Quantitative Analysis of Drug- Drug Interactions of OTC Drugs with other Prescribed Drugs Collected from Different Hospitals and Clinics of Karachi, Pakistan

In the modern era of health profession, drug prescribing practices have become more complicated as the number of drug inventions is increasing with numerous diseases which lead to a situation to prescribe a concurrent therapy of more than one therapeutic regime at a time. Under these clinical circumstances, in spite of making a patient profile and close monitoring of medication dosage, there is an increased incidence tendency of drug interaction which may counteract the mechanism of each other. The core aim of the current study is to analyze the drug-drug interactions of OTC drugs with other prescribed drugs. For this purpose, a total number of 448 prescriptions were collected from different retail pharmacies and physician clinics running under the hospitals of Karachi, Pakistan over a period of 9 months (Jan, 2009 to Sep, 2009). Software Micromedex (R) Healthcare Series, Vol.142, 1974 – 2009, Thomson Reuter, was used as a reference to determine the interactions. The total numbers of 2124 of drug-drug combinations were reviewed under the study, out of which 357 drug-drug interactions were identified in the entire study. On the basis of Micromedex software drug-drug interaction categorization, these 357 drug-drug interactions were categorized into the Severity, Onset and Documentation. Based on Severity, 13 (3.46%) interactions were found to be Major, 275 (77.03%) were Moderate and 69 (19.33%) were Minor. Based on Onset, 115 (32%) interactions were reported as Rapid and 236 (66%) were Delayed, and 6 (2%) were not specified. Based on Documentation, 11 (3%) interactions were documented as an Excellent, 224 (63%) interactions were Good and 122 (34%) interactions were Fair. Overall, the end results of the entire study found interactions of Aspirin with ACE inhibitors and Clopidogrel, Iron, Zinc and Calcium with Ciprofloxacin, while Ibuprofen with Lisinopril as a top large number of interactions. However, the current study raises the awareness of the pharmacist to make an intervention strategy on emphasizing the proper prescribing practice and to take a holistic approach toward the further enrichment of opportunities subsist for greater involvement in safe and effective utilization of therapeutic regime.