Vemurafenib is used to treat certain types of melanoma (a type of skin cancer) that cannot be treated with surgery or that has spread to other parts of the body. It is also used to treat a certain type of Erdheim-Chester disease (ECD; a disease that causes an overproduction of a type of white blood cells). Vemurafenib is in a class of medications called kinase inhibitors. It works by blocking the action of an abnormal protein that signals cancer cells to multiply. This helps slow or stop the spread of cancer cells.

Vemurafenib comes as a tablet to take by mouth. It is usually taken with or without food twice a day, in the morning and evening, about 12 hours apart. Take vemurafenib at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take vemurafenib exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor. Do not stop taking vemurafenib without talking to your doctor.

Swallow the tablets whole with a glass of water; do not chew or crush them.

If you vomit after you take vemurafenib, do not immediately take another dose. Continue your regular dosing schedule.

Your doctor may need to temporarily or permanently stop your treatment or decrease your dose of vemurafenib during your treatment.This depends on how well the medication works for you and the side effects you experience. Be sure to tell your doctor how you are feeling during your treatment with vemurafenib.

Your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with vemurafenib and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer’s website to obtain the Medication Guide.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking vemurafenib,

• tell your doctor and pharmacist if you are allergic to vemurafenib, any other medications, or any of the ingredients in vemurafenib tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: certain antifungals such as itraconazole (Onmel, Sporanox), ketoconazole (Nizoral), and voriconazole (Vfend); clarithromycin (Biaxin, in PrevPac); certain medications for human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) such as indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), and saquinavir (Invirase); certain medications for seizures such as carbamazepine (Carbatrol, Epitol, Tegretol, others), phenobarbital, and phenytoin (Dilantin, Phenytek); nefazodone; rifampin (Rifadin, Rimactane, in Rifamate, in Rifater); tizanidine; and warfarin (Coumadin, Jantoven). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with vemurafenib, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
• tell your doctor if you have or have ever had any type of skin cancer; a prolonged QT interval (a rare heart problem that may cause irregular heartbeat, fainting, or sudden death); heart failure; a low level of calcium, magnesium, or potassium in your blood; heart, kidney, or liver disease. Also, tell your doctor if you have had or are planning to receive radiation therapy.
• tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while you are taking vemurafenib. You should use birth control to prevent pregnancy during your treatment with vemurafenib and for 2 weeks after your final dose. Talk to your doctor about birth control methods that will work for you. If you become pregnant while taking vemurafenib, call your doctor. Vemurafenib may harm the fetus.
• tell your doctor if you are breastfeeding. You should not breastfeed while taking vemurafenib and for 2 weeks after your final dose.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking vemurafenib.
• plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, lip balm and sunscreen (SPF 30 or higher). Vemurafenib may make your skin sensitive to sunlight.

Unless your doctor tells you otherwise, continue your normal diet.

Take the missed dose as soon as you remember it. However, if it is within 4 hours of your next scheduled dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Vemurafenib may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• tiredness
• joint, muscle, arm, leg, or back pain
• redness or swelling in hands, feet, ankles, or lower legs
• change in sense of taste
• headache
• hair loss
• dry or itchy skin
• diarrhea
• constipation
• cough

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• changes in skin appearance
• new wart
• skin sore or red bump that bleeds or does not heal
• change in size or color of a mole
• extreme tiredness
• unusual bruising or bleeding
• nausea
• vomiting
• loss of appetite
• pain in the upper right part of the stomach
• yellowing of the skin or eyes
• eye sensitivity to light
• eye redness or pain
• vision changes
• unusual thickening of palms of hands
• tightening of the fingers inwards towards the palm
• unusual thickening of soles of feet, that may be painful

If you experience any of the following symptoms of an allergic reaction or severe skin reaction, stop taking vemurafenib and call your doctor immediately or get emergency medical treatment:

• difficulty breathing or swallowing
• rapid, irregular, or pounding heartbeats
• fainting
• rash or redness all over the body
• hives
• peeling or blistering skin
• fever

Vemurafenib may increase the risk that you will develop other cancers. Talk to your doctor about this risk.

Vemurafenib may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can’t be awakened, immediately call emergency services at 911.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body’s response to vemurafenib. Your doctor will check your skin before starting treatment, every 2 months during your treatment, and for up to 6 months after treatment.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

• Zelboraf^®