Drug interactions
Pentazocine + Phenelzine
Severity: Contraindicated
Pentazocine and Phenelzine: 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
Phenelzine, an irreversible non-selective MAOI, may cause serotonin syndrome or severe opioid-type reactions with pentazocine, including hypertension or hypotension, hyperthermia, and profound sedation. Effects can be severe and occasionally fatal.
What this interaction means in plain words
Pentazocine and Phenelzine 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.
Pentazocine belongs to Musculoskeletal; Phenelzine belongs to Central Nervous System.
Why it happens
Irreversible MAO inhibition potentiates serotonergic and CNS-depressant effects of pentazocine through an incompletely understood mechanism.
What to do
Do not co-administer, and do not give pentazocine within 14 days of stopping phenelzine. Use a non-opioid or alternative analgesic.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Pentazocine and Phenelzine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Pentazocine
- Calcium / magnesium / potassium / sodium oxybates + Pentazocine Contraindicated
- Olanzapine / samidorphan + Pentazocine Contraindicated
- Pentazocine + Tranylcypromine Contraindicated
- Alfentanil + Pentazocine Major
- Alprazolam + Pentazocine Major
- Alvimopan + Pentazocine Major
Other interactions of Phenelzine
- 5-HTP + Phenelzine Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amoxapine + Phenelzine Contraindicated
- Atomoxetine + Phenelzine Contraindicated
- Benzphetamine + Phenelzine Contraindicated
- Brimonidine + Phenelzine Contraindicated
Frequently asked questions
Can I take Pentazocine with Phenelzine?
MediHelp rates the interaction as contraindicated. Pentazocine and Phenelzine 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, an irreversible non-selective MAOI, may cause serotonin syndrome or severe opioid-type reactions with pentazocine, including hypertension or hypotension, hyperthermia, and profound sedation. Effects can be severe and occasionally fatal.
How serious is the interaction between Pentazocine and Phenelzine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not co-administer, and do not give pentazocine within 14 days of stopping phenelzine. Use a non-opioid or alternative analgesic.
What other medicines interact with Pentazocine?
MediHelp also lists interactions of Pentazocine with, for example, Calcium / magnesium / potassium / sodium oxybates, Olanzapine / samidorphan, Tranylcypromine. The full list is on the Pentazocine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
