Drug interactions
Efavirenz + Fluvoxamine
Severity: Moderate
Efavirenz and Fluvoxamine: 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
Fluvoxamine may raise efavirenz concentrations, which could increase CNS adverse effects such as dizziness and sleep disturbance. Both drugs can also prolong the QT interval.
What this interaction means in plain words
Efavirenz and Fluvoxamine 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; Fluvoxamine belongs to Central Nervous System.
Why it happens
Fluvoxamine inhibits CYP2C19 and other pathways involved in efavirenz clearance, plus additive QT prolongation.
What to do
Monitor for neuropsychiatric effects and consider an ECG in patients with QT risk factors. Reduce the fluvoxamine dose or choose an alternative SSRI if problems occur.
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 Fluvoxamine
- Agomelatine + Fluvoxamine Contraindicated
- Alosetron + Fluvoxamine Contraindicated
- Fezolinetant + Fluvoxamine Contraindicated
- Fluvoxamine + Isocarboxazid Contraindicated
- Fluvoxamine + Mavacamten Contraindicated
- Fluvoxamine + Methylene blue Contraindicated
Frequently asked questions
Can I take Efavirenz with Fluvoxamine?
MediHelp rates the interaction as moderate. Efavirenz and Fluvoxamine 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. Fluvoxamine may raise efavirenz concentrations, which could increase CNS adverse effects such as dizziness and sleep disturbance. Both drugs can also prolong the QT interval.
How serious is the interaction between Efavirenz and Fluvoxamine?
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 neuropsychiatric effects and consider an ECG in patients with QT risk factors. Reduce the fluvoxamine dose or choose an alternative SSRI if problems occur.
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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