Overview
Drug-induced long QT syndrome (diLQTS) arises from medications prolonging the QT interval, increasing the risk of torsades de pointes and sudden death 1.Diagnosis
Key Diagnostic Criteria: Prolongation of QTc interval (>60 ms change from baseline or >500 ms absolute value) during treatment with high-risk QT-prolonging drugs 1.
Recommended Tests: Electrocardiogram (ECG) monitoring, particularly serial ECGs during initiation and maintenance of suspect medications 1.
Grading: Risk stratification using polygenic risk scores (PRS) may enhance identification of susceptible individuals, particularly in White populations 1.Management
First-Line Treatments: Discontinue the offending medication 1.
Adjunctive Treatments: Beta-blockers are commonly used to reduce the risk of arrhythmias 1.
Specific Drug: Mexiletine shows potential utility in mitigating ventricular repolarization abnormalities in experimental models, though clinical application requires further validation 3.Special Populations
Pregnancy: No specific data provided in the abstracts.
Pediatrics: No specific data provided in the abstracts.
Elderly: No specific data provided in the abstracts.
Comorbidities: No specific data provided in the abstracts.Key Recommendations
Utilize polygenic risk scores for enhanced risk stratification in White patients to identify those at higher risk for drug-induced long QT syndrome (Evidence: Moderate 1).
Discontinue the offending medication immediately upon suspicion of drug-induced QT prolongation (Evidence: Expert opinion).
Consider beta-blocker therapy to reduce the risk of arrhythmias in patients with drug-induced long QT syndrome (Evidence: Moderate 1).
Further research is needed to validate the clinical utility of mexiletine in treating drug-induced long QT syndrome in humans (Evidence: Weak 3).References
1 Lopez-Medina AI, Campos-Staffico AM, Chahal CAA, Jacoby JP, Volkers I, Berenfeld O et al.. Polygenic risk score for drug-induced long QT syndrome: independent validation in a real-world patient cohort. Pharmacogenetics and genomics 2025. link
2 Darpo B, Sager PT, Fernandes P, Jamieson BD, Keedy K, Zhou M et al.. Solithromycin, a novel macrolide, does not prolong cardiac repolarization: a randomized, three-way crossover study in healthy subjects. The Journal of antimicrobial chemotherapy 2017. link
3 Satoh Y, Sugiyama A, Tamura K, Hashimoto K. Effects of mexiletine on the canine cardiovascular system complicating cisapride overdose: potential utility of mexiletine for the treatment of drug-induced long QT syndrome. Japanese journal of pharmacology 2000. link