Drug interactions
Cyclophosphamide + Thiotepa
Severity: Major
Cyclophosphamide 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
Both agents are alkylating drugs that suppress the bone marrow. Combined use, as in high-dose conditioning regimens, increases the risk of severe prolonged cytopenias and infection. Cyclophosphamide may also reduce thiotepa activation or clearance via CYP effects.
What this interaction means in plain words
Cyclophosphamide 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.
Cyclophosphamide belongs to Oncology; Thiotepa belongs to Oncology.
Why it happens
Additive myelosuppression from two alkylating agents, with possible metabolic interplay via CYP2B6 and CYP3A4.
What to do
Monitor blood counts closely and provide supportive care, including growth factors and transfusions as needed. Adjust doses according to established protocols.
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 Cyclophosphamide
Other interactions of Thiotepa
- Bendamustine + Thiotepa Major
- Chlorambucil + Thiotepa Major
- Clarithromycin + Thiotepa Major
- Dacarbazine + Thiotepa Major
- Deferiprone + Thiotepa Major
- Fingolimod + Thiotepa Major
Frequently asked questions
Can I take Cyclophosphamide with Thiotepa?
MediHelp rates the interaction as major. Cyclophosphamide 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. Both agents are alkylating drugs that suppress the bone marrow. Combined use, as in high-dose conditioning regimens, increases the risk of severe prolonged cytopenias and infection. Cyclophosphamide may also reduce thiotepa activation or clearance via CYP effects.
How serious is the interaction between Cyclophosphamide 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: Monitor blood counts closely and provide supportive care, including growth factors and transfusions as needed. Adjust doses according to established protocols.
What other medicines interact with Cyclophosphamide?
MediHelp also lists interactions of Cyclophosphamide with, for example, Adenovirus types 4 and 7 live, Belatacept, Bendamustine. The full list is on the Cyclophosphamide page.
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