If you have a certain type of cancer, your doctor might suggest Tafinlar as a treatment option for you.

Tafinlar is a prescription medication that’s used in adults to treat certain kinds of the following cancers:

For some uses, Tafinlar is taken with the drug Mekinist (trametinib).

The active ingredient in Tafinlar is dabrafenib. An active ingredient is what makes a drug work. Tafinlar comes as a capsule that you swallow.

Tafinlar is meant to be taken long term.

For more information about Tafinlar, including details about its uses, see this in-depth article.

Like other drugs, Tafinlar can cause mild to serious side effects. Keep reading to learn more.

Listed below are a few of the more common side effects reported by people who took Tafinlar in studies.* The side effects can vary depending on what condition the drug is being used to treat. Not everyone who takes Tafinlar will have these side effects.

More common side effects in people taking Tafinlar by itself for melanoma that has spread or cannot be treated with surgery include:

More common side effects in people taking Tafinlar with Mekinist for melanoma that has spread or cannot be treated with surgery include:

More common side effects in people taking Tafinlar with Mekinist for melanoma that has been treated with surgery include:

More common side effects in people taking Tafinlar with Mekinist for non-small cell lung cancer include:

* Side effects that occurred when people took Tafinlar with Mekinist for anaplastic thyroid cancer weren’t reported in studies, so their frequency is unknown. But they are expected to be similar to what people reported when taking Tafinlar with Mekinist for other conditions.

Tafinlar may cause mild side effects in some people when taken by itself or together with Mekinist. Listed below are examples of mild side effects that have been reported with Tafinlar. Side effects may vary depending on the condition Tafinlar is being used to treat.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or bother you, talk with your doctor or pharmacist. And don’t stop taking Tafinlar unless your doctor recommends it.

Tafinlar may cause mild side effects other than the ones listed above. See the Tafinlar prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Tafinlar, visit MedWatch.

Serious side effects can occur while taking Tafinlar, but they aren’t common. Examples of serious side effects that have been reported with Tafinlar when taken alone or when taken with Mekinist include:

* To learn more about this side effect, see the “Side effects explained” section below.

If you develop serious side effects while taking Tafinlar, 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.

Get answers to some frequently asked questions about Tafinlar’s side effects.

Does taking Tafinlar and Mekinist in combination cause different side effects compared with taking Tafinlar alone?

It’s possible. You may experience different side effects depending on whether you take Tafinlar with Mekinist. And the side effects can vary depending on the kind of cancer you’re using these drugs to treat.

For example, in studies of Tafinlar, fever was reported regardless of whether the drug was taken with Mekinist and what cancer was being treated. But shortness of breath only happened in people who took Tafinlar with Mekinist to treat a certain kind of non-small cell lung cancer.

For more information, see the “What are the more common side effects of Tafinlar?” section above. Your doctor or pharmacist can also discuss the different side effects that Tafinlar may cause alone or with Mekinist.

Are the side effects of Tafinlar and Mekinist similar to those caused by chemotherapy?

Not necessarily. Tafinlar and Mekinist are targeted therapies for cancer. Targeted therapies help treat cancer by blocking specific molecules in the cancer itself. This is different from chemotherapy, which affects healthy cells as well as cancer cells in the body.

As a result, chemotherapy may have a higher risk of side effects than targeted therapies. But the specific side effects you may experience from chemotherapy depend on the drug you take and what type of cancer you may have.

For more information about how the side effects of Tafinlar and Mekinist compare with those of chemotherapy, talk with your doctor or pharmacist.

Learn more about some of the side effects Tafinlar may cause.

Eye-related side effects

In studies, Tafinlar taken alone or with Mekinist caused ocular (eye-related) side effects, such as blurry vision and uveitis. These side effects were not common.

Blurry vision can be a symptom of uveitis. Other symptoms of uveitis include:

What might help

If you have blurry vision with uveitis, talk with your doctor. They’ll recommend what to do if you have this side effect. Your doctor may suggest you have an eye exam to see if uveitis may be the cause.

If you notice eye pain or changes in your vision, let your doctor know right away. They may prescribe certain types of eye drops to help ease your symptoms. They may also decrease your dosage of Tafinlar or tell you to stop taking it for a while.

Bleeding

In studies, bleeding problems were common in people who took Tafinlar with Mekinist for non-small cell lung cancer. But this side effect can also happen when Tafinlar is taken alone.

Tafinlar may cause bleeding in the brain, which can be life threatening.

It may also cause serious bleeding problems in the digestive tract. Symptoms include:

Other symptoms of bleeding to watch out for include:

What might help

If you notice any symptoms of bleeding, tell your doctor right away. They may recommend that you stop treatment until the bleeding goes away.

If you have serious bleeding problems from Tafinlar, your doctor will likely recommend a different treatment for your cancer.

Risk of new cancers

In studies, new skin cancers were a rare side effect seen in people who took Tafinlar alone or together with Mekinist. Some people developed cancer that affected other parts of the body.

Symptoms of skin cancer include:

  • new warts or growths on your skin
  • new moles or changes in the color or size of existing moles
  • bleeding skin sores that won’t heal

What might help

Before you start taking Tafinlar, you’ll likely need to see a dermatologist. They’ll check your skin for signs of new cancer. You’ll continue to have regular skin checks with the dermatologist during treatment. And they’ll check your skin again about 6 months after your last Tafinlar dose.

Be sure to wear sunscreen and protective clothing if you’re out in the sun, and avoid using tanning beds. If you notice any changes in your skin, tell your doctor right away. They’ll try to determine what’s causing those changes and recommend the right treatment options if needed.

To learn about cancers Tafinlar may cause that aren’t skin-related, talk with your doctor. They can tell you about other cancer symptoms to watch for while taking Tafinlar.

Increased blood sugar

In studies of Tafinlar, some people experienced increased blood sugar or worsening diabetes.

Symptoms of high blood sugar include:

What might help

If you have diabetes or prediabetes, your doctor may recommend checking your blood sugar more closely while taking Tafinlar.

If you have any symptoms of high blood sugar, let your doctor know right away. They’ll likely check your blood sugar. If you have high blood sugar, your doctor may make changes to any medications you take for diabetes. This could include changing the dosage of a medication you’re already taking or switching to different medication instead.

Allergic reaction

Like most drugs, Tafinlar can cause an allergic reaction in some people. But this side effect wasn’t common in studies of the drug.

Symptoms can be mild to serious and can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, usually in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms. Examples include:

  • an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you’ve had a mild allergic reaction to Tafinlar, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Tafinlar, they may have you switch to a different treatment.

Keeping track of side effects

During your Tafinlar treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were taking when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how it affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Tafinlar affects you. They can then use this information to adjust your treatment plan if needed.

Tafinlar may not be right for you if you have certain medical conditions. These are known as drug-condition interactions. Other factors may also affect whether Tafinlar is a good treatment option for you.

Talk with your doctor about your health history before starting Tafinlar. The list below includes factors to consider.

Vision or heart problems. Studies of Tafinlar did not include people with serious eye or heart problems. So it’s not known how Tafinlar may affect people with such problems. Before starting treatment with Tafinlar, let your doctor know about any eye or heart problems you have or have had in the past.

G6PD deficiency. If you have G6PD deficiency, taking Tafinlar may increase your risk of hemolytic anemia. Before you start taking Tafinlar, let your doctor know if you have this condition. They’ll monitor you closely for hemolytic anemia and let you know what symptoms to watch for.

Prediabetes or diabetes. Tafinlar may cause increased blood sugar. If you have diabetes or prediabetes, this drug can make it difficult to manage your blood sugar levels. Before starting treatment with Tafinlar, tell your doctor if you have diabetes or prediabetes. They’ll likely have you check your blood sugar more often, and they may suggest other changes to help manage your blood sugar.

Serious liver or kidney problems. People who have serious liver or kidney problems were not included in studies of Tafinlar. So it’s unknown how Tafinlar may affect people with these problems. If you have or have had any problems with your liver or kidneys, tell your doctor before starting treatment with Tafinlar.

Allergic reaction. If you’ve had an allergic reaction to Tafinlar or any of its ingredients, your doctor will likely not prescribe Tafinlar. Ask them what other medications are better options for you.

Alcohol and Tafinlar

It’s not known if alcohol interacts with Tafinlar. If you have concerns about drinking alcohol with Tafinlar, talk with your doctor.

Pregnancy and breastfeeding while taking Tafinlar

Tafinlar is not safe to take during pregnancy.

If you can become pregnant, your doctor will have you take a pregnancy test before prescribing Tafinlar to confirm that you are not pregnant.

To prevent pregnancy while taking Tafinlar, if you or your partner can become pregnant, it’s recommended that you use a barrier method such as condoms. You’ll need to continue using this form of birth control for 2 weeks after your last dose of the drug.

If you become pregnant while taking Tafinlar, tell your doctor right away.

It’s not known if Tafinlar passes into breast milk. It’s recommended to avoid breastfeeding during treatment with Tafinlar and for 2 weeks after your last dose.

If you’re breastfeeding or planning to breastfeed, talk with your doctor about healthy ways to feed your baby during treatment.

Tafinlar taken alone or with Mekinist can cause side effects in some people. Most of these are mild and won’t interfere with treatment. However, some can be serious and may require stopping treatment or taking a lower dosage of the drug.

If you’re wondering about Tafinlar’s side effects, talk with your doctor or pharmacist. Ask questions to get the answers you need to feel confident about your cancer treatment. Here are a few to get you started:

  • How can I manage side effects from Tafinlar?
  • I have other health problems besides cancer. Do I have a higher risk of side effects from Tafinlar?
  • What could happen if I become pregnant during Tafinlar treatment?

Q:

I’m hoping to become pregnant after I’m done taking Tafinlar. Can this drug affect my fertility?

Anonymous

A:

Yes, it’s possible that Tafinlar may affect fertility.

Studies of Tafinlar in animals found that fertility decreased in both males and females. But this kind of testing has not been done in humans. And animal studies do not always indicate what will happen in humans.

If you or your partner have concerns about fertility, talk with your doctor. They may recommend planning ahead for pregnancy before starting treatment with Tafinlar. If you can become pregnant, freezing your eggs might be an option to explore.

For more information about ways to preserve fertility prior to cancer treatments, talk with your doctor.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline 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.