Drug interactions
Nafcillin + Progesterone
Severity: Moderate
Nafcillin and Progesterone: 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
Nafcillin may induce CYP3A4 and lower systemic progesterone exposure. This could reduce the effect of progesterone, for example on endometrial protection, luteal support or contraception.
What this interaction means in plain words
Nafcillin and Progesterone 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
Nafcillin induces hepatic and intestinal CYP3A4, increasing progesterone metabolism.
What to do
Monitor for loss of progestogenic effect such as breakthrough bleeding or inadequate luteal support, and increase the progesterone dose if needed. Consider a non-penicillinase-resistant alternative antibiotic if prolonged therapy is required.
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 Progesterone
Frequently asked questions
Can I take Nafcillin with Progesterone?
MediHelp rates the interaction as moderate. Nafcillin and Progesterone 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. Nafcillin may induce CYP3A4 and lower systemic progesterone exposure. This could reduce the effect of progesterone, for example on endometrial protection, luteal support or contraception.
How serious is the interaction between Nafcillin and Progesterone?
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 for loss of progestogenic effect such as breakthrough bleeding or inadequate luteal support, and increase the progesterone dose if needed. Consider a non-penicillinase-resistant alternative antibiotic if prolonged therapy is required.
What other medicines interact with Progesterone?
MediHelp also lists interactions of Progesterone with, for example, Apalutamide, Carbamazepine, Enzalutamide. The full list is on the Progesterone page.
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