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Cotellic Side Effects

Generic Name: cobimetinib

Note: This page contains information about the side effects of cobimetinib. Some of the dosage forms included on this document may not apply to the brand name Cotellic.

In Summary

Common side effects of Cotellic include: skin photosensitivity. Other side effects include: increased creatine phosphokinase. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to cobimetinib: oral tablet

In addition to its needed effects, some unwanted effects may be caused by cobimetinib (the active ingredient contained in Cotellic). In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking cobimetinib:

More common:
  • Abdominal or stomach pain or tenderness
  • bleeding gums
  • blurred vision or any other change in vision
  • chest discomfort or pain
  • chills
  • clay colored stools
  • coughing up blood
  • dark urine
  • decreased appetite
  • difficulty in breathing or swallowing
  • dizziness
  • faintness
  • fast irregular or pounding heartbeat
  • fever
  • headache
  • increased menstrual flow or vaginal bleeding
  • increased sensitivity of the skin to sunlight
  • itching or skin rash
  • loss of appetite
  • muscle cramps or spasms
  • muscle pain or stiffness
  • nausea and vomiting
  • nervousness
  • nosebleeds
  • paralysis
  • pounding in the ears
  • prolonged bleeding from cuts
  • red or black, tarry stools
  • red or dark brown urine
  • redness or other discoloration of the skin
  • seeing flashes or sparks of light
  • seeing floating spots before the eyes, or a veil or curtain appearing across part of vision
  • severe sunburn
  • slow or fast heartbeat
  • swelling of the feet or lower legs
  • unusual tiredness or weakness
  • yellow eyes or skin

Minor Side Effects

Some of the side effects that can occur with cobimetinib may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:
  • Acne or pimples
  • diarrhea
  • nausea
  • swelling or inflammation of the mouth
  • vomiting

For Healthcare Professionals

Applies to cobimetinib: oral tablet


The most commonly reported adverse reactions (more than 35%) were increased creatinine, increased CPK, lymphopenia, increased AST, increased alkaline phosphatase, increased ALT, hypophosphatemia, anemia, increased gamma-glutamyltransferase, diarrhea, photosensitivity reactions, hypoalbuminemia, nausea, and hyponatremia.[Ref]


Very common (10% or more): Increased creatinine (99.6%)[Ref]


Very common (10% or more): Increased CPK (79%)[Ref]


Very common (10% or more): Increased AST (73%), increased alkaline phosphatase (71%), increased ALT (68%), increased gamma-glutamyltransferase (65%)
Frequency not reported: Increased total bilirubin[Ref]


Very common (10% or more): Lymphopenia (73%), anemia (69%), thrombocytopenia (18%)[Ref]


Very common (10% or more): Hypophosphatemia (68%), hypoalbuminemia (42%), hyponatremia (38%), hyperkalemia (26%), hypokalemia (25%), hypocalcemia (24%)[Ref]


Very common (10% or more): Diarrhea (60%), nausea (41%), vomiting (24%), stomatitis (14%)[Ref]


Very common (10% or more): Photosensitivity reactions (47%), acneiform dermatitis (16%), alopecia (15%), hyperkeratosis (11%), erythema (10%)
Frequency not reported: Rash[Ref]


Very common (10% or more): Pyrexia (28%), hemorrhage (13%), chills (10%)[Ref]

Reported hemorrhage cases included various types of hemorrhages (rectal, hemorrhoidal, gastrointestinal tract, uterine, vaginal, pulmonary, cerebral, subarachnoid, ocular, eye, conjunctival, retinal; reproductive system); melena, hematemesis; hematochezia; gingival bleeding; metrorrhagia; hemorrhagic ovarian cyst; menometrorrhagia; menorrhagia; hemoptysis; subgaleal hematoma; hematuria; epistaxis; contusion; traumatic hematoma; ecchymosis; purpura; and nail bed bleeding.[Ref]


Very common (10% or more): Decreased LVEF (26%), hypertension (15%)[Ref]


Very common (10% or more): Serous retinopathy (26%), impaired vision (15%), chorioretinopathy (13%), retinal detachment (12%)
Uncommon (0.1% to 1%): Retinal vein occlusion[Ref]


Common (1% to 10%): Cutaneous squamous cell carcinoma/keratoacanthoma, basal cell carcinoma
Uncommon (0.1% to 1%): Second primary melanoma, non-cutaneous malignancies[Ref]


1. "Product Information. Cotellic (cobimetinib)." Genentech, South San Francisco, CA.

Not all side effects for Cotellic may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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