Drug interactions
Phentermine + Risperidone
Severity: Minor
Phentermine and Risperidone: minor 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 may counteract risperidone's sedation. It may also aggravate agitation or psychotic symptoms and add to cardiovascular effects. The combination has little direct evidence.
What this interaction means in plain words
Phentermine and Risperidone have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Phentermine belongs to Central Nervous System; Risperidone belongs to Central Nervous System.
Why it happens
Opposing pharmacodynamic effects of sympathomimetic stimulation and antipsychotic receptor antagonism.
What to do
Monitor mental state, heart rate and blood pressure. Avoid phentermine in patients with unstable psychosis.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Risperidone
- Ibutilide + Risperidone Contraindicated
- Risperidone + Vandetanib Contraindicated
- Adagrasib + Risperidone Major
- Amiodarone + Risperidone Major
- Amisulpride + Risperidone Major
- Amoxapine + Risperidone 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 Phentermine with Risperidone?
MediHelp rates the interaction as minor. Phentermine and Risperidone have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Phentermine is a sympathomimetic stimulant that may counteract risperidone's sedation. It may also aggravate agitation or psychotic symptoms and add to cardiovascular effects. The combination has little direct evidence.
How serious is the interaction between Phentermine and Risperidone?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor mental state, heart rate and blood pressure. Avoid phentermine in patients with unstable psychosis.
What other medicines interact with Risperidone?
MediHelp also lists interactions of Risperidone with, for example, Ibutilide, Vandetanib, Adagrasib. The full list is on the Risperidone page.
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