Drug interactions
Posaconazole + Saquinavir
Severity: Major
Posaconazole and Saquinavir: major interaction.
Last updated Sources: US FDA label
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
Posaconazole can raise saquinavir concentrations, and both drugs can prolong the QT and PR intervals. This increases the risk of serious arrhythmia, particularly with ritonavir-boosted saquinavir.
What this interaction means in plain words
Posaconazole and Saquinavir 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
Posaconazole inhibits CYP3A4 metabolism of saquinavir, with additive QT prolongation.
What to do
Obtain a baseline ECG and monitor it during coadministration, correct electrolyte disturbances, and avoid the combination in patients with QT prolongation or other risk factors.
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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References
Other interactions of Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Frequently asked questions
Can I take Posaconazole with Saquinavir?
MediHelp rates the interaction as major. Posaconazole and Saquinavir 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. Posaconazole can raise saquinavir concentrations, and both drugs can prolong the QT and PR intervals. This increases the risk of serious arrhythmia, particularly with ritonavir-boosted saquinavir.
How serious is the interaction between Posaconazole and Saquinavir?
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 it during coadministration, correct electrolyte disturbances, and avoid the combination in patients with QT prolongation or other risk factors.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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