Reviewed on 1/31/2023

What Is Vemurafenib and How Does It Work?

Vemurafenib is a prescription medication used for the treatment of malignant melanoma and Erdheim-Chester Disease. 

  • Vemurafenib is available under the following different brand names: Zelboraf

What Are Side Effects Associated with Using Vemurafenib?

Common side effects of Vemurafenib include:

  • joint pain,
  • tiredness,
  • nausea,
  • hair loss,
  • rash or itching,
  • skin growths (skin tags),
  • blurred vision,
  • increased sensitivity of your eyes to light,
  • hair loss,
  • thickening skin,
  • rough scaly patches on the skin,
  • dry skin,
  • skin redness,
  • muscle pain,
  • pain in extremities,
  • back pain,
  • fatigue,
  • swelling of extremities,
  • fever,
  • weakness,
  • diarrhea,
  • vomiting,
  • constipation,
  • headache,
  • changes in taste,
  • decreased appetite,
  • cough, and
  • sunburn.

Serious side effects of Vemurafenib include:

  • hives,
  • difficulty breathing,
  • swelling of the face, lips, tongue, or throat,
  • fever,
  • sore throat,
  • burning in the eyes,
  • skin pain,
  • red or purple skin rash that spreads and causes blistering and peeling,
  • swollen glands,
  • muscle aches,
  • severe weakness,
  • unusual bruising,
  • yellowing of the skin or eyes (jaundice),
  • a new wart or lesion,
  • skin sore or red bump that bleeds or does not heal,
  • any change in the size or color of a mole,
  • unusual thickening of tissues under the skin on the palms of the hands or the soles of the feet,
  • finger or fingers that feel tight or are bent inward,
  • fast or pounding heartbeats,
  • fluttering in the chest,
  • shortness of breath,
  • sudden dizziness,
  • vision changes,
  • eye pain or swelling,
  • severe eye redness,
  • small white or yellow patches on the surface of the eye,
  • stomach pain (upper right side),
  • nausea,
  • vomiting,
  • loss of appetite,
  • dark urine, and
  • clay-colored stools

Rare side effects of Vemurafenib include:

  • none 

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out. 

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are the Dosages of Vemurafenib?

Adult dosage


  • 240 mg

Malignant Melanoma

Adult dosage

  • 960 mg (4 x 240 mg tablets) orally every 12 hours (administer approximately 12 hours apart)

Erdheim-Chester Disease

Adult dosage

  • 960 mg (4 x 240 mg tablets) orally every 12 hours (administer approximately 12 hours apart)

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Other Drugs Interact with Vemurafenib?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Vemurafenib has severe interactions with the following drugs:
  • Vemurafenib has serious interactions with at least 183 other drugs.
  • Vemurafenib has moderate interactions with at least 123 other drugs.
  • Vemurafenib has minor interactions with the following drugs:

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Vemurafenib?


  • None

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Vemurafenib?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Vemurafenib?”


  • Anaphylaxis and other serious hypersensitivity reactions reported during treatment and upon reinitiation, including generalized rash and erythema, hypotension, and drug reaction with eosinophilia and systemic symptoms (DRESS syndrome); permanently discontinue.
  • Severe dermatologic reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, were reported; discontinue treatment.
  • Elevated liver enzymes may occur; monitor liver enzymes and bilirubin before treatment initiation and then monthly or as clinically indicated.
  • Liver injury leading to functional hepatic impairment, including coagulopathy or another organ dysfunction, can occur with vemurafenib
  • Mild-to-moderate photosensitivity reported; advise patients to avoid sun exposure and wear protective clothing and use a broad-spectrum UVA/UVB sunscreen and lip balm (SPF more than 30) when outdoors.
  • Serious ophthalmologic reactions, including uveitis, iritis, blurry vision, photophobia, and retinal vein occlusion reported.
  • Based on the mechanism of action, can cause fetal harm when administered to pregnant women; avoid use during pregnancy and use effective contraception (see Pregnancy
  • Severe cases of radiation sensitization and recall reported.
  • Renal failure, including acute interstitial nephritis and acute tubular necrosis, was reported; measure serum creatinine before initiation of therapy and periodically during treatment.
  • Dupuytren’s contracture and plantar fascial fibromatosis were reported; the majority of cases, mild to moderate, but severe disabling cases of Dupuytren’s contracture also reported
  • BRAF mutation test required to confirm eligibility for treatment; has not been studied with wild-type BRAF melanoma.
  • New primary malignancies
    • Cutaneous squamous cell carcinomas (cuSCC) and keratoacanthoma occurred in 24% of patients.
    • Unresectable or metastatic melanoma, new primary malignant melanoma occurred in 2.1% of patients.
    • Perform dermatologic evaluations prior to treatment initiation and every 2 months while on therapy.
    • Manage with excision and continue treatment without dose adjustment; consider monitoring for 6 months following discontinuation of treatment.
    • Noncutaneous squamous cell carcinomas (non-cuSCC) of the head and neck can; monitor for signs or symptoms of new non-cuSCC
    • Based on the mechanism of action, vemurafenib may promote malignancies associated with activation of RAS through mutation or other mechanisms; monitor for signs or symptoms of other malignancies
    • Cases of myeloid neoplasms amongst patients with Erdheim-Chester disease (ECD) reported, including in patients who have received therapy; monitoring complete blood count in ECD patients with co-existing myeloid malignancies recommended
  • QT prolongation
    • Concentration-dependent QT prolongation reported
    • Do not start treatment in patients with uncorrectable electrolyte abnormalities, QTc above 500 ms, or long QT syndrome, or in patients who are taking medication associated with QT prolongation
    • Monitor ECG and electrolytes before treatment initiation and after dose modification
    • Monitor ECGs at day 15, monthly during the first 3 months of treatment, and then every 3 months thereafter, or more often as clinically indicated
    • If the QTc exceeds 500 ms, temporarily interrupt treatment, correct electrolyte abnormalities, and control for cardiac risk factors for QT prolongation (see Dosage Modifications)
    • Permanently discontinue if QTc interval remains above 500 ms and increases above 60 ms from pretreatment values after controlling cardiac risk factors for QT prolongation (e.g., electrolyte abnormalities, congestive heart failure, and bradyarrhythmias)
  • Drug interactions overview
    • Vemurafenib is a CYP3A4 substrate and CYP1A2 inhibitor
    • Avoid coadministration of vemurafenib with strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, saquinavir, ritonavir, indinavir, nelfinavir, voriconazole) and replace and use alternative drugs when possible
    • Avoid coadministration with strong CYP3A4 inducers; if unavoidable, increase vemurafenib dose (see Dosage Modifications)
    • Avoid concomitant use of vemurafenib with drugs having a narrow therapeutic window that is predominantly metabolized by CYP1A2; coadministration of vemurafenib with tizanidine, a sensitive CYP1A2 substrate, increased tizanidine systemic exposure by 4.7-fold
    • Avoid concurrent use of P-gp substrates known to have a narrow therapeutic window; if medication use is unavoidable, consider a dose reduction of P-gp substrates with narrow therapeutic indices
    • Increases in transaminases and bilirubin occurred in a majority of patients who are concurrently using ipilimumab and vemurafenib and peak plasma concentration; if unable to avoid, adjust relugolix dose

Pregnancy and Lactation

  • There are no available data on the use of vemurafenib in pregnant women to determine the drug-associated risk
  • Based on the mechanism of action, therapy can cause fetal harm when administered to pregnant women; advise females of reproductive potential to use effective contraception during treatment and for 2 weeks after the final dose
  • Lactation
    • There is no information available regarding the presence of vemurafenib in human milk, its effects on the breastfed infant, or its effects on milk production; because of the potential for serious adverse reactions in a breastfed infant, including malignancy, severe dermatologic reactions, QT prolongation, hepatotoxicity, photosensitivity, and ophthalmologic toxicity, advise women not to breastfeed during treatment and for 2 weeks after the final dose

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