Abstract

Background: Drug–drug interactions (DDIs) are very common and responsible for 6%–30%oftheadversedrugeventsthatwill increase healthcare cost and patient outcome. Polypharmacy significantly contributes to DDIs. Aims and
Objective: To assess the DDIsintheoutpatientsinthemedicinedepartmentinatertiary-carehospital.MaterialsandMethods:Theprescriptionofpatients attendingOPDofmedicinedepartmentwereanalyzedfordemographyofpatientsandpotentialdrug–druginteraction(pDDI).pDDI werecheckedbyfreelyavailabledruginteractioncheckeronInternet.pDDIwereclassifiedmajor,moderate,andminoraccordingto severity and, by its mechanism, as pharmacokinetic, pharmacodynamic, or pharmacokinetic + pharmacodynamic. Statistical analysis was done using appropriate statistical software (MS Excel, Epi info, etc.).
Results: Of the 300 patients who attended the medicine OPD during the study period, 253 patients were included in our study. From these, 128 (50.59%) were men and 125 (49.41%) women. Among these 253 patients, 147 (58.27%) patients had at least one pDDI and 106 (41.9%) patients had ± no pDDIs. The incidence of pDDI per patient was 1.68 2.68 in our study. Average number of drugs prescribed per patient was ± 4.4 1.48 in our study. A direct correlation was observed between the age of the patients and the number of pDDIs (r=0.35, Po 0.01), between the age of the patients and the number of the drugs prescribed (r=0.18, Po 0.01), and between the number of drugs prescribed and thenumber of pDDIs (r=0.69, Po 0.01). Among 423 pDDIs, 215 (50.83%) werepharmacodynamic drug interactions, 163 (38.53%) pharmacokinetic, and 45 (10.64%) showed both kinds of mechanisms. Interactions with major severity accounted for seven (1.65%) of the total pDDIs, while those with moderate and minor severity accounted for 321 (75.87%) and 95(22.46%),respectively.
Conclusions: Inourstudy,wefoundthatmostcommonpDDIswerepharmacodynamicinnatureandof moderate severity. The number of pDDI increased with increaseintheageofpatientsandthenumberofdrugsprescribed.