Drug interactions
Phenelzine + Phentermine
Severity: Contraindicated
Phenelzine and Phentermine: contraindicated 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 releases norepinephrine and with an MAOI can precipitate hypertensive crisis. Labeling contraindicates its use during or within 14 days of an MAOI.
What this interaction means in plain words
Phenelzine and Phentermine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Phenelzine belongs to Central Nervous System; Phentermine belongs to Central Nervous System.
Why it happens
Sympathomimetic amine-induced norepinephrine release is potentiated by irreversible MAO inhibition.
What to do
Avoid combination; wait at least 14 days after stopping phenelzine before starting phentermine. Choose alternative weight-loss therapy.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Phenelzine
- 5-HTP + Phenelzine Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amoxapine + Phenelzine Contraindicated
- Atomoxetine + Phenelzine Contraindicated
- Benzphetamine + Phenelzine Contraindicated
- Brimonidine + Phenelzine Contraindicated
Other interactions of Phentermine
- Isocarboxazid + Phentermine Contraindicated
- Linezolid + Phentermine Contraindicated
- Phentermine + Procarbazine Contraindicated
- Phentermine + Rasagiline Contraindicated
- Phentermine + Selegiline Contraindicated
- Phentermine + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Phenelzine with Phentermine?
MediHelp rates the interaction as contraindicated. Phenelzine and Phentermine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Phentermine releases norepinephrine and with an MAOI can precipitate hypertensive crisis. Labeling contraindicates its use during or within 14 days of an MAOI.
How serious is the interaction between Phenelzine and Phentermine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combination; wait at least 14 days after stopping phenelzine before starting phentermine. Choose alternative weight-loss therapy.
What other medicines interact with Phenelzine?
MediHelp also lists interactions of Phenelzine with, for example, 5-HTP, Amitriptyline, Amoxapine. The full list is on the Phenelzine page.
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