Drug interactions
Metformin + Perphenazine
Severity: Moderate
Metformin and Perphenazine: 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
Phenothiazines can raise blood glucose and impair glucose tolerance, which may reduce the effectiveness of metformin. Glycemic control may worsen after perphenazine is started and improve when it is stopped.
What this interaction means in plain words
Metformin and Perphenazine 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.
Metformin belongs to Endocrine; Perphenazine belongs to Central Nervous System.
Why it happens
Pharmacodynamic antagonism, as antipsychotics can impair glucose tolerance and insulin sensitivity.
What to do
Monitor blood glucose and HbA1c after starting, changing or stopping perphenazine. Adjust the metformin dose as needed.
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 Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Other interactions of Metformin
Frequently asked questions
Can I take Metformin with Perphenazine?
MediHelp rates the interaction as moderate. Metformin and Perphenazine 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. Phenothiazines can raise blood glucose and impair glucose tolerance, which may reduce the effectiveness of metformin. Glycemic control may worsen after perphenazine is started and improve when it is stopped.
How serious is the interaction between Metformin and Perphenazine?
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 and HbA1c after starting, changing or stopping perphenazine. Adjust the metformin dose as needed.
What other medicines interact with Perphenazine?
MediHelp also lists interactions of Perphenazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Perphenazine page.
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