Drug interactions
Fluphenazine + Phentermine
Severity: Moderate
Fluphenazine 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, while fluphenazine is a dopamine antagonist, so their effects may partly oppose each other. Both can influence cardiovascular function, and stimulants may aggravate psychotic symptoms. Clinical data on the combination are limited.
What this interaction means in plain words
Fluphenazine 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.
Fluphenazine belongs to Central Nervous System; Phentermine belongs to Central Nervous System.
Why it happens
Opposing dopaminergic and adrenergic pharmacology with possible additive cardiovascular effects; mechanism not firmly established.
What to do
Monitor blood pressure, heart rate and psychiatric symptoms. Avoid in patients with arrhythmia or unstable psychosis.
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 Fluphenazine
- Arsenic trioxide + Fluphenazine Contraindicated
- Dofetilide + Fluphenazine Contraindicated
- Fluphenazine + Ibutilide Contraindicated
- Fluphenazine + Pimozide Contraindicated
- Adagrasib + Fluphenazine Major
- Alfentanil + Fluphenazine 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 Fluphenazine with Phentermine?
MediHelp rates the interaction as moderate. Fluphenazine 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, while fluphenazine is a dopamine antagonist, so their effects may partly oppose each other. Both can influence cardiovascular function, and stimulants may aggravate psychotic symptoms. Clinical data on the combination are limited.
How serious is the interaction between Fluphenazine 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 psychiatric symptoms. Avoid in patients with arrhythmia or unstable psychosis.
What other medicines interact with Fluphenazine?
MediHelp also lists interactions of Fluphenazine with, for example, Arsenic trioxide, Dofetilide, Ibutilide. The full list is on the Fluphenazine page.
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