TOP 5 QT-PROLONGING DRUG-DRUG INTERACTIONS (QT-DDIS) IN ELDERLY PSYCHIATRY INPATIENTS RECEIVING PSYCHOTROPICS: A CROSS-SECTIONAL EVALUATION FROM NORTHEAST INDIA
Author(s)
CHAYNA SARKAR, MD(Pharmacology), DM(Clinical Pharmacology)1, ARVIND NONGPIUR, MD(Psychiatry)2, Julie B. Wahlang, MD, MBBS1, Biswadeep Das, MD3;
1North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences(NEIGRIHMS) Shillong, Pharmacology, Shillong, India, 2North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences(NEIGRIHMS) Shillong, Psychiatry, Shillong, India, 3All India Institute of Medical Sciences(AIIMS), Rishikesh, Pharmacology, Rishikesh, India
1North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences(NEIGRIHMS) Shillong, Pharmacology, Shillong, India, 2North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences(NEIGRIHMS) Shillong, Psychiatry, Shillong, India, 3All India Institute of Medical Sciences(AIIMS), Rishikesh, Pharmacology, Rishikesh, India
OBJECTIVES: Drug-induced QT interval prolongation remains a critical patient safety issue in psychopharmacology, particularly among elderly patients who are exposed to polypharmacy and comorbidities. QT-prolonging drug-drug interactions (QT-DDIs) can increase the risk of torsades de pointes (TdP), hospital readmissions, and overall treatment costs. The objectives were to identify the most frequent high-risk QT-DDIs in elderly psychiatry inpatients receiving psychotropics and to assess their potential clinical and pharmacoeconomic implications.
METHODS: A prospective cross-sectional study was conducted in the psychiatry inpatient department of NEIGRIHMS, Shillong, India. All medications which were prescribed to patients aged ≥ 60 years were reviewed for potential QT-DDIs using the AZCERT/CredibleMeds QTdrugs database (Lists 1-3, updated 7 Nov 2025) and validated via Drugs.com and Medscape Drug Interaction Checker. QT-DDIs were categorized by torsadogenic risk and potential clinical impact.
RESULTS: Among 110 elderly patients (mean age 66.8 ± 5.7 years; 58% male), a total of 218 medications were prescribed, of which 102 (47%) had QT-prolonging potential. Twenty-four unique interacting pairs with TdP risk were identified. The top five QT-DDIs were escitalopram-quetiapine (n=3), escitalopram-olanzapine (n=2), escitalopram-paroxetine (n=2), escitalopram-donepezil (n=2), and escitalopram-mirtazapine (n=2). Most involved were selective serotonin reuptake inhibitors combined with atypical antipsychotics or cognitive enhancers, posing additive cardiac risk. Avoidable QT-DDIs accounted for an estimated 12% increase in monitoring and medication adjustment costs.
CONCLUSIONS: QT-prolonging DDIs are common among elderly psychiatric inpatients and represent a preventable source of adverse cardiac events and cost escalation. Incorporation of clinical decision support systems (CDSS) such as MedSafety Scan (MSS) hosted by AZCERT’s CredibleMeds utilizing AZCERT and DDI databases can optimize prescribing, reduce iatrogenic risk, and improve cost-effectiveness in psychotropic management for the elderly. Such reliable clinical support tools, can provide comprehensive analyses of TdP risk, drug interactions, and duplicate therapies, and produce a detailed patient-specific report that allows for documentation of management plans and pharmacotherapeutic adjustments.
METHODS: A prospective cross-sectional study was conducted in the psychiatry inpatient department of NEIGRIHMS, Shillong, India. All medications which were prescribed to patients aged ≥ 60 years were reviewed for potential QT-DDIs using the AZCERT/CredibleMeds QTdrugs database (Lists 1-3, updated 7 Nov 2025) and validated via Drugs.com and Medscape Drug Interaction Checker. QT-DDIs were categorized by torsadogenic risk and potential clinical impact.
RESULTS: Among 110 elderly patients (mean age 66.8 ± 5.7 years; 58% male), a total of 218 medications were prescribed, of which 102 (47%) had QT-prolonging potential. Twenty-four unique interacting pairs with TdP risk were identified. The top five QT-DDIs were escitalopram-quetiapine (n=3), escitalopram-olanzapine (n=2), escitalopram-paroxetine (n=2), escitalopram-donepezil (n=2), and escitalopram-mirtazapine (n=2). Most involved were selective serotonin reuptake inhibitors combined with atypical antipsychotics or cognitive enhancers, posing additive cardiac risk. Avoidable QT-DDIs accounted for an estimated 12% increase in monitoring and medication adjustment costs.
CONCLUSIONS: QT-prolonging DDIs are common among elderly psychiatric inpatients and represent a preventable source of adverse cardiac events and cost escalation. Incorporation of clinical decision support systems (CDSS) such as MedSafety Scan (MSS) hosted by AZCERT’s CredibleMeds utilizing AZCERT and DDI databases can optimize prescribing, reduce iatrogenic risk, and improve cost-effectiveness in psychotropic management for the elderly. Such reliable clinical support tools, can provide comprehensive analyses of TdP risk, drug interactions, and duplicate therapies, and produce a detailed patient-specific report that allows for documentation of management plans and pharmacotherapeutic adjustments.
Conference/Value in Health Info
2026-05, ISPOR 2026, Philadelphia, PA, USA
Value in Health, Volume 29, Issue S6
Code
RWD8
Topic
Real World Data & Information Systems
Disease
No Additional Disease & Conditions/Specialized Treatment Areas, SDC: Cardiovascular Disorders (including MI, Stroke, Circulatory)