Drug interactions
Perphenazine + Saquinavir
Severity: Major
Perphenazine and Saquinavir: 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 can prolong the QT and PR intervals, and perphenazine adds QT risk, increasing the likelihood of torsades de pointes. Saquinavir also inhibits CYP3A4 and may raise perphenazine exposure.
What this interaction means in plain words
Perphenazine 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
Additive QT prolongation, with CYP3A4 inhibition by saquinavir raising perphenazine levels.
What to do
Avoid the combination where possible, and use an alternative antipsychotic or antiretroviral. If both are required, obtain a baseline ECG, correct electrolytes, and monitor the QTc.
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 Perphenazine
- Ibutilide + Perphenazine Contraindicated
- Perphenazine + Pimozide Contraindicated
- Perphenazine + Thioridazine Contraindicated
- Adagrasib + Perphenazine Major
- Alfentanil + Perphenazine Major
- Amiodarone + Perphenazine Major
Frequently asked questions
Can I take Perphenazine with Saquinavir?
MediHelp rates the interaction as major. Perphenazine 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. Saquinavir can prolong the QT and PR intervals, and perphenazine adds QT risk, increasing the likelihood of torsades de pointes. Saquinavir also inhibits CYP3A4 and may raise perphenazine exposure.
How serious is the interaction between Perphenazine 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: Avoid the combination where possible, and use an alternative antipsychotic or antiretroviral. If both are required, obtain a baseline ECG, correct electrolytes, and monitor the QTc.
What other medicines interact with Perphenazine?
MediHelp also lists interactions of Perphenazine with, for example, Ibutilide, Pimozide, Thioridazine. The full list is on the Perphenazine page.
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