Coumadin and Seroquel

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.

QUEtiapine may occasionally increase the effects of warfarin in some patients. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring of your INR to safely use both medications. You should seek immediate medical attention if you experience any unusual bleeding or bruising, or have other signs and symptoms of bleeding such as dizziness; lightheadedness; red or black, tarry stools; coughing up or vomiting fresh or dried blood that looks like coffee grounds; severe headache; and weakness. 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: Limited data suggest that quetiapine may potentiate the hypoprothrombinemic effects of warfarin. The mechanism of interaction has not been established. According to the product labeling, quetiapine did not affect the binding of warfarin to human serum albumin in vitro. Additionally, in vitro enzyme inhibition data suggest that quetiapine and its metabolites would have little inhibitory effect on in vivo metabolism mediated by CYP450 1A2, 2C9, 2C19, 2D6 and 3A4, thus no clinically relevant pharmacokinetic interactions are expected of quetiapine on other drugs based on these pathways. A pharmacokinetic study between quetiapine and warfarin has not been conducted. Nonetheless, there have been isolated case reports in the medical literature describing a potential interaction between quetiapine and warfarin in elderly patients resulting in significantly increased INRs and/or bleeding complications, including gastrointestinal hemorrhage and multiple intracerebral hemorrhages in two separate cases.

MANAGEMENT: Until more data are available, caution may be advisable if quetiapine is used in combination with warfarin. The INR should be checked frequently and warfarin dosage adjusted accordingly, particularly following initiation, discontinuation or change of dosage of quetiapine in patients who are stabilized on their warfarin regimen. The same precaution may be applicable during therapy with other similar anticoagulants, although clinical data are lacking. Patients should be advised to promptly report any signs of bleeding to their doctor, 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?

Seroquel

Generic Name: quetiapine

Brand name: Seroquel, Seroquel XR

Synonyms: n.a.

What is Seroquel?