Drug interactions
Metformin + Olanzapine
Severity: Moderate
Metformin and Olanzapine: 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
Olanzapine can cause hyperglycemia, weight gain and insulin resistance that may counteract the glucose-lowering effect of metformin. Metformin is also used to limit antipsychotic-induced weight gain, so the combination is often useful but needs metabolic monitoring.
What this interaction means in plain words
Metformin and Olanzapine 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; Olanzapine belongs to Central Nervous System.
Why it happens
Olanzapine-induced insulin resistance pharmacodynamically opposes metformin's glucose-lowering action.
What to do
Monitor fasting glucose and HbA1c, and adjust the antidiabetic regimen if control worsens. Monitor weight and lipids throughout treatment.
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 Olanzapine
Other interactions of Metformin
Frequently asked questions
Can I take Metformin with Olanzapine?
MediHelp rates the interaction as moderate. Metformin and Olanzapine 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. Olanzapine can cause hyperglycemia, weight gain and insulin resistance that may counteract the glucose-lowering effect of metformin. Metformin is also used to limit antipsychotic-induced weight gain, so the combination is often useful but needs metabolic monitoring.
How serious is the interaction between Metformin and Olanzapine?
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 fasting glucose and HbA1c, and adjust the antidiabetic regimen if control worsens. Monitor weight and lipids throughout treatment.
What other medicines interact with Olanzapine?
MediHelp also lists interactions of Olanzapine with, for example, Amisulpride, Amoxapine, Apomorphine. The full list is on the Olanzapine page.
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