Drug interactions
Cilostazol + Efavirenz
Severity: Moderate
Cilostazol and Efavirenz: 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
Efavirenz may lower cilostazol exposure through CYP3A4 induction, while its CYP2C19 inhibitory effect may raise levels of the active metabolite 3,4-dehydrocilostazol. The net effect on efficacy and on adverse effects such as headache, tachycardia and palpitations is unpredictable.
What this interaction means in plain words
Cilostazol and Efavirenz 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.
Cilostazol belongs to Cardiovascular; Efavirenz belongs to Anti Virals.
Why it happens
Efavirenz induces CYP3A4 and can inhibit CYP2C19, altering formation and clearance of cilostazol and its active metabolite.
What to do
Monitor for loss of effect on claudication symptoms and for cilostazol adverse effects such as tachycardia and headache. Adjust the cilostazol dose according to response and tolerability.
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 Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Other interactions of Cilostazol
Frequently asked questions
Can I take Cilostazol with Efavirenz?
MediHelp rates the interaction as moderate. Cilostazol and Efavirenz 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. Efavirenz may lower cilostazol exposure through CYP3A4 induction, while its CYP2C19 inhibitory effect may raise levels of the active metabolite 3,4-dehydrocilostazol. The net effect on efficacy and on adverse effects such as headache, tachycardia and palpitations is unpredictable.
How serious is the interaction between Cilostazol and Efavirenz?
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 effect on claudication symptoms and for cilostazol adverse effects such as tachycardia and headache. Adjust the cilostazol dose according to response and tolerability.
What other medicines interact with Efavirenz?
MediHelp also lists interactions of Efavirenz with, for example, Cobimetinib, Dienogest / estradiol valerate, Dihydroergotamine intranasal. The full list is on the Efavirenz page.
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