Vemurafenib belongs to a group of cancer fighting medications called antineoplastics, and more specifically to a group of medications called protein kinase inhibitors. Vemurafenib works by recognizing and attaching to certain types of cancer cells. This may slow down or stop cancers from growing and dividing.

Vemurafenib is used in adults to treat melanoma, a type of skin cancer, that has a mutation (a change) in the "BRAF" gene and that cannot be removed by surgery or has spread to other parts of the body. People should have their cancer tested for this change in the "BRAF" gene before starting this medication.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The usual dose of vemurafenib is 960 mg (4 tablets) once in the morning and 960 mg (4 tablets) once in the evening, about 12 hours apart. You may take this medication on an empty stomach or with food as long as you take it the same way each time. Swallow the tablets whole with a glass of water. Do not crush or chew the tablets. Avoid drinking grapefruit juice while you are taking vemurafenib.

If you vomit soon after taking the medication, do not take another dose to replace the vomited dose.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

If you miss a dose and it is more than 4 hours before your next dose, take it as soon as possible and continue with your regular schedule. If it is less than 4 hours before your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g., down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

240 mg 
Each oval, biconvex, pinkish white to orange white, film-coated tablet with "VEM" engraved on one side, contains vemurafenib 240 mg. Nonmedicinal ingredients: colloidal anhydrous silica, croscarmellose sodium, hydroxypropyl cellulose, hydroxypropyl methylcellulose acetate succinate (HPMC-AS), and magnesium stearate. Film-coating contains iron oxide red (E172), macrogol 3350, polyvinyl alcohol, talc, and titanium dioxide (E171).

Do not take vemurafenib if you are allergic to vemurafenib or any ingredients of the medication.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• back pain
• constipation
• cough
• diarrhea
• dizziness
• fever
• hair loss
• headache
• high blood pressure
• inflammation of the hair root
• loss of appetite
• nausea
• pain in joint, muscle, back, or extremities
• rash, itching, dry skin
• redness, skin peeling, or blisters on hand and feet (Palmar plantar syndrome)
• skin problems, including warts
• sun sensitivity
• taste changes
• thickening of the tissues under the soles of feet and palms of hands
• tingling or burning sensation in hands and feet (peripheral neuropathy)
• tiredness
• vomiting
• weight loss

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• dehydration (e.g., decreased urine, dry skin, dry and sticky mouth, sleepiness, dizziness, headache, thirst, confusion)
• eye pain, redness, or swelling
• heartburn
• inflammation in the lungs (e.g., fever, chills, shortness of breath, cough)
• pain when swallowing
• signs and symptoms of cutaneous squamous cell cancer including new skin sores, warts, reddish bumps, a sore that bleeds or does not heal, or a change in size, shape, or colour of a mole
• signs of kidney failure (e.g., decreased urine production, swelling in the ankles or feet, fatigue, abdominal pain)
• signs and symptoms of abnormal liver function including skin or whites of the eyes turning yellow, feeling tired, dark or brown coloured urine, nausea or vomiting or not wanting to eat
• signs and symptoms of changes in heart rhythm including feeling dizzy or faint, seizures, palpitations, and feeling a rapid, pounding, or irregular heartbeat
• redness, inflammation, or burning sensation at site of previous radiation therapy
• unusual infections (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• vision changes

Stop taking the medication and seek immediate medical attention if any of the following occur:

• allergic reactions including rash, feeling faint, trouble breathing, or swelling of the face, lips, or tongue
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health.

Abnormal heart rhythms: Vemurafenib can cause abnormal heart rhythms by affecting the electrical activity of the heart. Certain medications (e.g., sotalol, quinidine, thioridazine, chlorpromazine, pimozide, moxifloxacin, mefloquine, pentamidine, arsenic trioxide, tacrolimus) can increase the risk of a type of abnormal heart rhythm called QT prolongation, and should not be used in combination with vemurafenib. You are more at risk for this type of abnormal heart rhythm and its complications if you:

• are female
• are over 65 years of age
• have a family history of sudden cardiac death
• have a history of heart disease or abnormal heart rhythms
• have a slow heart rate
• have congenital prolongation of the QT interval
• have diabetes
• have had a stroke
• have low potassium, magnesium, or calcium levels
• have nutritional deficiencies

Your doctor will monitor your heart rhythm regularly while you are taking this medication with a test called an electrocardiogram (ECG). You should not take this medication if your ECG already shows that you have QT prolongation or if you are taking a medication that can cause QT prolongation

Allergic reactions: Some people may develop a severe allergic reaction to this medication. This reaction may involve a number of organs in the body and may be fatal if not treated quickly. Stop taking the medication and get immediate medical attention if you have symptoms of a severe allergic reaction, including fever, swollen glands, yellowing of the skin or eyes, or flu-like symptoms with skin rash or blistering, swollen face or throat, or difficulty breathing.

Grapefruit juice: Grapefruit juice affects how vemurafenib is removed from the body and may cause too much of the medication to build up in the body and cause possibly harmful side effects. People should not drink grapefruit juice or eat grapefruit at any time while taking this medication for treatment.

High blood pressure: Vemurafenib may increase your blood pressure. Your doctor will monitor your blood pressure while you are taking this medication. If you have high blood pressure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Kidney function: This medication can cause decreased kidney function or kidney failure. If you have a history of decreased kidney function, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience puffy hands, face or feet, high blood pressure, unusual muscle cramping, or darkened urine, this medication may be affecting how well your kidneys are working. If you notice any of these symptoms, contact your doctor as soon as possible.

Liver function: Decreased liver function or liver disease may cause vemurafenib to build up in the body, causing side effects. Vemurafenib may also reduce liver function and can cause liver failure resulting in death. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Your doctor may want to test your liver function regularly with blood tests while you are taking this medication. This often allows reduced liver function to be identified before it becomes too severe.

Other cancers: There have been reports of this medication causing unexpected development of other cancers such as squamous cell carcinoma of the head and neck. It may also speed up the growth of other cancers, such as certain blood cancers and pancreatic cancer. While you are using this medication, your doctor may want to conduct screening tests periodically to ensure that any new cancers are identified and treated as early as possible. If you have any history of cancer other than this melanoma, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pancreatitis: Vemurafenib can cause the pancreas to become inflamed. If you have a history of pancreatitis, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Report signs of pancreatitis such as abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, or swollen abdomen to your doctor immediately.

Radiation treatment: Receiving radiation therapy while taking vemurafenib may result in extreme radiation burns to the treated area. Using this medication while being treated with radiation is not recommended. If you have had radiation treatment in the past, vemurafenib may cause a condition called radiation recall, where the skin that had been treated with radiation becomes inflamed again.

Skin: Vemurafenib may cause changes in your skin, including a new melanoma and cutaneous squamous cell carcinoma. Talk to your doctor if there are any changes in your skin while taking this medication and up to 6 months after the last dose. Changes include new skin sores, warts, reddish bumps, a sore that bleeds or does not heal, or a change in size, shape, or colour of a mole.

Vemurafenib may also cause extra sensitivity to sunlight. Use sunscreen with SPF greater than 30 and protective clothing while taking this medication.

Vision: Vemurafenib may cause inflammation in the eye. It may also contribute to a blockage of the blood vessels that lead out of the eye. If you notice any vision changes or problems, contact your doctor as soon as possible.

Women: Women may be more at risk for experiencing certain side effects from this medication, including rash, sensitivity to sunlight, and joint pain.

Pregnancy: Vemurafenib may harm an unborn child. This medication should not be used during pregnancy unless the benefits outweigh the risks. People who may become pregnant must use an effective birth control method while taking this medication and for at least 6 months after taking the last dose of medication. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if vemurafenib passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children and adolescents: The safety and effectiveness of using this medication have not been established for children and adolescents younger than 18 years of age.

Seniors: People aged 65 years or older may be more at risk for experiencing certain side effects from this medication, including cutaneous squamous cell carcinoma, decreased appetite, and heart conditions.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.