Drug interactions
Macimorelin + Phenytoin
Severity: Moderate
Macimorelin and Phenytoin: 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
Strong CYP3A4 inducers such as phenytoin may lower macimorelin levels and distort the growth hormone stimulation test. This can yield a false positive diagnosis of growth hormone deficiency.
What this interaction means in plain words
Macimorelin and Phenytoin 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.
Macimorelin belongs to Endocrine; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, lowering macimorelin exposure and the stimulated GH response.
What to do
If clinically possible, stop phenytoin with an adequate washout period before testing. Otherwise interpret the test cautiously or use an alternative diagnostic.
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 Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Macimorelin
Frequently asked questions
Can I take Macimorelin with Phenytoin?
MediHelp rates the interaction as moderate. Macimorelin and Phenytoin 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. Strong CYP3A4 inducers such as phenytoin may lower macimorelin levels and distort the growth hormone stimulation test. This can yield a false positive diagnosis of growth hormone deficiency.
How serious is the interaction between Macimorelin and Phenytoin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: If clinically possible, stop phenytoin with an adequate washout period before testing. Otherwise interpret the test cautiously or use an alternative diagnostic.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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