About This Drug
Cobimetinib is used to treat cancer. It is given orally.
Possible Side Effects (More Common)
- Loose bowel movements (diarrhea) that may last for a few days.
- Electrolyte changes. Your blood will be checked for electrolyte changes as needed.
- Sensitivity to light (photosensitivity). Photosensitivity means that you may become more sensitive to the sun, sun lamps, and tanning beds. Your eyes may water more, mostly in bright light.
- Nausea and throwing up (vomiting). These symptoms may happen within a few hours after your treatment and may last up to 24 hours. Medicines are available to stop or lessen these side effects.
- Rash: A rash that looks like acne may happen on your face and upper back when taking this medicine. Your doctor can give you medicine to help treat this.
- Bone marrow depression. This is a decrease in the number of white blood cells, red blood cells, and platelets. This may raise your risk of infection, make you tired and weak (fatigue), and raise your risk of bleeding.
- Changes in your liver function. Your doctor will check your liver function as needed.
- This drug may affect how your kidneys work. Your doctor will check your kidney function as needed.
- Elevation of substance in your blood called creatinine phosphokinase. Your doctor will check your blood as needed.
Possible Side Effects (Less Common)
- Changes in the tissue of the heart. Some changes may happen that can cause your heart to have less ability to pump blood. Your heart function will be checked as needed.
- Soreness of the mouth and throat. You may have red areas, white patches, or sores that hurt.
- This drug may raise your risk of getting a second cancer.
- High blood pressure. Your doctor will check your blood pressure as needed.
- Blurred vision or other changes in eyesight.
Treating Side Effects
- Drink 6-8 cups of fluids each day unless your doctor has told you to limit your fluid intake due to some other health problem. A cup is 8 ounces of fluid. If you throw up or have loose bowel movements, you should drink more fluids so that you do not become dehydrated (lack water in the body from losing too much fluid).
- Ask your doctor or nurse about medicine that is available to help stop or lessen the loose bowel movements.
- Wear dark sun glasses when in the sun or bright lights.
- Mouth care is very important. Your mouth care should consist of routine, gentle cleaning of your teeth or dentures and rinsing your mouth with a mixture of 1/2 teaspoon of salt in 8 ounces of water or ½ teaspoon of baking soda in 8 ounces of water. This should be done at least after each meal and at bedtime.
- If you have mouth sores, avoid mouthwash that has alcohol. Also avoid alcohol and smoking because they can bother your mouth and throat.
- If you get a rash do not put anything on it unless your doctor or nurse says you may. Keep the area around the rash clean and dry. Ask your doctor for medicine if your rash bothers you.
- Swallow the medicine whole. Do not chew, break or crush it.
- Take this medicine at the same time each day
Food and Drug Interactions
There are no known interactions of cobimetinib with food. This drug may interact with other medications. Tell your doctor and pharmacist about all the medication and dietary supplements (vitamins, minerals, herbs, and others) that you are currently taking. The safety and effectiveness of dietary supplements and alternative diets are often unknown. Using these might unexpectedly affect your cancer or interfere with your treatment. Until more is known, you should not use dietary supplements or alternative diets without your cancer doctor's help.
When to Call the Doctor
Call your doctor or nurse immediately if you have any of the following symptoms:
- Fever of 100.5 F (38 C) or higher
- Easy bleeding or bruising
- Wheezing or trouble breathing
- Rash or itching
- Feeling dizzy or lightheaded
- Loose bowel movements (diarrhea) more than 4 times a day or diarrhea with weakness or lightheadedness
- Blurred vision or other changes in eyesight
- Pain when passing urine; blood in urine
- Pain in your lower back or side
- Confusion or agitation
- Nausea that stops you from eating or drinking
- Throwing up more than 3 times a day
- Chest pain or symptoms of a heart attack. Most heart attacks involve pain in the center of the chest that lasts more than a few minutes. The pain may go away and come back. It can feel like pressure, squeezing, fullness, or pain. Sometimes pain is felt in one or both arms, the back, neck, jaw, or stomach. If any of these symptoms last 2 minutes, call 911.
- Symptoms of a stroke such as sudden numbness or weakness of your face, arm, or leg, mostly on one side of your body; sudden confusion, trouble speaking or understanding; sudden trouble seeing in one or both eyes; sudden trouble walking, feeling dizzy, loss of balance or coordination; or sudden, bad headache with no known cause. If you have any of these symptoms for 2 minutes, call 911.
- Signs of liver problems: dark urine, pale bowel movements, bad stomach pain, feeling very tired and weak, unusual itching, or yellowing of the eyes or skin.
Call your doctor or nurse as soon as possible if any of the following symptoms occur:
- Change in hearing, ringing in the ears
- Decreased urine
- Unusual thirst or passing urine often
- Pain in your mouth or throat that makes it hard to eat or drink
- Nausea that is not relieved by prescribed medicines
- Rash that is not relieved by prescribed medicines
- Heavy menstrual period that lasts longer than normal
- Swelling of legs, ankles, or feet
- Weight gain of 5 pounds in one week (fluid retention)
- Lasting loss of appetite or rapid weight loss of five pounds in a week
- Fatigue that interferes with your daily activities
- Headache that does not go away
- No bowel movement for 3 days or you feel uncomfortable
- Extreme weakness that interferes with normal activities
- Infertility warning: Sexual problems and reproduction concerns may happen. In men and women both, this drug may affect your ability to have children. This cannot be determined before your therapy. Talk with your doctor or nurse if you plan to have children. Ask for information on sperm or egg banking.
- Pregnancy warning: This drug may have harmful effects on the unborn baby, so effective methods of birth control should be used by women during your cancer treatment and for at least 2 weeks after treatment. Genetic counseling is available for you to talk about the effects of this drug therapy on future pregnancies. Also, a genetic counselor can look at the possible risk of problems in the unborn baby due to this medicine if an exposure happens during pregnancy.
- Breast feeding warning: It is not known if this drug passes into breast milk. For this reason, it is recommended that women do not breast feed during treatment or for 2 weeks after the final dose because this drug may enter the breast milk and cause harm to a breast feeding baby.
Updated January 2017