period of 5 months. A total of 2066 pDDIs were recorded with mean of 5.90 ± 6.0. The prevalence of pDDI was 83.42%. Aspirin was most frequently prescribed drug in 185 (10.15%) out of total of 1821 drugs It was also the most frequent drug implicated in pDDI i.e. in 48.16%. The most common pDDI identified was metoprolol with aspirin in 126 (6.09%). Mechanism of interactions was pharmacokinetic in 553 (26.76%), pharmacodynamic in 1424 (68.92%) and 89 (4.30%) having an unknown mechanism. Out of all interactions, 76 (3.67%) were serious, 1516 (73.37%) significant, and 474 (22.94%) were minor interaction. Age of the patients (r = 0.327, P = 0.0001) and number of drugs prescribed (r = 0.714, P = 0.0001) are significantly correlated with drug interactions.

Conclusion: Aspirin being the most common drug interacting. The use of electronic decision support tools, continuing education and vigilance on the part of prescribers toward drug selection may decrease the problem of pDDIs.