Major
Escitalopram × tacrolimus
Selective serotonin reuptake inhibitors (SSRIs)×Calcineurin inhibitor (immunosuppressant)
Mechanism
Tacrolimus prolongs the QT interval, especially with hypomagnesaemia (typical on calcineurin inhibitors). Escitalopram also prolongs QT dose-dependently (FDA caps at 20 mg/day). Effects add up.
Symptoms
QT prolongation on ECG, dizziness, syncope, palpitations. Severe cases: polymorphic ventricular tachycardia (torsades de pointes). Risk is higher with hypokalaemia and hypomagnesaemia.
Management
Limit the combination: cap escitalopram at 10 mg/day. ECG before start and at 2 weeks; maintain potassium and magnesium. Alternative antidepressant with minimal QT effect: mirtazapine or agomelatine.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.