Drug interactions
Amitriptyline + Efavirenz
Severity: Moderate
Amitriptyline and Efavirenz: 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 alter amitriptyline exposure through effects on CYP enzymes, with an uncertain net effect. Both drugs may prolong the QT interval, and efavirenz also has CNS effects that overlap with amitriptyline.
What this interaction means in plain words
Amitriptyline and Efavirenz 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.
Amitriptyline belongs to Central Nervous System; Efavirenz belongs to Anti Virals.
Why it happens
Mixed CYP effects (CYP3A4 induction, variable CYP2C19 effect) plus additive QT prolongation.
What to do
Obtain a baseline ECG and correct electrolytes. Monitor for antidepressant response, anticholinergic effects and arrhythmia symptoms, adjusting amitriptyline by clinical response or levels.
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 Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Efavirenz?
MediHelp rates the interaction as moderate. Amitriptyline and Efavirenz 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 alter amitriptyline exposure through effects on CYP enzymes, with an uncertain net effect. Both drugs may prolong the QT interval, and efavirenz also has CNS effects that overlap with amitriptyline.
How serious is the interaction between Amitriptyline and Efavirenz?
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 correct electrolytes. Monitor for antidepressant response, anticholinergic effects and arrhythmia symptoms, adjusting amitriptyline by clinical response or levels.
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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