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Cobimetinib (By mouth)

Cobimetinib (koe-bi-ME-ti-nib)

Treats melanoma (skin cancer).

Brand Name(s):


There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you had an allergic reaction to cobimetinib, or if you are pregnant or breastfeeding.

How to Use This Medicine:


  • Medicines used to treat cancer are very strong and can have many side effects. Before receiving this medicine, make sure you understand all the risks and benefits. It is important for you to work closely with your doctor during your treatment.
  • Your doctor will tell you how much medicine to use. Do not use more than directed.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
  • Missed dose: If you vomit after taking a dose or miss a dose, take your next regular dose at the next scheduled time. Do not take extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some foods and medicines can affect how cobimetinib works. Tell your doctor if you are using carbamazepine, ciprofloxacin, efavirenz, erythromycin, itraconazole, phenytoin, rifampin, or St John's wort.

Warnings While Using This Medicine:

  • It is not safe to take this medicine during pregnancy. It could harm an unborn baby. Tell your doctor right away if you become pregnant. Use birth control during treatment and for 2 weeks after your last dose.
  • Do not breastfeed while you are taking this medicine and for 2 weeks after your last dose.
  • Tell your doctor if you have liver disease, bleeding problems, heart disease, or other skin problems.
  • Tell your doctor if you have the following problems:
    • High risk of other skin cancer
    • High risk of bleeding
    • Heart disease
    • Serious skin reactions
    • Fluid accumulation in the eye and similar eye problems
    • Liver problems
    • Rhabdomyolysis (severe muscle problem)
  • This medicine could cause infertility in men or women. Talk with your doctor before using this medicine if you plan to have children.
  • This medicine may make your skin more sensitive to sunlight. Wear sunscreen. Do not use sunlamps or tanning beds.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blurred vision, vision changes, eye pain
  • Change in size or color of a mole, new wart, a sore or reddish bump that bleeds or does not heal
  • Chest pain, fast or uneven heartbeat, trouble breathing, persistent coughing or wheezing
  • Dark urine or pale stools, nausea, vomiting, loss of appetite, stomach pain, yellow skin or eyes
  • Muscle pain, tenderness, or weakness
  • Red or black stools, red or dark brown urine, headache, dizziness, or unusual vaginal bleeding
  • Severe rash, painful itchy skin that is hot to the touch, or thickened dry wrinkled skin
  • Swelling in your hands, ankles or feet

If you notice these less serious side effects, talk with your doctor:

  • Diarrhea
  • Sensitivity of the skin to sunlight

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 3/19/2020

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