Overview
Drug-induced bradycardia refers to a slowing of the heart rate caused by certain medications, potentially leading to hemodynamic instability or other cardiac complications. 2Diagnosis
Monitor heart rate closely in patients on known bradycardic agents.
Electrocardiogram (ECG) may reveal prolonged QTc interval in some cases, particularly with certain drugs like ondansetron 1.
Assess for clinical signs of bradycardia such as hypotension, altered mental status, and signs of poor perfusion.Management
First-line: Discontinue or reduce the dose of the offending medication if feasible 1.
Adjunctive: Administer atropine (typically 0.5-1 mg IV, titrated) for symptomatic bradycardia 2.
Consider temporary pacing if atropine is ineffective or contraindicated.
Manage underlying causes and stabilize hemodynamics with fluid or vasopressors as needed.Special Populations
Pediatrics: Monitor QTc interval closely in children receiving ondansetron, as low-dose exposure can lead to statistically significant but clinically mild QTc prolongation without observed dysrhythmias 1.
Elderly: Increased susceptibility to drug-induced bradycardia; careful medication review and dose adjustment are crucial.
Comorbidities: Patients with pre-existing cardiac conditions may require more vigilant monitoring and intervention 12.Key Recommendations
Evaluate and monitor QTc interval in pediatric patients receiving ondansetron to prevent significant QTc prolongation 1 (Evidence: Moderate).
Use atropine for symptomatic bradycardia induced by drugs, with careful titration based on response 2 (Evidence: Weak).
Regularly review and adjust medications in elderly patients to minimize the risk of drug-induced bradycardia 1 (Evidence: Expert opinion).References
1 Carneiro IMC, Castelo Branco PES, Franco AHS, Oliveira AP, Aguiar AMA. Effect of ondansetron on QTc interval prolongation in healthy pediatric patients: a systematic review and meta-analysis. Revista paulista de pediatria : orgao oficial da Sociedade de Pediatria de Sao Paulo 2026. link
2 Whishaw IQ, Schallert T. Hippocampal RSA (theta), apnea, bradycardia and effects of atropine during underwater swimming in the rat. Electroencephalography and clinical neurophysiology 1977. link90175-4)