Post-transplant atrial tachyarrhythmias: Epidemiology, mechanisms, outcomes, and management across solid organs

Table 2 Key drug-drug interactions involving amiodarone and immunosuppressants

Interacting immunosuppressant	Mechanism	Clinical action
Cyclosporine	CYP3A4/P-gp inhibition may increase cyclosporine exposure and nephrotoxicity	Check trough levels after starting or stopping amiodarone; monitor creatinine, BP, K/Mg, and QTc; reduce dose if needed
Tacrolimus	CYP3A4/P-gp inhibition may increase tacrolimus exposure; additive QT prolongation is clinically relevant	Use early frequent trough monitoring, ECG/QTc and renal assessment; correct K/Mg; consider dose reduction in high-risk patients
Sirolimus/everolimus	mTOR inhibitors are CYP3A4/P-gp substrates; exposure and toxicity may increase	Coordinate with transplant pharmacy; adjust to troughs; monitor cytopenias, lipids, proteinuria, wound healing, and liver function

CYP3A4: Cytochrome P450 3A4; P-gp: P-glycoprotein; mTOR: Mammalian target of rapamycin; BP: Blood pressure; K: Potassium; Mg: Magnesium; QTc: Corrected QT interval; ECG: Electrocardiogram.