Coumadin and Ketoconazole (Systemic)

In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.

Ketoconazole may increase the blood levels of warfarin and cause you to bleed more easily. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Call your doctor immediately if you experience any unusual bleeding or bruising, vomiting, blood in your urine or stools, headache, dizziness, or weakness during treatment with these medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

MONITOR: Azole antifungal agents that are potent inhibitors of CYP450 3A4 such as itraconazole, ketoconazole, and posaconazole may increase the plasma concentrations and hypoprothrombinemic effect of warfarin. The proposed mechanism is inhibition of CYP450 3A4-mediated metabolism of R(+) warfarin, the less biologically active of the two enantiomers of warfarin. There have been isolated case reports of patients stabilized on warfarin who developed bleeding complications, bruising, and/or significantly increased prothrombin time (PT) or INR following the addition of itraconazole or ketoconazole therapy. Interruption and/or reduction in warfarin dosing were required.

MANAGEMENT: Patients receiving warfarin should be closely monitored during concomitant therapy with azole antifungal agents that are potent inhibitors of CYP450 3A4. The INR should be checked frequently and warfarin dosage adjusted accordingly, particularly following initiation, change of dosage, or discontinuation of azole antifungal therapy. The same precaution may be applicable during therapy with other coumarin anticoagulants, although clinical data are lacking. Patients should be advised to promptly report any signs of bleeding to their physician, including pain, swelling, headache, dizziness, weakness, prolonged bleeding from cuts, increased menstrual flow, vaginal bleeding, nosebleeds, bleeding of gums from brushing, unusual bleeding or bruising, red or brown urine, or red or black stools.

Coumadin

Generic Name: warfarin

Brand name: Coumadin, Jantoven

Synonyms: n.a.

What is Coumadin?

Ketoconazole (Systemic)

Generic Name: ketoconazole

Brand name: Nizoral

Synonyms: Ketoconazole

What is Ketoconazole (Systemic)?