The medications which cranberry juice interferes with are Warfarin also known as Coumadin and Jantoven, blood pressure medications, cholesterol medications, antibiotics and NSAIDs and even Tacrolimus which is an immunosuppressant.
Cranberry juice including cranberry extracts can interfere with tacrolimus by potentially inhibiting intestinal CYP3A enzymes, which can lead to an increase in serum tacrolimus levels.
All reported interactions with cranberry and CYP3A indicate increase of serum levels by this inhibition.
The most well known interaction with cranberry juice and cranberries, is the interaction with Warfarin, Coumadin and Jantoven, which can increase Warfarin's anticoagulant effect and increase risk of bleeding.
Cranberry juice and cranberries can interact with some blood pressure medications like nifedipine, "Procardia", which increases side effects and effects.
Cranberry and Cranberry juice can also interfere with cholesterol medications like Lipitor also known as Atorvastatin.
And there's also potential interactions with NSAIDS and some antibiotics when you consume cranberries and cranberry juice, so you have to be careful when taking these medications and drinking cranberry juice and eating cranberries.
The reason for these interactions with cranberries, cranberry juice and medications is because cranberry contains compounds, which can affect how your liver breaks down certain drugs, like through your CYP2C9 enzyme, which potentially can lead to higher drug levels in the body and an increased risk of side effects.