Drug interactions
Mestranol + Zafirlukast
Severity: Minor
Mestranol and Zafirlukast: minor 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
Mestranol is a prodrug of ethinylestradiol and is metabolized partly via CYP3A4. Zafirlukast's weak CYP3A4 inhibition might slightly increase estrogen exposure. Clinically meaningful effects are unlikely.
What this interaction means in plain words
Mestranol and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Weak CYP3A4 inhibition by zafirlukast may reduce estrogen clearance.
What to do
No action is usually needed. Be alert for estrogenic adverse effects such as breast tenderness, nausea or hypertension.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Zafirlukast
- Pimozide + Zafirlukast Contraindicated
- Lomitapide + Zafirlukast Major
- Nilotinib + Zafirlukast Major
- Warfarin + Zafirlukast Major
- Apalutamide + Zafirlukast Moderate
- Carbamazepine + Zafirlukast Moderate
Frequently asked questions
Can I take Mestranol with Zafirlukast?
MediHelp rates the interaction as minor. Mestranol and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Mestranol is a prodrug of ethinylestradiol and is metabolized partly via CYP3A4. Zafirlukast's weak CYP3A4 inhibition might slightly increase estrogen exposure. Clinically meaningful effects are unlikely.
How serious is the interaction between Mestranol and Zafirlukast?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No action is usually needed. Be alert for estrogenic adverse effects such as breast tenderness, nausea or hypertension.
What other medicines interact with Zafirlukast?
MediHelp also lists interactions of Zafirlukast with, for example, Pimozide, Lomitapide, Nilotinib. The full list is on the Zafirlukast page.
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