Drug interactions
Dalteparin + Fosphenytoin
Severity: Minor
Dalteparin and Fosphenytoin: minor 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
Phenytoin and its prodrug fosphenytoin alter the response to oral anticoagulants, but a clinically important interaction with dalteparin is not established. The legacy claim that dalteparin raises fosphenytoin levels is unsupported.
What this interaction means in plain words
Dalteparin and Fosphenytoin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Dalteparin belongs to Cardiovascular; Fosphenytoin belongs to Central Nervous System.
Why it happens
No established mechanism for LMWH; the enzyme induction and protein binding effects of phenytoin chiefly concern vitamin K antagonists.
What to do
No dose change is routinely needed. Monitor for bleeding and check phenytoin levels if toxicity or loss of seizure control is suspected.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Dalteparin and Fosphenytoin, 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 Dalteparin
- Dalteparin + Defibrotide Contraindicated
- Dalteparin + Ketorolac Contraindicated
- Dalteparin + Mifepristone Contraindicated
- Abciximab + Dalteparin Major
- Acalabrutinib + Dalteparin Major
- Aceclofenac + Dalteparin Major
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Dalteparin with Fosphenytoin?
MediHelp rates the interaction as minor. Dalteparin and Fosphenytoin have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Phenytoin and its prodrug fosphenytoin alter the response to oral anticoagulants, but a clinically important interaction with dalteparin is not established. The legacy claim that dalteparin raises fosphenytoin levels is unsupported.
How serious is the interaction between Dalteparin and Fosphenytoin?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No dose change is routinely needed. Monitor for bleeding and check phenytoin levels if toxicity or loss of seizure control is suspected.
What other medicines interact with Dalteparin?
MediHelp also lists interactions of Dalteparin with, for example, Defibrotide, Ketorolac, Mifepristone. The full list is on the Dalteparin 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.
