MAJOR — Use With Caution
🔴 AVOID — Additive QT prolongation risk. FDA 2011 safety communication limits citalopram dosing due to QT effects. Combined with ondansetron QT prolongation, cardiac arrhythmia risk increases.
Evidence level: STRONG
Both Celexa (citalopram) and Zofran (ondansetron) can make your heart rhythm abnormal by prolonging the QT interval. Using them together increases this risk, which in rare cases can cause a life-threatening heart rhythm called torsades de pointes.
Additive QT prolongation: both citalopram and ondansetron independently prolong the QT interval. FDA issued safety communication for citalopram (2011) limiting max dose to 40mg (20mg in elderly) due to QT risk.
If you take Celexa and need anti-nausea medication, tell your doctor. Alternative anti-nausea medications that do not prolong QT may be available (like metoclopramide or ginger).
Take Citalopram at the same time each day — morning is most common to avoid sleep disruption. Ondansetron follows its prescribed schedule. SSRIs have a long half-life, so consistency matters more than the exact hour.
Higher risk for: elderly, those on multiple serotonergic drugs, people with liver impairment, CYP2D6 poor metabolizers, recent dose changes, or concurrent use of MAOIs or triptans.
Dizziness, fainting, irregular or rapid heartbeat, shortness of breath, sudden collapse
Ask about alternative anti-nausea medications. If both are necessary, discuss ECG monitoring. Ensure citalopram dose does not exceed 40mg/day (20mg if over 60).
Discuss this combination with your prescriber. They may adjust timing, dosing, or switch to an alternative with fewer interaction risks. Never stop an antidepressant abruptly — taper under medical guidance.
Both Celexa (citalopram) and Zofran (ondansetron) can make your heart rhythm abnormal by prolonging the QT interval. Using them together increases this risk, which in rare cases can cause a life-threatening heart rhythm called torsades de pointes.
Take Citalopram at the same time each day — morning is most common to avoid sleep disruption. Ondansetron follows its prescribed schedule. SSRIs have a long half-life, so consistency matters more than the exact hour.
Dizziness, fainting, irregular or rapid heartbeat, shortness of breath, sudden collapse
Discuss this combination with your prescriber. They may adjust timing, dosing, or switch to an alternative with fewer interaction risks. Never stop an antidepressant abruptly — taper under medical guidance.
Ask about alternative anti-nausea medications. If both are necessary, discuss ECG monitoring. Ensure citalopram dose does not exceed 40mg/day (20mg if over 60).
Or browse the full interaction database (121,000+ pairs).