Torsade de pointes associated with moxifloxacin: a rare but potentially fatal adverse event

Area of Science:

• Cardiology
• Pharmacology

Background:

• Torsade de pointes (TdP) is a rare, life-threatening ventricular arrhythmia associated with a prolonged QT interval.
• Acquired long QT syndrome is frequently drug-induced, often due to medications prolonging ventricular repolarization.
• Fluoroquinolone antimicrobials are known to prolong the corrected QT interval, but TdP is an infrequent complication.

Observation:

• A patient with multiple TdP risk factors, including female sex, advanced age, bradycardia, and renal failure, developed TdP.
• The arrhythmia occurred on the fourth day of treatment with oral moxifloxacin (400 mg/day).

Findings:

• Discontinuation of moxifloxacin led to normalization of the corrected QT interval.
• The patient required and received a permanent cardiac pacemaker.
• No recurrence of arrhythmia was observed during an 11-month follow-up period.

Implications:

• This case underscores the potential cardiotoxicity of fluoroquinolones, particularly in susceptible individuals.
• Careful patient selection and monitoring are crucial when prescribing moxifloxacin, especially in those with risk factors for QT prolongation.
• Understanding drug-induced QT prolongation is vital for preventing fatal arrhythmias.