Drug interactions
Isoflurane + Venlafaxine
Severity: Moderate
Isoflurane and Venlafaxine: 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
Isoflurane can prolong the QT interval, and venlafaxine has a small QT effect. Together they may increase the risk of perioperative arrhythmia in susceptible patients.
What this interaction means in plain words
Isoflurane and Venlafaxine 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.
Isoflurane belongs to Central Nervous System; Venlafaxine belongs to Central Nervous System.
Why it happens
Additive effects on cardiac repolarisation.
What to do
Continue venlafaxine through surgery to avoid withdrawal, with a baseline ECG and normal electrolytes. Monitor the ECG intraoperatively if other QT risk factors exist.
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 Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Other interactions of Isoflurane
Frequently asked questions
Can I take Isoflurane with Venlafaxine?
MediHelp rates the interaction as moderate. Isoflurane and Venlafaxine 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. Isoflurane can prolong the QT interval, and venlafaxine has a small QT effect. Together they may increase the risk of perioperative arrhythmia in susceptible patients.
How serious is the interaction between Isoflurane and Venlafaxine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Continue venlafaxine through surgery to avoid withdrawal, with a baseline ECG and normal electrolytes. Monitor the ECG intraoperatively if other QT risk factors exist.
What other medicines interact with Venlafaxine?
MediHelp also lists interactions of Venlafaxine with, for example, Isocarboxazid, Methylene blue, Phenelzine. The full list is on the Venlafaxine page.
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