Drug interactions
Meperidine + Phentermine
Severity: Moderate
Meperidine 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 stimulant that may partly counteract opioid sedation, but the net effect varies between patients. Combining a sympathomimetic with meperidine, which has serotonergic properties, may raise the risk of agitation, hypertension and tachycardia.
What this interaction means in plain words
Meperidine 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.
Meperidine belongs to Musculoskeletal; Phentermine belongs to Central Nervous System.
Why it happens
Opposing CNS effects with possible additive sympathomimetic and serotonergic activity; the interaction is not well defined.
What to do
Monitor blood pressure, heart rate and mental status when the two are used together. Watch for serotonergic symptoms and do not assume the stimulant protects against respiratory depression.
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 Meperidine
- Alvimopan + Meperidine Contraindicated
- Isocarboxazid + Meperidine Contraindicated
- Meperidine + Methylene blue Contraindicated
- Meperidine + Olanzapine / samidorphan Contraindicated
- Meperidine + Phenelzine Contraindicated
- Meperidine + Procarbazine 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 Meperidine with Phentermine?
MediHelp rates the interaction as moderate. Meperidine 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 stimulant that may partly counteract opioid sedation, but the net effect varies between patients. Combining a sympathomimetic with meperidine, which has serotonergic properties, may raise the risk of agitation, hypertension and tachycardia.
How serious is the interaction between Meperidine 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 when the two are used together. Watch for serotonergic symptoms and do not assume the stimulant protects against respiratory depression.
What other medicines interact with Meperidine?
MediHelp also lists interactions of Meperidine with, for example, Alvimopan, Isocarboxazid, Methylene blue. The full list is on the Meperidine page.
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