Leading 20 drug–drug interactions, polypharmacy, and analysis of the nature of risk factors due to QT interval prolonging drug use and potentially inappropriate psychotropic use in elderly psychiatry outpatients

BACKGROUND: Psychotropic medications extend corrected QT (QTc) period in the electrocardiogram (ECG). Psychiatric patients exposed to ⩾1 psychotropic medication(s) represent a group with marked probability of drug-activated QTc-prolongation. Prolonged QTc interval in elderly patients (age > 60 years) is connected to greater risk of all-cause and coronary heart disease deaths. This study aimed at investigating pattern of utilization of QTc-interval protracting medications, QT-extending drug interactions, and prevalence of QTc-interval extending hazard factors in elderly patients. METHODS: This was a cross-sectional, prospective study at the Psychiatry OPD at All India Institute of Medical Sciences (AIIMS), Rishikesh, Uttarakhand, India from 1 October 2017 to 30 August 2019 employing the pertinent prescriptions. RESULTS: A total of 832 elderly patients (age 60 years or more) visiting the Psychiatry OPD during the aforementioned study duration were investigated. About 420 (50.5%) patients were males while 412 (49.5%) were females. Of the 832 patients, 588 (70.7%) were using interacting agents with capacity to produce TdP. Almost 1152 interacting torsadogenic medication pairs were unraveled. As per AzCERT/CredibleMeds Classification, 1016 (48.8%), 724 (34.8%), and 248 (12%) agents with potential to interact were identified with ‘known’, ‘possible’, and ‘conditional risk of TdP’, respectively. The common interacting medications belonged to antidepressant (288), proton pump inhibitor (364), antipsychotic (340), antinausea (184), antimicrobial (156), and H(2) receptor antagonist (60) therapeutic categories. The all-inclusive frequency of potentially inappropriate psychotropic (PIP) agents administered was 62% (1343/2166) with Beers Criteria 2019, and 46% (997/2166) with STOPP Criteria 2015. CONCLUSION: Many geriatric patients were administered drugs and drug combinations with heightened proclivity toward QT-interval prolongation. Furthermore, reliable evidence-based online drug knowledge resources, such as AzCERT/CredibleMeds Drug Lists, Medscape Drug Interactions Checker, Epocrates Online Interaction Check, and Drugs.com Drug Interactions Checker, can facilitate clinical professionals in selecting drugs for psychiatric patients. A wise choice of medications is imperative to preclude serious adverse sequelae. Therefore, we need to exigently embrace precautionary safety means, be vigilant, and forestall QT-extension and TdP in clinical environments.