Drug interactions
Efavirenz + Levofloxacin
Severity: Moderate
Efavirenz and Levofloxacin: 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 levofloxacin adds to this effect. The combination may modestly increase arrhythmia risk in susceptible patients.
What this interaction means in plain words
Efavirenz and Levofloxacin 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; Levofloxacin belongs to Anti Bacterial.
Why it happens
Additive QT prolongation; efavirenz effects are concentration-related.
What to do
Check a baseline ECG and electrolytes, especially in patients with other QT risk factors or CYP2B6 slow-metabolizer status. Monitor the QTc during combined use.
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 Levofloxacin
- Dronedarone + Levofloxacin Contraindicated
- Ibutilide + Levofloxacin Contraindicated
- Levofloxacin + Thioridazine Contraindicated
- Levofloxacin + Vandetanib Contraindicated
- Levofloxacin + Ziprasidone Contraindicated
- Adagrasib + Levofloxacin 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 Levofloxacin?
MediHelp rates the interaction as moderate. Efavirenz and Levofloxacin 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 levofloxacin adds to this effect. The combination may modestly increase arrhythmia risk in susceptible patients.
How serious is the interaction between Efavirenz and Levofloxacin?
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 a baseline ECG and electrolytes, especially in patients with other QT risk factors or CYP2B6 slow-metabolizer status. Monitor the QTc during combined use.
What other medicines interact with Levofloxacin?
MediHelp also lists interactions of Levofloxacin with, for example, Dronedarone, Ibutilide, Thioridazine. The full list is on the Levofloxacin page.
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