Citalopram and Pimozide interaction
Citalopram and Pimozide: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Citalopram label · effective 2025-10-07
…(including MAOIs such as linezolid or intravenous methylene blue) because of an increased risk of serotonin syndrome [see Warnings and Precautions ( 5.3 ), Drug Interactions ( 7 )] . taking pimozide because of risk of QT prolongation [see Drug Interactions ( 7 )] . with known hypersensitivity to citalopram or any of the inactive ingredients in Citalopram Capsules.
Intervention: Citalopram Capsules is contraindicated in patients taking pimozide [see Contraindications ( 4 ), Warnings and Precautions ( 5.2 )] .
Intervention: Avoid concomitant use of Citalopram Capsules with drugs that prolong the QT interval (Citalopram Capsules is contraindicated in patients taking pimozide) [see Contraindications ( 4 ), Warnings and Precautions ( 5.2 )] .
Pimozide Clinical Impact: Concomitant use of citalopram with pimozide increases plasma concentrations of pimozide, a drug with a narrow therapeutic index, and may increase the risk of QT prolongation and/or ventricular arrhythmias compared to use of citalopram alone [see Clinical Pharmacology ( 12.3 )].
From the Pimozide label · effective 2026-08-12
Concomitant use in patients taking Celexa or Lexapro is contraindicated (see PRECAUTIONS - DRUG INTERACTIONS - Pimozide and Celexa ).
Concomitant use of Pimozide and Celexa or Lexapro is contraindicated (See CONTRAINDICATIONS ).
Because pimozide prolongs the QT interval of the electrocardiogram it is contraindicated in patients with congenital long QT syndrome, patients with a history of cardiac arrhythmias, patients taking other drugs which prolong the QT interval of the electrocardiogram or patients with known hypokalemia or hypomagnesemia (see also PRECAUTIONS - DRUG INTERACTIONS ).
Pimozide and Celexa: In a controlled study, a single dose of pimozide 2 mg coadministered with racemic citalopram 40 mg given once daily for 11 days was associated with a mean increase in QTc values of approximately 10 msec compared to pimozide given alone.
DRUG INTERACTIONS Because pimozide prolongs the QT interval of the electrocardiogram, an additive effect on QT interval would be anticipated if administered with other drugs, such as phenothiazines, tricyclic antidepressants or antiarrhythmic agents, which prolong the QT interval.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.