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Dabrafenib

(duh-braf-uh-nib)

Trade/other name(s): Tafinlar

Why would this drug be used?

This drug is used to treat advanced melanomas that have a certain mutation (change) in the BRAF gene. It is also being studied for use against other types of cancers.

How does this drug work?

Dabrafenib 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. Dabrafenib 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. This drug should not be used in people whose cancers do not have this mutation, as it might actually help these cancers grow.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have diabetes. This drug can raise blood glucose (sugar) levels, which might require an increase in the medicines you take for your diabetes (see “Precautions”).
  • If you have any type of liver disease (including hepatitis) or kidney disease. This drug is cleared from the body by the liver and kidneys. If these organs aren’t working well, your doctor might need to watch you more closely during treatment.
  • If you have glucose-6-phosphate dehydrogenase (G6PD) deficiency. This drug might increase your risk of hemolytic anemia (see “Precautions”).
  • If you have any other medical conditions such as bleeding problems, high blood pressure, heart disease, congestive heart failure, gout, or infections. Your doctor may need to monitor you more closely during treatment.
  • 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 can cause problems with the fetus if taken at the time of conception or during pregnancy. Women who could become pregnant need to follow special precautions if taking this drug (see “Precautions” below).
  • If you are breastfeeding. Although no studies have been done, this drug may pass into breast milk and affect the baby. Breastfeeding is not recommended during treatment with this drug.
  • If you think you might want to have children in the future. This drug might affect fertility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines or supplements you are taking, including vitamins and herbs. In fact, keeping a written list of these (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

Dabrafenib 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 dabrafenib 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 dabrafenib to build up in your blood, which might worsen side effects and other problems:

  • Some antibiotics, such as erythromycin, clarithromycin (Biaxin), telithromycin (Ketek), and similar drugs
  • Anti-fungal medicines such as ketoconazole (Nizoral), itraconazole (Sporanox), 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
  • Gemfibrozil (Lopid), a drug used to lower blood cholesterol and triglyceride (fat) levels

If you take any of these drugs, your doctor might need to switch you to a different drug. If you can’t be switched to a different drug, your doctor will need to watch you closely and might need to adjust your dose of dabrafenib. Do not start or stop taking any of these medicines while on dabrafenib without talking with the prescribing doctor(s) about all of the medicines you take, including dabrafenib.

Many drugs used to treat heartburn, reflux, or ulcers can reduce the acid levels in the stomach, which might affect the amount of dabrafenib your body can absorb. Be sure your doctor knows if you are taking any of these drugs:

  • H2 blockers such as cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), or nizatidine (Axid)
  • Proton pump inhibitors such as omeprazole (Prilosec), esomeprazole (Nexium), pantoprazole (Protonix), rabeprazole (AcipHex), lansoprazole (Prevacid), or dexlansoprazole (Dexilant)
  • Antacids such as Maalox, Mylanta, Tums, etc.

Dabrafenib might lower blood levels of some other drugs in the body, which could make them less effective. Your doctor might need to switch you to a different drug while you are getting dabrafenib, if possible, or might need to watch you closely. Some examples include:

  • The blood-thinning medicine warfarin (Coumadin)
  • Oral contraceptives (birth control pills)
  • The steroid drug dexamethasone (Decadron)
  • Anti-anxiety and sedative drugs called benzodiazepines, such as alprazolam (Xanax), midazolam (Versed), and triazolam (Halcion)
  • Some calcium channel blockers such as amlodipine (Norvasc), diltiazem (Cardizem), verapamil (Calan), and nifedipine (Adalat, Procardia)
  • Some cholesterol-lowering drugs such as simvastatin (Zocor), lovastatin (Mevacor), and atorvastatin (Lipitor)

Other medicines or supplements may affect blood levels of dabrafenib, or levels of these drugs may be affected by taking dabrafenib. 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, grapefruit juice, or grapefruit extract might change the amount of dabrafenib 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?

Dabrafenib is taken by mouth as capsules. The usual starting dose is 150 mg (milligrams), taken twice a day. The capsules should be taken in the morning and in the evening, about 12 hours apart. They should be swallowed whole (not opened, chewed, or crushed). They should be taken at least 1 hour before or at least 2 hours after a meal. Your dose may need to be adjusted or delayed 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 can 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.

This drug can cause fever in some people when it is given. Severe fever reactions are rare but can be dangerous, and can occur along with shaking chills, low blood pressure, feeling dizzy, having too little fluid in the body (dehydration), and kidney problems (including kidney failure). Tell your doctor or nurse right away if you notice fever or any of these other symptoms while taking the drug.

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 might 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 dabrafenib and every 2 months during and for up to 6 months after treatment.

This drug might raise your blood glucose (sugar) level. If you have diabetes or previous problems with high blood sugar, your doctor will check your blood sugar levels before and during treatment. Tell your doctor or nurse if you have symptoms that might be related to high blood sugar levels, such as being thirsty, urinating more often than normal, or having fruity smelling breath. Some people with diabetes taking this drug needed to take more medicine to control their blood sugar.

In people who have glucose-6-phosphate dehydrogenase (G6PD) deficiency, this drug might cause hemolytic anemia. This is a serious condition in which red blood cells are destroyed and removed from the body. Tell your doctor or nurse right away if you have possible symptoms of hemolytic anemia, such as fatigue, shortness of breath, dizziness, headache, coldness in your hands and feet, pale skin, chest pain, or a yellow color in the eyes or skin (jaundice).

This drug may cause eye problems in some people. Your doctor should examine your eyes before and during treatment with this drug. 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 can cause a condition known as hand-foot syndrome, in which a person may have pain, numbness, tingling, redness, or swelling in the hands or feet. If severe, this can cause peeling, blistering, or open sores on the skin in these areas. Let your doctor know right away if you notice any of these symptoms.

Women should avoid pregnancy while taking this drug and for at least 4 weeks after stopping it. This drug can cause problems with the fetus if taken at the time of conception or during pregnancy. Birth control methods that rely on hormones (such as birth control pills, injections, or patches) might not work as well while you are taking this drug, so you need to use another type of effective birth control. Check with your doctor about what kinds of birth control can be used with this medicine. Tell your doctor right away if you become pregnant.

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

  • Thickening of the skin
  • Headache
  • Fever*
  • Joint pain
  • Non-cancerous skin tumors (warts)
  • Hair loss
  • Hand-foot syndrome*
  • High blood sugar level*

Less common

  • Rash
  • Back pain
  • Muscle pain
  • Cough
  • Constipation
  • Swelling in the throat and nasal passages, which can cause a runny nose, stuffy nose, and sore throat
  • Squamous cell skin cancer*
  • Changes in mineral levels in the blood (Your doctor will discuss the importance of this finding, if any.)

Rare

  • Severe fever, sometimes with chills, low blood pressure, dehydration, or kidney failure*
  • Eye problems*
  • New melanomas*
  • Swelling of the pancreas
  • Kidney damage

*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 2013

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: 06/12/2013
Last Revised: 06/12/2013