Litfulo (ritlecitinib) is a brand-name oral capsule prescribed to treat severe alopecia (hair loss) in adults and certain children. As with other drugs, Litfulo can cause side effects, such as headache, diarrhea, and rash.

Litfulo has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). For details, see the “Side effect specifics” section below.

Litfulo 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 Litfulo for alopecia areata in clinical trials:

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

Mild side effects that people taking Litfulo have reported include:

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 FDA approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Litfulo and want to tell the FDA about it, visit MedWatch.

Litfulo may cause serious side effects, although they aren’t common. The list below may not include all possible serious side effects of the drug. For more information, you can refer to the Litfulo prescribing information.

If you develop serious side effects while taking Litfulo, 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 and their symptoms that people taking Litfulo have reported include:

Note: Litfulo has boxed warnings for some of the side effects listed above. For more information, see “Side effect specifics” below.

ALLERGIC REACTION

For some people, Litfulo capsules can cause an allergic reaction.

In general, symptoms of allergic reaction can be mild or serious. You can learn more about possible symptoms in this article.

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 trouble 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 Litfulo capsules, your doctor may recommend taking a different medication instead.

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

Is Litfulo safe for older adults?

It’s possible. In clinical trials, side effects reported by older adults (ages 65 years and older) taking Litfulo were not significantly different from those reported by other adults. However, there were not many adults in these trials, so it’s difficult to know for sure whether the drug is as safe for older adults as other adults.

Litfulo has several boxed warnings, including one for an increased risk of infections. Since older adults generally have a higher risk of infection, they may have an even higher risk with Litfulo. The drug also has a boxed warning about an increased risk of death in certain people over ages 50 years old. For more information, see the “Side effect specifics” section below.

Talk with your doctor or pharmacist if you’d like more information about Litfulo safety in older adults.

Can Litfulo cause long-term side effects?

It’s possible. Long-term side effects include those that can start at any time during treatment or continue even after you stop taking the medication. Examples of these side effects include an increased risk of infections and certain cancers.

Litfulo has boxed warnings about these side effects. For more information, see the “Side effect specifics” section below.

If you have questions or concerns about long-term side effects with Litfulo, talk with your doctor.

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

Increased risk of serious infections

Litfulo has a boxed warning for an increased risk of serious infections. A boxed warning is the most serious warning from the FDA.

Taking Litfulo increases the risk of getting a serious infection, such as pneumonia, shingles, or tuberculosis (TB). Serious infections were not common in the drug’s clinical studies.

Litfulo can raise the risk of infection because it weakens your immune system. In rare cases, such infections could be fatal.

Symptoms of a serious infection may include:

What you can do

Before starting Litfulo, your doctor will likely order a test to determine if you have TB. They’ll also make sure you’ve had certain vaccinations.

Tell your doctor if you have an active infection or infections that keep coming back. They’ll want to treat your infection before prescribing Litfulo. Also, be sure to tell them about any serious infections you have had. Examples include shingles, chickenpox, hepatitis B, or hepatitis C.

If you develop an infection while taking Litfulo, tell your doctor right away. They’ll likely prescribe medication to treat it. They may also recommend temporarily stopping Litfulo until your infection is gone.

Increased risk of death

Litfulo has a boxed warning from the FDA for an increased risk of death.

Litfulo belongs to a class of drugs known as Janus kinase (JAK) inhibitors. Taking a JAK inhibitor may increase the risk of death in certain people. This was seen in people ages 50 years or older who had taken a JAK inhibitor for rheumatoid arthritis (RA) and had at least one risk factor for heart disease. These risk factors include smoking, high blood pressure, and diabetes. (Note that Litfulo is not approved for use in people with RA.)

What you can do

Because of the risk of death with other JAK inhibitors, your doctor will consider your medical history and age before prescribing Litfulo. You and your doctor can discuss the risks and benefits of taking Litfulo for your condition.

Increased risk of cancer

Litfulo also has a boxed warning for an increased risk of cancer. An increased risk of certain cancers has been reported in people who have taken Litfulo in clinical trials. These cancers include non-melanoma skin cancer, lung cancer, and lymphoma.

Symptoms vary depending on the type of cancer. Examples may include:

People who currently smoke or have in the past may have an increased risk of cancer.

What you can do

Be sure to tell your doctor if you’ve had any type of cancer. They’ll discuss the risks and benefits of Litfulo therapy with you before starting treatment. If you notice any of the above symptoms, talk with your doctor right away.

Increased risk of serious cardiovascular problems

Litfulo also has a boxed warning for an increased risk of serious cardiovascular (heart and blood vessel) problems. These problems include stroke, heart attack, and even death.

JAK inhibitors can increase the risk of serious cardiovascular problems in some people taking them for RA. The risk is seen in people ages 50 years and older who have at least one risk factor for heart disease. Examples include high blood pressure, diabetes, and smoking.

Litfulo is a JAK inhibitor but there were no reports of serious cardiovascular problems in the drug’s clinical trials.

Symptoms of a stroke or heart attack may include:

  • dizziness
  • pain or pressure in your chest
  • shortness of breath
  • trouble walking or speaking
  • sudden numbness or weakness affecting only one side of your body

What you can do

If you have symptoms of a stroke or heart attack, call 911 (or your local emergency number) or go to the closest emergency room right away.

Before starting Litfulo, be sure to tell your doctor if you’ve ever had a stroke or heart attack. Also talk with your doctor about risk factors you may have for heart disease. Your doctor will discuss the risks and benefits of Litfulo therapy with you before starting treatment.

Increased risk of blood clots

Litfulo has a boxed warning for an increased risk of blood clots.

Litfulo can increase the risk of blood clots. These include blood clots in your lungs (pulmonary embolism), legs (deep vein thrombosis), or eyes. If you’ve ever had a blood clot or you have risk factors for them, your risk with Litfulo may be higher.

  • shortness of breath
  • sudden chest pain
  • warmth, pain, swelling, redness, or discoloration in one or both legs
  • sudden change in vision, especially in one eye

What you can do

If you have symptoms of a blood clot, talk with your doctor right away. If the symptoms seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Due to this risk, your doctor may not prescribe Litfulo if you have an increased risk of blood clots. Risk factors include smoking, taking certain medications such as birth control pills, and a family history of blood clots. Your doctor can determine whether Litfulo is a good treatment option for you.

Below is important information you should consider before taking Litfulo.

Litfulo has boxed warnings. A boxed warning is the most serious warning from the FDA. For details, see the “Side effect specifics” section above.

Other precautions

Before taking Litfulo, discuss your health history with your doctor. Litfulo 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:

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.