Drug interactions
Phenelzine + Tolbutamide
Severity: Moderate
Phenelzine and Tolbutamide: 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
MAO inhibitors can enhance the blood glucose-lowering effect of sulfonylureas. Adding phenelzine to tolbutamide may therefore precipitate hypoglycemia.
What this interaction means in plain words
Phenelzine and Tolbutamide 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.
Phenelzine belongs to Central Nervous System; Tolbutamide belongs to Endocrine.
Why it happens
MAO inhibitors may enhance insulin secretion or sensitivity and alter glucose homeostasis, producing an additive hypoglycemic effect; the exact mechanism is not fully established.
What to do
Monitor blood glucose closely when phenelzine is started, changed or stopped, and reduce the tolbutamide dose if hypoglycemia occurs. Teach patients to recognize hypoglycemia symptoms.
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
Other interactions of Tolbutamide
- Glyburide-metformin + Tolbutamide Major
- Insulin degludec-liraglutide + Tolbutamide Major
- Aceclofenac + Tolbutamide Moderate
- Acemetacin + Tolbutamide Moderate
- Acetylsalicylic acid + Tolbutamide Moderate
- Albiglutide + Tolbutamide Moderate
Frequently asked questions
Can I take Phenelzine with Tolbutamide?
MediHelp rates the interaction as moderate. Phenelzine and Tolbutamide 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. MAO inhibitors can enhance the blood glucose-lowering effect of sulfonylureas. Adding phenelzine to tolbutamide may therefore precipitate hypoglycemia.
How serious is the interaction between Phenelzine and Tolbutamide?
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 glucose closely when phenelzine is started, changed or stopped, and reduce the tolbutamide dose if hypoglycemia occurs. Teach patients to recognize hypoglycemia symptoms.
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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