Promethazine and Ziprasidone interaction

Promethazine and Ziprasidone: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Ziprasidone (Geodon) label · effective 2025-01-13

Major

…drugs, ziprasidone is contraindicated: • in patients with a known history of QT prolongation (including congenital long QT syndrome) • in patients with recent acute myocardial infarction • in patients with uncompensated heart failure Pharmacokinetic/pharmacodynamic studies between ziprasidone and other drugs that prolong the QT interval have not been performed.

Contraindicationsby drug classView label on DailyMed
Major

An additive effect of ziprasidone and other drugs that prolong the QT interval cannot be excluded.

Contraindicationsby drug classView label on DailyMed
Major

QT Prolongation and Risk of Sudden Death Ziprasidone use should be avoided in combination with other drugs that are known to prolong the QTc interval [see Contraindications (4.1) and Drug Interactions (7.4) ] .

Warnings and precautionsby drug classView label on DailyMed
Moderate

Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever, and primary central nervous system (CNS) pathology.

Warnings and precautionsby drug classView label on DailyMed
Minor

Most patients improved promptly with adjunctive treatment with antihistamines or steroids and/or upon discontinuation of ziprasidone, and all patients experiencing these reactions were reported to recover completely.

Warnings and precautionsby drug classView label on DailyMed

From the Promethazine (PROMETHAZINE HYDROCHLORIDE) label · effective 2026-04-16

Moderate

The impairment may be amplified by concomitant use of other central-nervous-system depressants such as alcohol, sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers; therefore such agents should either be eliminated or given in reduced dosage in the presence of promethazine…

Warningsby drug classView label on DailyMed
Moderate

The management of NMS should include 1) immediate discontinuation of promethazine HCl, antipsychotic drugs, if any, and other drugs not essential to concurrent therapy, 2) intensive symptomatic treatment and medical monitoring, and 3) treatment of any concomitant serious medical problems for which specific treatments are available.

Warningsby drug classView label on DailyMed
Moderate

Drug Interactions CNS Depressants Promethazine Syrup may increase, prolong, or intensify the sedative action of other central-nervous-system depressants, such as alcohol, sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers; therefore, such agents should be avoided or administered…

Drug interactionsby drug classView label on DailyMed
Moderate

CNS Depressants Promethazine Syrup may increase, prolong, or intensify the sedative action of other central-nervous-system depressants, such as alcohol, sedatives/hypnotics (including barbiturates), narcotics, narcotic analgesics, general anesthetics, tricyclic antidepressants, and tranquilizers; therefore, such agents should be avoided or administered in reduced…

Drug interactionsby drug classView label on DailyMed
Minor

Neuroleptic Malignant Syndrome A potentially fatal symptom complex sometimes referred to as Neuroleptic Malignant Syndrome (NMS) has been reported in association with promethazine HCl alone or in combination with antipsychotic drugs.

Warningsby drug classView label on DailyMed

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Not 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.