Sibutramine-associated QT interval prolongation and cardiac arrest
David Ernest1, Alexander Gershenzon, Carmela E Corallo
1Box Hill Hospital, Victoria, Australia. david.ernest@easternhealth.org.au
The Annals of Pharmacotherapy
|August 30, 2008
Summary
Sibutramine, a weight-loss drug, may prolong the QT interval, increasing the risk of dangerous heart rhythms like ventricular fibrillation. Clinicians should monitor patients for ECG changes and be cautious with co-prescribing other QT-prolonging medications.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Medicine
Background:
- Sibutramine is a centrally acting appetite suppressant.
- Its mechanism involves inhibiting the reuptake of neurotransmitters like noradrenaline, dopamine, and serotonin.
- This action is shared by other drugs known to prolong the QT interval.
Observation:
- A 51-year-old woman with obesity developed ventricular fibrillation and cardiac arrest after 4 months of sibutramine therapy.
- Electrocardiogram (ECG) revealed sinus tachycardia and a significantly prolonged QTc interval (545 msec).
- The QTc interval normalized after discontinuation of sibutramine.
Findings:
- A probable association between sibutramine use and QT interval prolongation was identified.
- The Naranjo probability scale supported the likelihood of this adverse drug reaction.
- No underlying cardiac abnormalities were found in the patient.
Implications:
- Sibutramine may pose a risk for QT interval prolongation and associated cardiac events.
- Current prescribing information for sibutramine lacks specific warnings regarding QT prolongation.
- Healthcare providers should exercise caution and monitor patients for ECG abnormalities, especially when co-prescribing other QT-prolonging drugs.
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