Drug General Information (ID: DDII1Z3Q0D)
Drug Name			Dicoumarol		Drug Info		Ethotoin		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Anticoagulants				Anticonvulsants
Structure

Mechanism of Dicoumarol-Ethotoin Interaction (Severity Level: Moderate)
Increased risk of bleeding Click to Show/Hide Mechanism Graph
Drug Name		Dicoumarol				Ethotoin
Mechanism		Vitamin K antagonist				Potentiate the hypoprothrombinemic effect of vitamin K antagonist
Key Mechanism Factor 1
		Factor Name		Bleeding
		Factor Description		Patients may be at risk for bleeding when the outcome of a disease or disease treatment confounds the standard mechanisms for maintaining hemostasis. Signs or symptoms of abnormal bleeding include: bleeding that takes a long time to stop (including nosebleeds, bleeding gums, bleeding from cuts and abrasions, and menstrual bleeding); severe unexplained bruising, or bruising that becomes larger; blood in the urine or stool, etc.
Mechanism Description		Increased risk of bleeding by the combination of Dicoumarol and Ethotoin

Recommended Action
Management		Phenytoin serum concentrations and INR/PT should be monitored in patients receiving this combination and whenever the dosage is changed or discontinued. Patients should be advised to promptly report any signs of bleeding (e.g., pain, swelling, headache, dizziness, weakness, prolonged bleeding from cuts, nosebleeds, bleeding of gums from brushing, red or brown urine, or red or black stools) or hydantoin toxicity (e.g., drowsiness, visual disturbances, change in mental status, seizures, nausea, or ataxia) to their physician.

References
1	Koch-Weser J, Sellers EM "Drug interactions with coumarin anticoagulants (first of two parts)." N Engl J Med 285 (1971): 487-98. [PMID: 4397794]
2	Koch-Weser J, Sellers EM "Drug interactions with coumarin anticoagulants (second of two parts)." N Engl J Med 285 (1971): 547-58. [PMID: 4397794]
3	Nappi JM "Warfarin and phenytoin interaction." Ann Intern Med 90 (1979): 852. [PMID: 434697]