Drug interactions
Procarbazine + Promethazine
Severity: Moderate
Procarbazine and Promethazine: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both drugs depress the central nervous system, so using them together can cause excessive drowsiness and impaired alertness. Procarbazine also has weak MAO-inhibiting properties and can intensify the effects of CNS depressants.
What this interaction means in plain words
Procarbazine and Promethazine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Procarbazine belongs to Oncology; Promethazine belongs to Respiratory.
Why it happens
Additive CNS depression from the sedating antihistamine and procarbazine, which also has weak monoamine oxidase inhibitory activity.
What to do
Start promethazine at the lowest effective dose and monitor for oversedation and confusion. Advise patients to avoid driving and alcohol.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Promethazine
- Ibutilide + Promethazine Contraindicated
- Pimozide + Promethazine Contraindicated
- Promethazine + Thioridazine Contraindicated
- Alfentanil + Promethazine Major
- Amiodarone + Promethazine Major
- Amisulpride + Promethazine Major
Other interactions of Procarbazine
- Adenovirus types 4 and 7 live + Procarbazine Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amoxapine + Procarbazine Contraindicated
- Atomoxetine + Procarbazine Contraindicated
- Bcg vaccine live + Procarbazine Contraindicated
- Brimonidine + Procarbazine Contraindicated
Frequently asked questions
Can I take Procarbazine with Promethazine?
MediHelp rates the interaction as moderate. Procarbazine and Promethazine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both drugs depress the central nervous system, so using them together can cause excessive drowsiness and impaired alertness. Procarbazine also has weak MAO-inhibiting properties and can intensify the effects of CNS depressants.
How serious is the interaction between Procarbazine and Promethazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start promethazine at the lowest effective dose and monitor for oversedation and confusion. Advise patients to avoid driving and alcohol.
What other medicines interact with Promethazine?
MediHelp also lists interactions of Promethazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Promethazine page.
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