Major
citalopram × tacrolimus
SSRI (selective serotonin reuptake inhibitor)×Calcineurin inhibitor (immunosuppressant)
Mechanism
Tacrolimus prolongs the QT interval, especially with hypomagnesaemia (common on calcineurin inhibitors). Citalopram also prolongs QT dose-dependently (FDA caps at 40 mg/day). Effects add up.
Symptoms
QT prolongation on ECG, dizziness, syncope, palpitations. Severe cases: polymorphic ventricular tachycardia (torsades de pointes). Risk rises with hypokalaemia and hypomagnesaemia.
Management
Avoid the combination. Alternative antidepressants with minimal QT effect post-transplant: mirtazapine, agomelatine, sertraline (up to 100 mg/day). ECG before start and at 2 weeks; maintain potassium and magnesium.
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.