Drug interactions
Saquinavir + Vinblastine
Severity: Major
Saquinavir and Vinblastine: 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, usually given with ritonavir, inhibits CYP3A4 and may increase vinblastine exposure. This raises the risk of myelosuppression, neurotoxicity and constipation or ileus.
What this interaction means in plain words
Saquinavir and Vinblastine 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
Saquinavir inhibits CYP3A4 (and ritonavir booster also inhibits P-glycoprotein), reducing vinblastine clearance.
What to do
Avoid if possible or reduce the vinblastine dose, and monitor blood counts and neurological and bowel function. Consider an antiretroviral with less CYP3A4 inhibition.
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 Vinblastine
Frequently asked questions
Can I take Saquinavir with Vinblastine?
MediHelp rates the interaction as major. Saquinavir and Vinblastine 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, usually given with ritonavir, inhibits CYP3A4 and may increase vinblastine exposure. This raises the risk of myelosuppression, neurotoxicity and constipation or ileus.
How serious is the interaction between Saquinavir and Vinblastine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible or reduce the vinblastine dose, and monitor blood counts and neurological and bowel function. Consider an antiretroviral with less CYP3A4 inhibition.
What other medicines interact with Vinblastine?
MediHelp also lists interactions of Vinblastine with, for example, Adenovirus types 4 and 7 live, Apalutamide, Atazanavir. The full list is on the Vinblastine page.
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