Drug interactions
Saquinavir + Venlafaxine
Severity: Major
Saquinavir and Venlafaxine: major 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
Saquinavir prolongs the QT and PR intervals, and as a CYP3A4 inhibitor it may modestly raise venlafaxine exposure. Together they may increase the risk of QT prolongation and arrhythmia.
What this interaction means in plain words
Saquinavir and Venlafaxine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive QT prolongation, with CYP3A4 inhibition by saquinavir possibly increasing venlafaxine concentrations.
What to do
Obtain a baseline ECG and monitor the QTc, and correct electrolyte abnormalities. Consider an alternative antidepressant if the QTc becomes prolonged.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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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
Frequently asked questions
Can I take Saquinavir with Venlafaxine?
MediHelp rates the interaction as major. Saquinavir and Venlafaxine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Saquinavir prolongs the QT and PR intervals, and as a CYP3A4 inhibitor it may modestly raise venlafaxine exposure. Together they may increase the risk of QT prolongation and arrhythmia.
How serious is the interaction between Saquinavir and Venlafaxine?
MediHelp rates it major, 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 monitor the QTc, and correct electrolyte abnormalities. Consider an alternative antidepressant if the QTc becomes prolonged.
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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