Drug Interactions between dicumarol and selumetinib

Grapefruit juice can increase the blood levels of selumetinib. This may increase the risk and/or severity of serious side effects such as diarrhea; colitis (inflammation of the colon); skin rashes; cardiomyopathy (a condition that affects the heart muscle and its ability to pump blood); rhabdomyolysis (a rare condition involving the breakdown of skeletal muscle tissue that can cause kidney damage and death); and eye problems that can lead to blindness. Do not consume grapefruit, grapefruit juice, or any supplements that contain grapefruit extract during treatment with selumetinib. Talk to your doctor or pharmacist if you have any questions or concerns. You should seek prompt medical attention if you experience severe diarrhea; severe skin reactions (rash over a large area of the body, peeling skin, blisters); signs and symptoms of heart trouble (persistent coughing or wheezing, shortness of breath, swelling of ankles and feet, fatigue, increased heart rate); muscle problems (unexplained muscle pain, tenderness or weakness, especially with fever and/or dark colored urine); or vision problems (blurred vision, light sensitivity, dark spots or floaters, vision loss). 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.

Nutrition and diet can affect your treatment with dicumarol. Therefore, it is important to keep your vitamin supplement and food intake steady throughout treatment. For example, increasing vitamin K levels in the body can promote clotting and reduce the effectiveness of dicumarol. While there is no need to avoid products that contain vitamin K, you should maintain a consistent level of consumption of these products. Foods rich in vitamin K include beef liver, broccoli, Brussels sprouts, cabbage, collard greens, endive, kale, lettuce, mustard greens, parsley, soy beans, spinach, Swiss chard, turnip greens, watercress, and other green leafy vegetables. Moderate to high levels of vitamin K are also found in other foods such as asparagus, avocados, dill pickles, green peas, green tea, canola oil, margarine, mayonnaise, olive oil, and soybean oil. However, even foods that do not contain much vitamin K may occasionally affect the action of dicumarol. There have been reports of patients who experienced bleeding complications and increased INR or bleeding times after consuming large quantities of cranberry juice, mangos, grapefruit, grapefruit juice, grapefruit seed extract, or pomegranate juice. Again, you do not need to avoid these foods completely, but it may be preferable to limit their consumption, or at least maintain the same level of use while you are receiving dicumarol. Talk to a healthcare provider if you are uncertain about what foods or medications you take that may interact with dicumarol. It is important to tell your doctor about all medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

When dicumarol is given with enteral (tube) feedings, you may interrupt the feeding for one hour before and one hour after the dicumarol dose to minimize potential for interaction. Feeding formulas containing soy protein should be avoided.