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Vemurafenib

(vem-yoo-raf-uh-nib)

Trade/other name(s): Zelboraf

Why would this drug be used?

This drug is used to treat advanced melanomas that have a certain mutation in the BRAF gene.

How does this drug work?

Vemurafenib is a type of targeted therapy known as a kinase inhibitor. Kinases are proteins on or near the surface of a cell that transmit important signals to the cell's control center. When the BRAF gene is mutated, it makes a kinase that tells the cell to grow and divide in an out of control way. Vemurafenib blocks the mutated form of the BRAF kinase, as well as some other kinases.

About half of all melanomas have the mutated BRAF gene. Your doctor will test your cancer cells to be sure they have this mutation before starting treatment with this drug.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any type of liver disease (including hepatitis). This drug may affect the liver. If this happens, your doctor may need to adjust your dose.
  • If you have ever been diagnosed with heart problems, especially long QT syndrome or an abnormal heart rhythm, or if you have been told you have low blood levels of potassium, calcium, or magnesium (which can affect the heart). See “Precautions” section. People with long QT syndrome or low blood levels of these minerals should not take this drug.
  • If you have any other medical conditions such as bleeding problems, kidney disease, congestive heart failure, diabetes, gout, or infections. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you plan to have surgery or any medical or dental procedures in the near future.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug may cause problems with the fetus if the man or woman is taking at the time of conception or if a woman takes it during pregnancy. See “Precautions” section.
  • If you are breast-feeding. Although no studies have been done, this drug may pass into breast milk and affect the baby. Breast-feeding is not recommended during treatment with this drug.
  • If you think you might want to have children in the future. It is not known if this drug affects fertility. Talk with your doctor about the possible risk with this drug.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Vemurafenib can interact with a number of drugs and supplements, so it is important to check with your health care team before taking any new medicines.

The following drugs and supplements can lower the levels of vemurafenib in the blood and might make it less effective:

  • Anti-seizure drugs, such as carbamazepine (Tegretol), phenobarbital (Solfoton), and phenytoin (Dilantin)
  • Drugs to treat tuberculosis (TB), such as rifampin (Rifadin, Rimactane; also in Rifamate and Rifater), rifabutin (Mycobutin), and rifapentine (Prifin)
  • The steroid drug dexamethasone (Decadron)
  • St. John's wort (herbal dietary supplement)

Some drugs and supplements could cause vemurafenib to build up in your blood, which might worsen side effects and other problems:

  • Some antibiotics, such as erythromycin, clarithromycin (Biaxin), telithromycin (Ketek), and drugs like them
  • Anti-fungal medicines such as ketoconazole (Nizoral), itraconazole (Sporanox), fluconazole (Diflucan), and voriconazole (Vfend)
  • Some anti-depressant drugs, such as nefazodone (Serzone)
  • Anti-HIV drugs such as indinavir (Crixivan), ritonavir (Kaletra), nelfinavir (Viracept), atazanavir (Reyataz), saquinavir (Invirase), and others

If you need to take any of these drugs, your doctor may need to adjust your dose of vemurafenib. Do not start or stop taking any of these medicines while on vemurafenib without talking with the prescribing doctor(s) about all of the medicines you take, including vemurafenib.

Be sure to tell your doctor if you are taking the blood-thinning medicine warfarin (Coumadin). Vemurafenib may raise your blood levels of this drug. You may need blood tests to monitor how well this drug is working, and/or your dose of warfarin may need to be lowered while you are getting vemurafenib.

Because vemurafenib may affect the rhythm of your heart, be sure your doctor is aware of any drugs you take that affect heart rhythm, such as amiodarone (Cordarone), disopyramide (Norpace), dofetilide (Tikosyn), flecainide (Tambocor), mexiletine (Mexitil), moricizine (Ethmozine), procainamide (Procanbid, Pronestyl), propafenone (Rythmol), quinidine (Quinidex), sotalol (Betapace), and tocainide (Tonocard).

If you’re taking the drug ipilimumab (Yervoy) along with this drug, you may have a higher risk of liver damage.

Other medicines or supplements may affect blood levels of vemurafenib, or levels of these drugs may be affected by taking vemurafenib. Make sure your doctor is aware of all drugs and supplements you are taking.

Check with your doctor, nurse, or pharmacist about any other medicines, herbs, and supplements you are taking, and whether alcohol can cause problems with this medicine.

Interactions with foods

Grapefruit and grapefruit juice may affect the amount of vemurafenib in the body. Check with your doctor, nurse, or pharmacist about whether you should avoid these, and whether any other specific foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Vemurafenib is taken by mouth as tablets. The usual starting dose is 960 mg (milligrams) taken as four 240 mg tablets, twice a day. The tablets should be taken in the morning and in the evening, about 12 hours apart. They should be swallowed whole (not chewed or crushed) with a glass of water. They can be taken with or without food. Your dose may need to be adjusted if you have side effects.

Take this drug exactly as directed by your doctor. If you do not understand the instructions, ask your doctor or nurse to explain them to you. Keep the medicine in a tightly closed container away from heat and moisture and out of the reach of children and pets.

Precautions

This drug may interact with a number of other drugs or supplements in the body. (See "Interactions" above.) Be sure your doctor is aware of all drugs and supplements you are taking. Do not start or stop taking any drug without talking to your doctor about all of them.

Vemurafenib may affect the heart's rhythm and prolong the QT interval (slow down the electrical impulses in the heart). Tell your doctor if you have ever been diagnosed with heart disease. Your doctor will test your heart rhythm with an EKG and will test your blood levels of certain minerals that could affect heart rhythm before you start treatment and several times during treatment. Report any episodes of fast or irregular heartbeat, chest pain, lightheadedness, dizziness, or shortness of breath to your doctor right away. These changes can be life-threatening.

This drug can cause allergic reactions in some people when it is given. Serious reactions are rare but can be dangerous. Symptoms can include rash or redness of the skin, feeling lightheaded or dizzy, fast heartbeat, chest tightness or pain, trouble breathing or swallowing, hoarseness, flushing, back pain, or swelling of the face, tongue, or throat. Tell your doctor or nurse right away if you notice any of these symptoms after taking the drug.

This drug may rarely cause a fast-spreading rash and blistering or peeling of the skin (usually on the hands), sometimes along with swelling or sores in the mouth. This condition, known as Stevens-Johnson syndrome, can be severe or even life-threatening. Tell your doctor or nurse right away if you notice any new rashes, skin redness, fever, blistering or peeling of the skin, or mouth sores or swelling of the face, hands, or the soles of your feet.

This drug can make your skin very sensitive to sunlight, which could make your skin burn more easily and lead to severe sunburns. You should try to avoid sunlight while taking this drug. When going outdoors, you should wear clothes that protect your skin, including your face, head, hands, arms, and legs, and use broad-spectrum sunscreen and lip balm with an SPF of at least 30.

This drug can increase your risk of another type of skin cancer called squamous cell carcinoma. This type of cancer rarely spreads to other parts of the body and can usually be removed completely with surgery. This drug may also raise your risk of developing another melanoma or other type of skin cancer. Tell your doctor if you notice any skin changes, including new warts, skin sores or reddish bumps that do not heal, or a change in size or color of a mole. Your doctor should check your skin before you start taking vemurafenib and every 2 months during and for up to 6 months after treatment.

This drug may cause eye problems in some people. Tell your doctor or nurse if you have eye pain, swelling, or redness or if you notice any changes in vision while taking this drug.

This drug may cause liver damage. Your doctor will order blood tests and will check you for signs of liver problems before and during treatment to make sure your liver is working well. Tell your doctor or nurse right away if you have yellowing of the skin or the whites of your eyes (jaundice), dark urine, nausea or vomiting, loss of appetite, pain on the right side of your belly, or any abnormal bruising or bleeding.

Avoid pregnancy while taking this drug and for at least 2 months afterward. It may harm the fetus. Both men and women should use effective birth control during treatment and for at least 2 months afterward. Check with your doctor about what kinds of birth control can be used with this medicine. In pregnant women, treatment with this drug should be used only if the potential benefit to the mother outweighs the risk to the fetus.

Possible side effects

You will probably not have most of the following side effects, but if you have any tell your doctor or nurse. They can help you understand the side effects and cope with them.

Common

  • Joint pain
  • Hair loss
  • Rash
  • Skin itching
  • Sensitivity to sunlight*
  • Squamous cell skin cancer*
  • Warts
  • Feeling tired
  • Headache
  • Nausea
  • Diarrhea

Less common

  • Dry skin
  • Redness of the skin*
  • Loss of appetite
  • Vomiting
  • Constipation
  • Muscle pain
  • Back pain
  • Fever
  • Swelling in the hands or feet
  • Weakness
  • Changes in taste
  • Cough
  • Sunburn*
  • Abnormal blood test results, suggesting drug may be affecting the liver (Your doctor will discuss the importance of this finding, if any.)*

Rare

  • Allergic reactions*
  • Severe skin reactions with redness and blistering*
  • Changes in heart rhythm*
  • Eye problems*
  • Other skin cancers*
  • Weight loss
  • Inflammation in veins
  • Numbness or tingling in the hands or feet

*See the "Precautions" section for more detailed information.

Other side effects not listed above can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 2011

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 08/27/2013
Last Revised: 08/27/2013