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Drug interactions between Coumadin and Dilantin

Results for the following 2 drugs:
Coumadin (warfarin)
Dilantin (phenytoin)

Interactions between your selected drugs


warfarin ↔ phenytoin

Applies to:Coumadin (warfarin) and Dilantin (phenytoin)

Using warfarin together with phenytoin may cause you to bleed more easily. It may also increase phenytoin levels. Phenytoin levels and prothrombin time or International Normalized Ratio (INR) should be monitored whenever the dosage is changed or discontinued. You should notify your doctor promptly if you have any signs of unusual or prolonged bleeding, bruising, vomiting, or change in stool or urine color. Also if you have signs of phenytoin toxicity such as drowsiness, visual problems, change in mental status, or seizures. It is important that you tell your healthcare provider about all other medications that you are using including vitamins and herbs. Do not stop using your medications without first talking to your doctor first.

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Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.

Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.

Do not stop taking any medications without consulting your healthcare provider.

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