Drug interactions
Efavirenz + Granisetron
Severity: Moderate
Efavirenz and Granisetron: 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 can prolong the QT interval, particularly at higher exposures, and granisetron has a modest QT effect of its own. Together they may increase the likelihood of arrhythmia in at-risk patients.
What this interaction means in plain words
Efavirenz and Granisetron 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; Granisetron belongs to Gastrointestinal Tract.
Why it happens
Additive QT prolongation; efavirenz may also induce CYP3A4 and reduce granisetron exposure.
What to do
Check ECG and electrolytes if other risk factors for QT prolongation are present. Monitor for reduced antiemetic effect and arrhythmic symptoms.
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 Granisetron
- Apomorphine + Granisetron Contraindicated
- Amiodarone + Granisetron Major
- Amisulpride + Granisetron Major
- Arsenic trioxide + Granisetron Major
- Artemether / lumefantrine + Granisetron Major
- Artemether + Granisetron Major
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
Frequently asked questions
Can I take Efavirenz with Granisetron?
MediHelp rates the interaction as moderate. Efavirenz and Granisetron 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 can prolong the QT interval, particularly at higher exposures, and granisetron has a modest QT effect of its own. Together they may increase the likelihood of arrhythmia in at-risk patients.
How serious is the interaction between Efavirenz and Granisetron?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check ECG and electrolytes if other risk factors for QT prolongation are present. Monitor for reduced antiemetic effect and arrhythmic symptoms.
What other medicines interact with Granisetron?
MediHelp also lists interactions of Granisetron with, for example, Apomorphine, Amiodarone, Amisulpride. The full list is on the Granisetron page.
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