Litfulo (ritlecitinib) is a prescription oral capsule that’s used to treat severe alopecia areata in adults and certain children. Litfulo is a brand-name drug that’s not available in a generic version.

Like most drugs, Litfulo may cause mild or serious side effects. The lists below describe some of the more common side effects that Litfulo may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Litfulo. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a list of some of the mild side effects that Litfulo can cause. To learn about other mild side effects, talk with your doctor or pharmacist or read Litfulo’s prescribing information.

Mild side effects of Litfulo that have been reported include:

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

* To learn more about this side effect, see the “Allergic reaction” section below.

Serious side effects

Serious side effects from Litfulo can occur. If you have serious side effects from Litfulo, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of Litfulo that have been reported include:

* For more information, see the “What should be considered before taking Litfulo?” section.
† To learn more about this side effect, see the “Allergic reaction” section below.

Allergic reaction

Some people may have an allergic reaction to Litfulo.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, usually in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Litfulo. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Litfulo is used to treat severe alopecia areata in adults and in children ages 12 years and older.

With alopecia areata, your immune system mistakenly attacks your hair follicles. These attacks shrink the hair follicles, causing hair loss. You may have patches of hair loss on your scalp or other areas of your body. Or you may lose all hair in a certain area.

Litfulo works to treat alopecia areata by blocking the action of certain proteins that cause your immune system to attack hair follicles. By doing this, it reduces damage to your hair follicles and helps your hair grow back.

Note: Litfulo is not prescribed with other Janus kinase (JAK) inhibitors, as they act similarly to Litfulo. Litfulo also should not be taken with biologic immunomodulators, cyclosporine, or other drugs that strongly suppress your immune system.

Find answers below to some commonly asked questions about Litfulo.

How does Litfulo compare with Olumiant?

Litfulo and baricitinib (Olumiant) belong to the same group of drugs and are both used to treat alopecia areata. In addition, Olumiant is used to treat certain types of rheumatoid arthritis (RA) and COVID-19. (Litfulo isn’t used for these conditions.)

Another difference is that Olumiant is approved for use in adults only. Litfulo is used in adults as well as children ages 12 years and older.

Both drugs come in oral forms. Litfulo comes as a capsule, while Olumiant is available as a tablet.

If you have other questions about how Litfulo and Olumiant compare, talk with your doctor. They can help you find the best treatment for you.

Does Litfulo cause long-term side effects?

It’s possible. Certain long-term side effects of Litfulo may begin during your Litfulo treatment and may continue long after you stop taking it.

Examples of long-term side effects reported in Litfulo’s studies include:

Litfulo has boxed warnings about these risks. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “What should be considered before taking Litfulo?” section below.

You can also talk with your doctor to learn more about possible side effects of Litfulo and how long they may last.

Will Litfulo cure my alopecia?

No, Litfulo does not cure alopecia areata. There’s currently no cure for this condition. However, Litfulo works to help manage your symptoms and regrow hair that has been lost.

If you have other questions about what to expect from your Litfulo treatment, talk with your doctor.

Whether you have health insurance or not, cost may be a factor when you’re considering Litfulo. What you’ll pay for Litfulo may depend on several things, such as your treatment plan and the pharmacy you use.

If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. A program called Pfizer Dermatology Patient Access may be available.

You can also check out this article to learn more about saving money on prescriptions.

Your doctor will recommend the dosage of Litfulo that’s right for you. Below is a commonly used dosage, but always take the dosage your doctor prescribes.

Form and strength

Litfulo comes as an oral capsule in one strength of 50 milligrams (mg).

Recommended dosage

Litfulo is used in adults and in children ages 12 years and older with severe alopecia areata. The recommended dosage is 50 mg taken once per day. You may take your dose with or without food.

Questions about taking Litfulo

Below are some common questions about taking Litfulo.

  • Can Litfulo be chewed, crushed, or split? No, you should not chew, crush, or split Litfulo capsules. You should swallow them whole. If you have trouble swallowing pills, you can ask your doctor or pharmacist for advice.
  • Should I take Litfulo with food? Litfulo can be taken with or without food.
  • Is there a best time of day to take Litfulo? Litfulo can be taken at any time of day, but it’s best to take it around the same time each day. This helps keep a consistent level of the drug in your body, which helps it work effectively.
  • What if I miss a dose of Litfulo? If you miss a dose of Litfulo, take it as soon as you remember. But if your next dose is due in less than 8 hours, skip the missed dose and take the next dose at its usual time. You should not take two doses at once to make up for a missed dose. Doing so could raise your risk of side effects.
  • Will I need to use Litfulo long term? Litfulo is typically used as a long-term treatment. If you and your doctor determine that it’s safe and effective for your condition, you’ll likely take it long term.
  • How long does Litfulo take to work? Litfulo begins to work after you take your first dose. But you likely won’t notice the drug working in your body right away. In studies, people started to notice hair growth around 6 months after starting treatment. Your doctor will order tests throughout your treatment to check whether Litfulo is working to treat your condition.

Overdose

Do not take more Litfulo than your doctor prescribes. Using more than this can lead to harmful effects.

What to do in case you take too much Litfulo

Call your doctor if you think you’ve taken too much Litfulo. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number. Or go to the nearest emergency room.

Below is important information you should consider before taking Litfulo.

Interactions

Taking a drug with certain medications, vaccines, foods, and other things can affect how the drug works. These effects are called interactions.

Litfulo can interact with several other medications. It can also interact with certain supplements as well as certain foods.

Before taking Litfulo, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.

Drug interactions

Below is a list of medications that can interact with Litfulo. This list does not contain all drugs that may interact with Litfulo. If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Drug groupDrug examples
certain drugs that are broken down by the CYP3A enzyme• midazolam (Nayzilam, Seizalam)
• zolpidem (Ambien, Ambien CR, Edular)
certain drugs that are broken down by the CYP1A2 enzyme• theophylline (Theo-24, Elixophyllin, Theochron)
• clozapine (Versacloz, Clozaril)
certain drugs that speed up the action of the CYP3A enzyme• rifampin (Rimactane, Rifadin)
• carbamazepine (Carbatrol, Tegretol, others)

Litfulo and alcohol

Alcohol is not known to interact with Litfulo. But alcohol may worsen some of Litfulo’s side effects, such as headache and dizziness. Because of this, your doctor may recommend that you limit the amount of alcohol you drink during your Litfulo treatment.

If you drink alcohol, talk with your doctor before starting Litfulo treatment.

Other interactions

Litfulo can interact with other substances such as:

  • Vitamins or supplements: Litfulo interacts with St. John’s wort, which is used to ease symptoms of depression and other conditions. Your doctor will likely recommend that you avoid taking this supplement during your Litfulo treatment.
  • Foods: Taking Litfulo with caffeinated foods or drinks could increase the risk of caffeine’s side effects, such as dizziness and headache. Caffeine is in coffees, teas, and various energy drinks. Your doctor may recommend that you limit caffeine intake during your Litfulo treatment.
  • Lab tests or vaccines: You should not receive live vaccines* during or just before starting your Litfulo treatment. Examples of live vaccines include measles, mumps, rubella (MMR), rotavirus, and chickenpox. If you need to receive a vaccine, talk with your doctor first to make sure it’s safe.

* Live vaccines contain weakened versions of the bacteria or virus that they’re meant to protect against.

Pregnancy and breastfeeding

It’s not known whether it’s safe to take Litfulo during pregnancy.

Tell your doctor immediately if you become pregnant while taking Litfulo. Also, consider enrolling in Litfulo’s pregnancy registry by calling 877-390-2940. By enrolling, you can help the drug’s manufacturer learn more about the drug’s use during pregnancy.

It isn’t known whether Litfulo is safe to take while breastfeeding. But the drug could possibly cause serious side effects in a child who is breastfed. Because of this, you should not breastfeed while taking Litfulo or for 14 hours after your last dose.

If you’re pregnant or breastfeeding or planning to become pregnant or to breastfeed, talk with your doctor before starting Litfulo treatment.

Boxed warnings

Litfulo has boxed warnings about the risks described below. A boxed warning is the most serious warning from the Food and Drug Administration (FDA) about drug effects that may be dangerous.

Boxed warnings for Litfulo include:

Risk of serious infections: Litfulo may increase your risk of developing serious infections. Examples include:

These infections can be fatal in rare cases. Symptoms of infection may include fever, chills, and tiredness.

Your doctor won’t prescribe Litfulo if you have a current infection. Your doctor will also likely have you stop taking Litfulo if you develop an infection during treatment. Once the infection is gone, your doctor may have you resume Litfulo treatment.

Your doctor will test you for TB before starting your Litfulo treatment. Your doctor will also monitor you for TB throughout your treatment.

Risk of cardiovascular problems: Litfulo belongs to a group of drugs called Janus kinase (JAK) inhibitors. When used for rheumatoid arthritis (RA), other JAK inhibitors may increase your risk of cardiovascular (heart and blood vessel) problems. Examples include heart attack, stroke, or death related to a cardiovascular problem.* Your risk may be further increased if you smoke or have smoked in the past.

Symptoms to watch for include chest tightness, feeling lightheaded, or slurring your words.

Litfulo is not approved to treat RA. But due to the risk of heart attack, stroke, or death with other JAK inhibitors, your doctor will likely not prescribe Litfulo if you’ve had a heart attack or stroke before.

Risk of blood clots: Litfulo may increase your risk of blood clots in your lungs, legs, or eyes. Due to these risks, your doctor may not prescribe Litfulo for you if you have an increased risk of blood clots.*

Symptoms to watch for include pain in your legs, chest, or eyes. If you experience these symptoms, your doctor will likely have you stop taking Litfulo until they can rule out blood clots as the cause.

Risk of cancer: Litfulo may increase your risk of developing certain cancers. These include lymphoma and certain types of skin and lung cancer. Your risk may be further increased if you smoke or have smoked in the past.

You and your doctor will weigh the benefits of taking Litfulo with its potential risks before starting your treatment, especially if you’ve had certain cancers before.

Increased risk of death: Litfulo belongs to a group of drugs called JAK inhibitors. When used for RA, other JAK inhibitors may increase your risk of death.*

Litfulo is not approved to treat RA. But due to the risk of death with other JAK inhibitors, you and your doctor will discuss the benefits and risks of Litfulo before you start treatment.

To learn more about these warnings, talk with your doctor.

* You have a higher risk if you’re age 50 years or older and have at least one risk factor for heart disease.

Other warnings

Litfulo can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Litfulo is a good treatment option for you.

Talk with your doctor about your health history before you take Litfulo. Be sure to tell them if any of the following factors apply to you:

*Live vaccines contain weakened versions of the bacteria or virus that they’re meant to protect against. Examples of live vaccines include measles, mumps, rubella (MMR), rotavirus, and chickenpox.

Other drugs are available that can treat your condition. If you’d like to explore an alternative to Litfulo, talk with your doctor. They can tell you about other medications that might work well for you.

Other drugs used to treat alopecia areata include:

  • other Janus kinase (JAK) inhibitors, such as baricitinib (Olumiant)
  • drugs that suppress your immune system, such as methotrexate (Trexall, Otrexup, others) or cyclosporine (Gengraf, Neoral, Sandimmune)
  • corticosteroids, such as prednisone (Rayos)

If you have questions about taking Litfulo, talk with your doctor or pharmacist. Questions you may want to ask include:

  • Can you recommend ways to lower my risk of infection while I take Litfulo?
  • If I use other drugs for alopecia along with Litfulo, will I see results faster?
  • What alternatives are available if I can’t afford Litfulo?

To learn more about Litfulo, see this article:

To get information on different conditions and tips for improving your health, subscribe to any of Healthline’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.

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.