Drug interactions
Factor viii + Marstacimab
Severity: Major
Factor viii and Marstacimab: 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
Marstacimab inhibits tissue factor pathway inhibitor and raises hemostatic potential, and adding factor VIII concentrates may further increase the risk of thromboembolic events. Factor VIII used for prophylaxis should be discontinued before starting marstacimab.
What this interaction means in plain words
Factor viii and Marstacimab 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.
Factor viii belongs to Cardiovascular; Marstacimab belongs to Cardiovascular.
Why it happens
Additive procoagulant pharmacodynamic effects of TFPI inhibition and exogenous factor VIII.
What to do
Stop factor VIII prophylaxis before starting marstacimab, and use the lowest effective factor VIII dose only for breakthrough bleeds. Monitor for signs of thrombosis.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Factor viii and Marstacimab, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Factor viii
- Concizumab + Factor viii Major
Frequently asked questions
Can I take Factor viii with Marstacimab?
MediHelp rates the interaction as major. Factor viii and Marstacimab 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. Marstacimab inhibits tissue factor pathway inhibitor and raises hemostatic potential, and adding factor VIII concentrates may further increase the risk of thromboembolic events. Factor VIII used for prophylaxis should be discontinued before starting marstacimab.
How serious is the interaction between Factor viii and Marstacimab?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Stop factor VIII prophylaxis before starting marstacimab, and use the lowest effective factor VIII dose only for breakthrough bleeds. Monitor for signs of thrombosis.
What other medicines interact with Factor viii?
MediHelp also lists interactions of Factor viii with, for example, Concizumab. The full list is on the Factor viii page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
