Professor Department of Pharmacy Practice, JSS College of Pharmacy, JSS Academy of Higher Education & Research, Mysore-570 015. India Mysuru, India
Background: Drug-related problems (DRPs) are a significant concern associated with the use of NTIDs, which can lead to suboptimal therapeutic outcomes or adverse drug events.
Objectives: To determine the rate and pattern of drug related problems (DRPs) associated with narrow therapeutic index drugs (NTIs).
Methods: The patients who are receiving at least one NTI and admitted to the wards of General Medicine, Cardiology and Neurology in a tertiary care teaching hospital were enrolled with consent and followed till their discharge. The list of NTIDs was prepared through literature review. The Helper and Strand’s classification of Drug Related Problems (DRPs) was adapted, and the eligible patients’ case sheets were reviewed for DRPs. Adverse Drug Reactions (ADRs) were assessed for causality using the WHO-UMC Probability scale, and severity by Hartwig’s. The data obtained were assessed categorically and represented as [n (%)].
Results: During the study period, 88 patients experienced at least one DRP. A total of 241 DRPs were identified, with an average of 2.74 DRPs per patient. Drug-drug interactions (DDIs) [147 (61%)] were the predominant DRP, followed by sub- therapeutic dose [44 (18.26%)] and adverse drug reaction (ADR) [24 (9.96%)]. Majority of the reported DDIs were “moderate” [119 (80.95%)] in nature. Of these 147 reported DDIs, majority were pharmacokinetic interactions [57 (38.10%)], wherein [32 (57.14%)] were associated with altered metabolism and, [20 (35.71%)] were altered absorption. Amongst the pharmacodynamic interactions [39 (26.53%)], [27 (69.23%)] were synergistic in nature. Hypoglycemia was reported the most contributing to 79.17% of the overall ADRs followed by nausea and vomiting (8.33%), and hyponatremia, rash and gynecomastia being [1 (4.17%)]. The causality assessment for majority of identified ADRs were classified as “probable” [17 (70.83%)] and 75% of ADRs were classified as “moderate” in severity. Insulin [19 (79.17%)] was the commonly implicated drug and [15 (62.50%)] of the ADRs were managed specifically and all cases recovered with no sequel. Acceptance rate of pharmacist intervention was found to be 97.92%.
Conclusions: NTI drugs demand low margin of error and any DRP would result in extended stay in hospital. Early identification and remedial action of the DRPs will reduce the risk of drug induced morbidity and mortality.
