Drug interactions
Perphenazine + Phentermine
Severity: Moderate
Perphenazine and Phentermine: 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
Phentermine is a sympathomimetic stimulant, whereas perphenazine is a sedating antipsychotic with QT-prolonging and seizure-threshold-lowering potential. The combination may raise cardiovascular risk and blunt the effects of each drug.
What this interaction means in plain words
Perphenazine and Phentermine 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.
Perphenazine belongs to Central Nervous System; Phentermine belongs to Central Nervous System.
Why it happens
Opposing CNS effects and possible additive cardiovascular and arrhythmic effects; mechanism not firmly established.
What to do
Monitor blood pressure, heart rate and mental status. Avoid in patients with arrhythmia or uncontrolled hypertension.
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 Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Other interactions of Phentermine
- Isocarboxazid + Phentermine Contraindicated
- Linezolid + Phentermine Contraindicated
- Phenelzine + Phentermine Contraindicated
- Phentermine + Procarbazine Contraindicated
- Phentermine + Rasagiline Contraindicated
- Phentermine + Selegiline Contraindicated
Frequently asked questions
Can I take Perphenazine with Phentermine?
MediHelp rates the interaction as moderate. Perphenazine and Phentermine 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. Phentermine is a sympathomimetic stimulant, whereas perphenazine is a sedating antipsychotic with QT-prolonging and seizure-threshold-lowering potential. The combination may raise cardiovascular risk and blunt the effects of each drug.
How serious is the interaction between Perphenazine and Phentermine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure, heart rate and mental status. Avoid in patients with arrhythmia or uncontrolled hypertension.
What other medicines interact with Perphenazine?
MediHelp also lists interactions of Perphenazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Perphenazine page.
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