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Mekinist Side Effects

Generic Name: trametinib

Note: This document contains side effect information about trametinib. Some of the dosage forms listed on this page may not apply to the brand name Mekinist.

In Summary

Common side effects of Mekinist include: acneiform eruption, cardiomyopathy, decreased left ventricular ejection fraction, dermatitis, palmar-plantar erythrodysesthesia, skin rash, and erythema. Other side effects include: cardiac failure. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to trametinib: oral tablet

Along with its needed effects, trametinib (the active ingredient contained in Mekinist) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking trametinib:

More common
  • Bleeding from the rectum or bloody stools
  • bleeding gums
  • blemishes on the skin
  • blistering, crusting, irritation, itching, or reddening of the skin
  • bloating or swelling of the face, arms, hands, lower legs, or feet
  • bloody nose
  • blurred vision
  • chest discomfort or pain
  • cracked, dry, or scaly skin
  • coughing up blood
  • decreased urine output
  • diarrhea
  • difficulty with breathing or swallowing
  • dilated neck veins
  • dizziness
  • extreme fatigue
  • faintness
  • fast, slow, irregular, or pounding heartbeat
  • headache
  • increased menstrual flow or vaginal bleeding
  • irregular breathing
  • irregular heartbeat
  • lightheadedness, dizziness, or fainting
  • nervousness
  • nosebleeds
  • paralysis
  • pimples
  • pounding in the ears
  • prolonged bleeding from cuts
  • rapid weight gain
  • rash
  • red or black, tarry stools
  • red or dark brown urine
  • redness, swelling, or pain of the skin
  • scaling of the skin on the hands and feet
  • tightness in the chest
  • tingling of the hands and feet
  • ulceration of the skin
  • unusual tiredness or weakness
  • unusual weight gain or loss
Less common Rare
  • Change in vision
  • seeing flashes or sparks of light
  • seeing floating spots before the eyes, or a veil or curtain across part of your vision
  • stomach cramps, pain, or tenderness
  • watery or bloody diarrhea

Some side effects of trametinib may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Burning, itching, and pain in hairy areas, pus at the root of the hair
  • canker sores
  • change in taste
  • dark-colored urine
  • dry eyes
  • dry mouth
  • dry skin
  • itching, pain, redness, swelling, tenderness, or warmth on the skin
  • loosening of the fingernails
  • loss of taste
  • muscle cramps or spasms
  • muscle pain or stiffness
  • redness or soreness around the fingernails
  • sores, ulcers, or white spots on the lips or tongue or inside the mouth
  • stomach pain
  • swelling or inflammation of the mouth
  • thirst

For Healthcare Professionals

Applies to trametinib: oral tablet


Rash and decreased LVEF were the most common reasons cited for dose reductions of trametinib (the active ingredient contained in Mekinist)

The most common adverse reactions resulting in permanent discontinuation of trametinib were decreased left ventricular ejection fraction (LVEF), pneumonitis, renal failure, diarrhea, and rash.[Ref]


Very common (10% or more): Lymphedema (43%), hypertension (15%), hemorrhage (13%)
Frequency not reported: Bradycardia[Ref]


Very common (10% or more): rash (57%), dermatitis acneiform (19%), dry skin (11%), pruritus (10%), paronychia (10%)
Frequency not reported: Folliculitis, rash pustular, cellulitis[Ref]


Very common (10% or more): Diarrhea (43%), stomatitis (15%), abdominal pain (13%)
Frequency not reported: Xerostomia[Ref]


Very common (10% or more): Anemia (38%)[Ref]


Very common (10% or more): Increased aspartate aminotransferase (AST) (60%), Increased alanine aminotransferase (ALT) (39%)[Ref]


Very common (10% or more): Hypoalbuminemia (42%), increased alkaline phosphatase (24%)[Ref]


Frequency not reported: Rhabdomyolysis[Ref]

Nervous system

Frequency not reported: Dizziness, dysgeusia[Ref]


Frequency not reported: Vision blurred, dry eye[Ref]


1. "Product Information. Mekinist (trametinib)." GlaxoSmithKline, Research Triangle Park, NC.

Some side effects of Mekinist may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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