Pharmacological Basis of Drug-Induced QT Prolongation and Torsades de Pointes: Implications for Clinical Practice in Nigerian Hospitals

Background: Drug-induced QT prolongation and the resultant potentially fatal arrhythmia, torsades de pointes, represent a significant cardiac safety concern associated with a wide range of commonly prescribed medications. In Nigeria, limited awareness of this pharmacological risk among prescribers may contribute to unrecognised cardiac events. This study characterised the prevalence of QT-prolonging drug prescribing and associated risk factors in Nigerian hospital inpatients. Methods: A prospective observational study was conducted in the medical and surgical wards of three tertiary hospitals in Kano (North West), Enugu (South East), and Lagos (South West). Prescriptions of 480 inpatients were screened using the CredibleMeds QTDrugs database. ECG data were reviewed where available. Risk factor scoring for drug-induced QT prolongation was calculated using the Tisdale risk score. Results: At least one QT-prolonging drug was identified in 58 percent of prescriptions. Concurrent use of two or more QT-prolonging drugs was observed in 21 percent. High Tisdale risk scores were recorded in 27 percent of patients on QT-prolonging agents. Baseline ECG monitoring prior to drug initiation was performed in only 19 percent of high-risk patients. Conclusion: QT-prolonging drug prescribing is prevalent in Nigerian hospitals with inadequate ECG monitoring. Prescriber education and pharmacist-led screening tools for QT risk must be incorporated into clinical practice. Keywords: QT prolongation, torsades de pointes, drug safety, Nigerian hospitals, cardiac pharmacology