Drug interactions
Efavirenz + Solifenacin
Severity: Moderate
Efavirenz and Solifenacin: 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 induces CYP3A4 and may lower solifenacin levels, potentially reducing efficacy. Efavirenz can also prolong the QT interval, so combined QT effects are theoretically possible.
What this interaction means in plain words
Efavirenz and Solifenacin 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; Solifenacin belongs to Genitourinary.
Why it happens
CYP3A4 induction by efavirenz reduces solifenacin exposure, with additive QT prolongation potential.
What to do
Monitor bladder symptom response and increase the solifenacin dose within the labeled range if needed. Check an ECG if other QT risk factors are present.
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 Solifenacin
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 Solifenacin?
MediHelp rates the interaction as moderate. Efavirenz and Solifenacin 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 induces CYP3A4 and may lower solifenacin levels, potentially reducing efficacy. Efavirenz can also prolong the QT interval, so combined QT effects are theoretically possible.
How serious is the interaction between Efavirenz and Solifenacin?
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 bladder symptom response and increase the solifenacin dose within the labeled range if needed. Check an ECG if other QT risk factors are present.
What other medicines interact with Solifenacin?
MediHelp also lists interactions of Solifenacin with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Solifenacin page.
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