Drug interactions
Phenelzine + Thiothixene
Severity: Moderate
Phenelzine and Thiothixene: 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
Combining a monoamine oxidase inhibitor with a dopamine-blocking antipsychotic may raise the risk of serotonin toxicity and neuroleptic malignant syndrome. Both are uncommon but serious, with mental status change, hyperthermia, rigidity and autonomic instability.
What this interaction means in plain words
Phenelzine and Thiothixene 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.
Why it happens
Additive effects of increased monoamine availability from MAO inhibition and D2 receptor blockade; exact mechanism not firmly established.
What to do
Start thiothixene at a low dose and titrate slowly. Monitor for clonus, agitation, fever, rigidity and autonomic instability, and stop both drugs if toxicity is suspected.
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 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 Phenelzine with Thiothixene?
MediHelp rates the interaction as moderate. Phenelzine and Thiothixene 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. Combining a monoamine oxidase inhibitor with a dopamine-blocking antipsychotic may raise the risk of serotonin toxicity and neuroleptic malignant syndrome. Both are uncommon but serious, with mental status change, hyperthermia, rigidity and autonomic instability.
How serious is the interaction between Phenelzine and Thiothixene?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Start thiothixene at a low dose and titrate slowly. Monitor for clonus, agitation, fever, rigidity and autonomic instability, and stop both drugs if toxicity is suspected.
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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