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Mekinist Side Effects

Generic Name: trametinib

Note: This page contains information about the side effects of trametinib. Some of the dosage forms included on this document 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

In addition to its needed effects, some unwanted effects may be caused by trametinib (the active ingredient contained in Mekinist). 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 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
  • shortness of breath
  • 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:
  • Cough
  • fever
  • Change in vision
  • fever
  • 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

Minor Side Effects

Some of the side effects that can occur with trametinib 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:
  • Abdominal or stomach pain
  • 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
  • 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.

Not all side effects for Mekinist 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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