Drug interactions
Phentermine + Ziprasidone
Severity: Moderate
Phentermine and Ziprasidone: 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 that can raise heart rate and blood pressure, while ziprasidone prolongs the QT interval. The combination could add to arrhythmic risk, and the stimulant effect may partly offset ziprasidone sedation.
What this interaction means in plain words
Phentermine and Ziprasidone 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 belongs to Central Nervous System; Ziprasidone belongs to Central Nervous System.
Why it happens
Additive cardiovascular effects with pharmacodynamic opposition on CNS activity.
What to do
Monitor heart rate, blood pressure and palpitations, and obtain an ECG if cardiac risk factors exist. Use an alternative weight-loss approach in patients with QT prolongation.
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 Ziprasidone
- Amiodarone + Ziprasidone Contraindicated
- Amitriptyline + Ziprasidone Contraindicated
- Arsenic trioxide + Ziprasidone Contraindicated
- Bedaquiline + Ziprasidone Contraindicated
- Chloroquine + Ziprasidone Contraindicated
- Citalopram + Ziprasidone Contraindicated
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 Phentermine with Ziprasidone?
MediHelp rates the interaction as moderate. Phentermine and Ziprasidone 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 that can raise heart rate and blood pressure, while ziprasidone prolongs the QT interval. The combination could add to arrhythmic risk, and the stimulant effect may partly offset ziprasidone sedation.
How serious is the interaction between Phentermine and Ziprasidone?
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 heart rate, blood pressure and palpitations, and obtain an ECG if cardiac risk factors exist. Use an alternative weight-loss approach in patients with QT prolongation.
What other medicines interact with Ziprasidone?
MediHelp also lists interactions of Ziprasidone with, for example, Amiodarone, Amitriptyline, Arsenic trioxide. The full list is on the Ziprasidone page.
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