Drug interactions
Efavirenz + Primaquine
Severity: Moderate
Efavirenz and Primaquine: 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 induce CYP-mediated metabolism of primaquine, altering exposure to the parent and active metabolites. Both drugs may also prolong the QT interval.
What this interaction means in plain words
Efavirenz and Primaquine 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 belongs to Anti Virals; Primaquine belongs to Anti Parasitic.
Why it happens
Efavirenz induction of CYP3A4/CYP2D-related pathways plus additive QT prolongation.
What to do
Obtain a baseline ECG and monitor QTc during therapy. Monitor for malaria treatment response and hemolysis where relevant.
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 Primaquine
- Pimozide + Primaquine Contraindicated
- Amiodarone + Primaquine Major
- Amisulpride + Primaquine Major
- Anagrelide + Primaquine Major
- Arsenic trioxide + Primaquine Major
- Asenapine + Primaquine Major
Frequently asked questions
Can I take Efavirenz with Primaquine?
MediHelp rates the interaction as moderate. Efavirenz and Primaquine 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 induce CYP-mediated metabolism of primaquine, altering exposure to the parent and active metabolites. Both drugs may also prolong the QT interval.
How serious is the interaction between Efavirenz and Primaquine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and monitor QTc during therapy. Monitor for malaria treatment response and hemolysis where relevant.
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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