Minor
Suspected
Description
Tacrolimus may mildly prolong the QT interval; metoprolol's bradycardic effect may compound this modestly, though clinically significant arrhythmia is uncommon at standard doses.
Mechanism
Tacrolimus can prolong cardiac repolarisation (QTc prolongation); beta-blockers reduce heart rate, potentially exacerbating any QT-related risk at slow rates, though the effect is generally negligible with therapeutic metoprolol.
Clinical Significance
Limited evidence of clinically meaningful interaction at normal therapeutic doses; relevance increases if QTc is already prolonged from other causes.
Management
Routine monitoring is adequate; obtain baseline ECG in patients with pre-existing QTc prolongation or additional QT-prolonging agents.