Drug interactions
Ritonavir + Thiotepa
Severity: Major
Ritonavir and Thiotepa: 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
Ritonavir strongly inhibits CYP3A4 and may alter thiotepa activation and clearance. This can increase toxicity, notably bone marrow suppression, or change efficacy.
What this interaction means in plain words
Ritonavir and Thiotepa 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.
Ritonavir belongs to Anti Virals; Thiotepa belongs to Oncology.
Why it happens
Strong CYP3A4 inhibition by ritonavir alters thiotepa metabolism.
What to do
Avoid concurrent use where possible, for example by choosing a boosting-free antiretroviral regimen. If unavoidable, monitor closely for toxicity and blood counts.
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 Thiotepa
- Bendamustine + Thiotepa Major
- Chlorambucil + Thiotepa Major
- Clarithromycin + Thiotepa Major
- Cyclophosphamide + Thiotepa Major
- Dacarbazine + Thiotepa Major
- Deferiprone + Thiotepa Major
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Ritonavir with Thiotepa?
MediHelp rates the interaction as major. Ritonavir and Thiotepa 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. Ritonavir strongly inhibits CYP3A4 and may alter thiotepa activation and clearance. This can increase toxicity, notably bone marrow suppression, or change efficacy.
How serious is the interaction between Ritonavir and Thiotepa?
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 concurrent use where possible, for example by choosing a boosting-free antiretroviral regimen. If unavoidable, monitor closely for toxicity and blood counts.
What other medicines interact with Thiotepa?
MediHelp also lists interactions of Thiotepa with, for example, Bendamustine, Chlorambucil, Clarithromycin. The full list is on the Thiotepa page.
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