Pharmacokinetic Drug-Drug Interactions and Role of Pharmacists in Drug Therapy Management

Background: Pharmacokinetic profiles of drugs do not always follow a class effect. Therefore, all medications within a particular drug class do not have the same effect on drug substrates. This concept may be related to the management of drug-drug interactions by understanding the mechanism of interactions. Objective and Methodology: The study aims at identifying the best possible choice of drug management in drug-drug interactions. Methodology: The sensitivity of substrates as well as the strength of inhibition and induction of CYP450 coenzymes was investigated by reviewing the changes in drug clearances and area under the plasma concentrationtime curve values reported in selected studies of interactions. Results: A total of 86 potential drug-drug interactions were identified in 120 prescriptions, of which 38 (45.78%) were pharmacokinetic interactions with 79% of known interactions altering the metabolism of substrate drugs. There were 30 substrates, 22 inhibitors, and 7 inducers of the Cytochrome P450 enzyme family. Sensitive substrates, strong inhibitors as well as strong inducers present in the prescriptions were identified. Conclusion: The above approach can reduce a significant number of drug-drug interactions, and it is helpful to recommend safe treatment alternatives with the right evidence. Manjula Devi. A.S*, Mohammed Fawas, Ebin Siby, Jambulingam. P College of Pharmacy, Sri Ramakrishna Institute of Paramedical Science, 395, Sarojini Naidu Road, Sidhapudur, Coimbatore 641 044. Submission: 23 November 2019 Accepted: 29 November 2019 Published: 30 December 2019 www.ijppr. humanjournals.com Citation: Manjula Devi. A.S et al. Ijppr.Human, 2019; Vol. 17 (1): 72-84. 73 INTRODUCTION A drug interaction can be defined as the alteration of the pharmacological activity of a drug with the concomitant use of another drug or the presence of another substance. The drug whose activity is affected by such an interaction is called the object drug and the agent which precipitates such an interaction is referred to as the precipitant [1]. Drug-drug interactions represent an important and widely under-recognized source of medication errors and 23% of hospital admissions. [2]. The clinical pharmacists play an important role in health care settings, where they work in a team and use professional skills, knowledge and expertise to provide excellent patient care. Monitoring drug-related problems like potential drug-drug interactions (DDIs) is the most important one in patient care in hospital settings. Because DDIs are the leading cause of morbidity and mortality in hospitalized patients, it is important to evaluate potential DDIs in hospitalized patients. Moreover, the issue of drug interaction is a global concern. A US study found that 30.3% of patients had DDI in the ambulatory care unit [3]. In India, 66 percent of DDIs were found in the General Medicine section of a tertiary care hospital in Karnataka [4]. Another study in Chandigarh found that 8.3% of prescriptions had multiple DDIs [5]. Pharmacokinetic profiles of drugs do not always follow the class effect. Therefore, not all drugs of a particular drug class have the same effect on drug substrates [6]. This idea may be related to the management of pharmacokinetics drug-drug interactions. The study aims to analyze the prevalence and nature of pharmacokinetic DDIs seen in hospitalized patients in the Department of General Medicine and to recommend safe therapeutic alternatives for the management of drug-drug interactions by understanding the underlying mechanism. MATERIALS AND METHODS A prospective observational study was conducted in the Department of General Medicine for 10 months at 1000 bed multispecialty hospital, Coimbatore. This study protocol was approved by the Hospital Ethics Committee. Data were obtained from all inpatients in the General Medicine department with more than one prescribed medicine. Written informed consent was obtained from patients before data collection. The confidentiality of patient data was maintained throughout the study. Relevant data were obtained from patient records using customized data entry form. Prescriptions with cytochrome P450 substrates, inducers and inhibitors were recognized using the Micromedex database. We investigated the sensitivity of www.ijppr. humanjournals.com Citation: Manjula Devi. A.S et al. Ijppr.Human, 2019; Vol. 17 (1): 72-84. 74 the substrate to the inhibitor or inducer and the potential for enzyme inhibition or induction by reviewing selected research studies of drug interactions reported in peer-reviewed journals and the Micromedex Database.