<unk>  interacts with many commonly used drugs, and the metabolism of<unk>  varies greatly between patients. Some foods have also been reported to interact with<unk> . Apart from the metabolic interactions, highly protein bound drugs can displace<unk>  from serum albumin and cause an increase in the INR. This makes finding the correct dosage difficult, and accentuates the need of monitoring; when initiating a medication that is known to interact with<unk>  (e.g., simvastatin), INR checks are increased or dosages adjusted until a new ideal dosage is found. When taken with nonsteroidal anti-inflammatory drugs (NSAIDs),<unk>  increases the risk for gastrointestinal bleeding. This increased risk is due to the anti-platelet effect of NSAIDs as well as the possible damage to the gastrointestinal mucosa. Many commonly used antibiotics, such as metronidazole or the macrolides, will greatly increase the effect of<unk>  by reducing the metabolism of<unk>  in the body. Other broad-spectrum antibiotics can reduce the amount of the normal bacterial flora in the bowel, which make significant quantities of vitamin K1, thus potentiating the effect of<unk> . In addition, food that contains large quantities of vitamin K1 will reduce the<unk>  effect. Thyroid activity also appears to influence<unk>  dosing requirements; hypothyroidism (decreased thyroid function) makes people less responsive to<unk>  treatment, while hyperthyroidism (overactive thyroid) boosts the anticoagulant effect. Several mechanisms have been proposed for this effect, including changes in the rate of breakdown of clotting factors and changes in the metabolism of<unk> . Excessive use of alcohol is also known to affect the metabolism of<unk>  and can elevate the INR and thus increase the risk of bleeding. The U.S. Food and Drug Administration (FDA) product insert on<unk>  states that alcohol should be avoided. The Cleveland Clinic suggests that when taking<unk>  one should not drink more than "one beer, 6 oz of wine, or one shot of alcohol per day".<unk>  also interacts with many herbs and spices, some used in food (such as ginger and garlic) and others used purely for medicinal purposes (such as ginseng and Ginkgo biloba). All may increase bleeding and bruising in people taking<unk> ; similar effects have been reported with borage (starflower) oil. St. John's Wort, sometimes recommended to help with mild to moderate depression, reduces the effectiveness of a given dose of<unk> ; it induces the enzymes that break down<unk>  in the body, causing a reduced anticoagulant effect. Between 2003 and 2004, the UK Committee on Safety of Medicines received several reports of increased INR and risk of haemorrhage in people taking<unk>  and cranberry juice. Data establishing a causal relationship is still lacking, and a 2006 review found no cases of this interaction reported to the FDA; nevertheless, several authors have recommended that both doctors and patients be made aware of its possibility. The mechanism behind the interaction is still unclear.
Warfarin
Palladin
Clopidogrel
Ticlopidine
Apixaban
Ticagrelor
Heparin
Dabigatran