Mekinist (trametinib) is a brand-name drug that’s prescribed for certain types of cancers in adults and some children. As with other drugs, Mekinist can cause side effects, such as fever, skin rash, and diarrhea.

Mekinist can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Mekinist in clinical trials. These side effects can vary depending on whether the drug is used alone or in combination with dabrafenib (Tafinlar), another cancer drug.

More common side effects in people taking Mekinist alone include:

  • diarrhea
  • abdominal pain
  • stomatitis (mouth sores)
  • swelling of the face, arms, or legs
  • mild skin rash*

More common side effects in people taking Mekinist in combination with dabrafenib include:

  • nausea or vomiting
  • fever or chills
  • diarrhea
  • fatigue (lack of energy)
  • mild skin rash*

* For more information about this side effect, see “Side effect specifics.”

Mild side effects can occur with Mekinist use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Mekinist’s prescribing information.

Mild side effects that have been reported with Mekinist include:

  • diarrhea
  • abdominal pain
  • nausea and vomiting
  • fever or chills
  • fatigue
  • headache
  • edema (fluid buildup)
  • joint or muscle pain
  • cough
  • mild skin rash*

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Mekinist and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics.”

Mekinist may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Mekinist’s prescribing information.

If you develop serious side effects while taking Mekinist, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

  • heart problems, including heart failure, which may include symptoms such as:
  • blood clots, such as deep vein thrombosis (DVT) and pulmonary embolism (PE), which may include symptoms such as:
    • pain, swelling, or warmth in an arm or leg
    • sudden cough or shortness of breath
    • chest pain
  • lung problems, such as interstitial lung disease (swelling and scarring in the lungs), which may include symptoms such as:
    • new or worsening cough
    • shortness of breath
  • development of new cancers, which may include symptoms such as:
    • skin sore that bleeds or doesn’t heal
    • a mole that changes size or color
    • a new mole, wart, or lump
    • unexpected weight loss
  • hemophagocytic lymphohistiocytosis (a condition caused by an overactive immune system), which may include symptoms such as:
  • colitis (inflammation in the colon) or gastrointestinal (GI) perforation (tear in the stomach or intestine), which may include symptoms such as:
  • high blood pressure, which typically doesn’t cause symptoms, but severe high blood pressure may include symptoms such as:
    • dizziness
    • severe headache
    • blurry vision
  • eye problems, such as retinal vein occlusion (blocked veins in the back of the eye), which may include symptoms such as:
    • eye pain, redness, or swelling
    • vision changes
    • seeing halos around lights or flashes of light
  • high blood sugar, which may include symptoms such as:
    • increased thirst
    • urinating more than usual
  • neutropenia (low white blood cell count), which may include symptoms such as:
    • cough
    • fever
    • changes in mental status
    • redness or other color changes, or swelling around wounds
    • flu-like symptoms
  • serious skin rash*
  • serious bleeding problems*
  • fever*

* For more information about this side effect, see “Side effect specifics.”

ALLERGIC REACTION

For some people, Mekinist can cause an allergic reaction. In general, symptoms of an allergic reaction can be mild or serious.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Mekinist, your doctor may recommend taking a different medication instead.

Mekinist may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

How long do side effects of Mekinist last?

Side effects of Mekinist are most likely to occur during the first 3 months and may go away over time as your body adjusts to the drug.

However, it’s important to note that Mekinist with or without dabrafenib is meant to be taken as a long-term treatment. You’ll take it as long as it’s working to treat your condition and the side effects are manageable. Your doctor may adjust your dose of Mekinist or recommend other ways to help its manage side effects.

If your doctor recommends you stop taking Mekinist, most side effects will go away within a month or two after you stop treatment

Talk with your doctor for more information on what side effects to expect and how long they will last.

Can Mekinest cause hair loss?

It’s possible. Hair loss wasn’t reported as a side effect in clinical trials when Mekinist was used alone. However, hair loss was reported in children when Mekinist was used in combination with dabrafenib. But this side effect was less common.

A variety of reasons may cause hair loss. If you experience hair loss during treatment with Mekinist, talk with your doctor. They can help determine the cause and may suggest ways to help manage it.

Learn more about some of the side effects that Mekinist may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Mekinist.

Skin rash

Skin rash is a common side effect reported in clinical trials of Mekinist. Most skin rashes were mild. However in some cases, a rash may be a sign of a serious and life threatening skin reaction, which may need to be treated in the hospital.

Symptoms of a serious skin reaction may include:

  • a rash that blisters or peels
  • flu-like symptoms
  • blisters around your mouth or eyes
  • swollen lymph nodes

What you can do

Your doctor can suggest ways to help prevent or manage a skin rash. This may include limiting exposure to the sun or using a moisturizing cream to help soothe rash symptoms.

Talk with your doctor right away if you develop any symptoms of a serious rash or skin reaction.

Bleeding problems

Hemorrhage (bleeding which may be serious) can occur while taking Mekinist. This was a common side effect reported in Mekinist’s clinical trials. Severe bleeding can happen in the brain or stomach, and in rare cases, it can be life threatening.

A hemorrhage may cause symptoms which include:

  • unexplained bruising
  • nosebleeds
  • severe headache
  • vision problems
  • feeling dizzy or weak
  • blood in your urine or stool
  • vomiting blood or vomit that looks like coffee grounds

What you can do

If you experience unusual bleeding symptoms while taking Mekinist, talk with your doctor right away. If you feel the symptoms are life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Fever

Fever was one of the most common side effects reported in Mekinist’s clinical trials. A fever may happen often and can be severe in some cases, especially if you are taking Mekinist and dabrafenib together. It may be caused by an infection. Other side effects, such as low blood pressure, dizziness, dehydration, or kidney problems, can sometimes occur with a fever.

What you can do

Your doctor will likely recommend that you check your temperature regularly. Talk with your doctor right away if you have a fever during treatment with Mekinist. They will likely treat the fever and infection if needed. If you continue to have fevers, they may temporarily or permanently stop treatment with Mekinist. However, don’t stop taking Mekinist without first talking with your doctor.

Before taking Mekinist, discuss your health history with your doctor. Mekinist may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

  • stomach problems
  • liver or kidney problems
  • breathing or lung problems
  • bleeding problems
  • diabetes
  • heart problems, such as heart failure
  • high blood pressure
  • colitis
  • eye problems, such as glaucoma
  • previous allergic reaction to this or a similar drug
  • pregnancy
  • breastfeeding

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.