Tysabri is a brand-name intravenous (IV) infusion that’s prescribed for conditions such as multiple sclerosis (MS) and Crohn’s disease. Tysabri contains the active drug natalizumab, which is a biologic drug (made from living cells).

Tysabri is FDA-approved to treat the following conditions in adults:

* “Active” means that you currently have symptoms.

Drug details

You’ll find key information about Tysabri below.

  • Drug class: integrin receptor antagonists
  • Drug form: IV infusion that’s given by a healthcare professional at certain clinics or infusion centers
  • Generic or biosimilar available? No
  • Prescription required? Yes
  • Controlled substance? No
  • Year of FDA approval: 2004

Tysabri is available only as a brand-name medication. Tysabri contains one active drug ingredient: natalizumab.

Tysabri isn’t currently available as a biosimilar.

A biosimilar is a drug that’s similar to a brand-name medication. A generic drug, on the other hand, is an exact copy of a brand-name medication. Biosimilars are based on biologic drugs, which are made from parts of living organisms. Generics are based on regular drugs made from chemicals.

Both biosimilars and generics are as safe and effective as the brand-name drug they’re made to copy. They also tend to cost less than brand-name drugs.

Tysabri can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Tysabri. These lists do not include all possible side effects.

For more information on the possible side effects of Tysabri, talk with your doctor or pharmacist. They can give you tips on how to manage any side effects that may be bothersome.

More common side effects

The more common side effects of Tysabri can include:

  • headache
  • pain in your arms, legs, joints, or stomach
  • fatigue or feeling tired
  • diarrhea
  • nausea
  • rash
  • weight loss or weight gain

Most of these side effects may go away within a few days or a couple of weeks. If they’re more severe or don’t go away, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Tysabri aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects and their symptoms can include the following:

  • Progressive multifocal leukoencephalopathy (PML),* a type of severe brain infection. Symptoms can include:
    • gradually losing strength on one side of your body
    • clumsiness
    • vision problems
    • changes in your thinking, memory, or personality
    • confusion
  • Herpes infections, such as encephalitis (brain infection) or meningitis (brain and spinal cord infection). Symptoms can include:
    • sudden fever
    • severe headache
    • vision changes or eye pain
    • confusion
  • Liver damage. Symptoms can include:
    • jaundice (yellowish color of your skin and the whites of your eyes)
    • dark urine
    • nausea or vomiting
    • fatigue
  • Infections in your urinary tract, vagina, lungs, nose, or throat. General symptoms of an infection can include:
  • Low level of platelets.† Symptoms may include:
    • bruising or bleeding more easily than usual
    • petechiae (skin discoloration from bleeding under the skin)
  • Gallstones. Symptoms may include:
    • fever
    • nausea and vomiting
    • abdominal pain
  • Appendicitis (inflammation of the appendix). Symptoms may include:
    • abdominal pain that starts near the belly button
    • loss of appetite
    • nausea and vomiting
  • Allergic reactions. See “Side effect details” below for possible symptoms.
  • Depression. See “Side effect details” below for possible symptoms.

* Tysabri has a boxed warning for PML. This is the most serious warning from the Food and Drug Administration (FDA). For more information, see the “FDA warning” section at the beginning of this article.
† This side effect was reported in people using Tysabri after it was approved for use.

Side effect details

You may wonder how often certain side effects occur with this drug. Here’s some detail on some of the side effects this drug may cause. To learn more about side effects of Tysabri, see this article.

Allergic reaction

As with most drugs, some people can have an allergic reaction after taking Tysabri. One clinical trial looked at people with multiple sclerosis (MS) or clinically isolated syndrome (CIS). Of those people who received Tysabri, 4% had an allergic reaction within 2 hours of taking the drug. This was compared to less than 1% of people who took a placebo (a treatment without an active drug).

In the same study, 5% of people who received Tysabri had an allergic reaction more than 2 hours after they took the drug. This was compared to 2% of people who took a placebo.

In other clinical trials, 2% of people with Crohn’s disease had an allergic reaction within 2 hours of receiving Tysabri. This was compared to less than 1% of people who took a placebo. These studies didn’t include information on allergic reactions that occurred more than 2 hours after taking Tysabri.

Symptoms of a mild allergic reaction can include:

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:

  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your tongue, mouth, or throat
  • trouble breathing or wheezing
  • chest pain
  • nausea
  • dizziness
  • low blood pressure
  • chills

It’s possible to have a serious allergic reaction any time after you receive Tysabri. But these reactions typically occur within 2 hours of starting the dose. A healthcare professional will monitor you for at least an hour after you receive Tysabri. So if you have an allergic reaction during that time, they can treat it right away.

If you have a severe allergic reaction to Tysabri after you leave the healthcare professional, call your doctor right away. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Progressive multifocal leukoencephalopathy (PML)

Taking Tysabri increases your risk for a severe brain infection called progressive multifocal leukoencephalopathy (PML). This is a rare but very serious side effect. PML can lead to severe disability, such as being unable to walk. Sometimes, it may be fatal.

In a clinical trial, 2 out of 1,869 people who took Tysabri with Avonex (another MS drug) for MS or CIS developed PML. This was compared to zero people who took only Avonex.

In another clinical trial, 1 out of 1,043 people who took Tysabri for Crohn’s disease developed PML. This was compared to zero people who took a placebo (a treatment without an active drug).

It’s possible to develop PML during Tysabri treatment and up to 6 months after you stop taking the drug.

You’re at an increased risk for PML if you:

  • have the John Cunningham virus
  • have been taking Tysabri for longer than 2 years
  • had prior treatment with certain medications that may have lowered the activity of your immune system

While you take Tysabri, your doctor will monitor you for PML. If you have any symptoms of PML, tell your doctor right away. (See “Serious side effects” above for a list of possible symptoms.) Your doctor can decide if you should stop taking Tysabri. It’s not possible to prevent or cure PML.

Skin rash

While you take Tysabri, it’s possible that you may have a rash on your skin. In one clinical trial, 12% of people who took Tysabri for MS or CIS developed a skin rash. This was compared to 9% of people who took a placebo (a treatment without an active drug).

In another clinical trial, 6% of people who took Tysabri for Crohn’s disease developed a skin rash. This was compared to 4% of people who took a placebo.

If you’re taking Tysabri and develop a skin rash that doesn’t go away after a couple of days or gets worse, tell your doctor. They can recommend how to treat it.

Weight loss or weight gain

While you take Tysabri, it’s possible that you may lose weight or gain weight. In a clinical trial, 2% of people who took Tysabri for MS or CIS lost weight or gained weight. This was compared to less than 1% of people who took a placebo (a treatment without an active drug).

If you have any concerns about your weight loss or weight gain, talk with your doctor. They may adjust your diet and exercise routine as needed. Your doctor may also refer you to a dietitian to make sure you’re getting the nutrients you need.

Headache

While taking Tysabri, it’s possible that you may have headache. In a clinical trial, 38% of people who took Tysabri for MS or CIS had headache. This was compared to 33% of people who took a placebo (a treatment without an active drug)..

In two other clinical trials, 32% and 37% of people who took Tysabri for Crohn’s disease had headache. This was compared to 23% and 31% of people who took a placebo. Headache is one of the most common side effects of Tysabri.

If you experience headache that don’t go away while you take Tysabri, talk with your doctor. They can recommend treatments that may help.

Depression

While taking Tysabri, it’s possible that you may have depression. In a clinical trial, 19% of people who took Tysabri for MS or CIS developed depression. This was compared to 16% of people who took a placebo (a treatment without an active drug). Depression is one of the most common side effects of Tysabri.

If you’re taking Tysabri and have any symptoms of depression, tell your doctor. Symptoms may include feeling sad, hopeless, losing interest in activities you usually enjoy, or suicidal thoughts or behaviors. You and your doctor can discuss ways to manage your symptoms and which treatments are available. Your doctor may also have you stop taking Tysabri and use a different medication.

Suicide prevention

If you know someone at immediate risk of self-harm, suicide, or hurting another person:

  • Ask the tough question: “Are you considering suicide?”
  • Listen to the person without judgment.
  • Call 911 or the local emergency number, or text TALK to 741741 to communicate with a trained crisis counselor.
  • Stay with the person until professional help arrives.
  • Try to remove any weapons, medications, or other potentially harmful objects.

If you or someone you know is having thoughts of suicide, a prevention hotline can help. The 988 Suicide and Crisis Lifeline is available 24 hours a day at 988. During a crisis, people who are hard of hearing can use their preferred relay service or dial 711 then 988.

Find more links and local resources.

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Hair loss (not a side effect)

While taking Tysabri, it’s not likely that you’ll lose your hair. In clinical trials of Tysabri, hair loss wasn’t a side effect.

However, some other MS drugs, such as teriflunomide (Aubagio) and mitoxantrone, may cause hair loss.

And Crohn’s disease itself may cause some hair loss. This is because your stomach may not properly absorb the nutrients from your food that help your hair grow.

If you’re taking Tysabri and are concerned about hair loss, talk with your doctor. They may test you to see what’s causing the hair loss. Your doctor may also give you tips on how to cope with losing your hair.

Cancer (not a side effect)

Tysabri isn’t likely to cause you to develop cancer. In clinical trials of Tysabri, cancer wasn’t a side effect.

Research has found an increased risk of certain types of cancer in the intestines of people with Crohn’s disease.

And there’s conflicting information on whether MS increases the risk of cancer. More data is needed to confirm whether there’s a link between MS and cancer.

If you’re taking Tysabri and are concerned about developing cancer, talk with your doctor.

As with all medications, the cost of Tysabri can vary. The actual price you’ll pay depends on your insurance plan and your location.

Financial and insurance assistance

If you need financial support to pay for Tysabri, or if you need help understanding your insurance coverage, help is available.

Programs are available that offer financial and insurance assistance for Tysabri. These include the Biogen Copay Program, which could help lower the cost of your medication. For more information and to find out if you’re eligible for support, call 800-456-2255 or visit the drug manufacturer’s website.

The Food and Drug Administration (FDA) approves prescription drugs such as Tysabri to treat certain conditions.

Tysabri is a multiple sclerosis (MS) medication. It’s FDA-approved to treat:

MS is an illness in which your immune system (your body’s defense against disease) attacks your central nervous system. (Your brain and spinal cord make up your central nervous system.) With MS, your immune system destroys myelin, which is the covering that protects nerve fibers.

Without this covering, your brain has a hard time sending messages to the rest of your body through your nerves. This can lead to permanent nerve damage and trouble moving around.

With relapsing forms of MS, you have times when you have few or no symptoms. This is followed by relapses (flare-ups during which your symptoms get worse). Relapsing forms of MS are the most common types of MS. On the other hand, active SPMS is an advanced form of MS that doesn’t cause flare-ups or periods of remission. It causes symptoms to gradually worsen over time. Active SPMS typically develops from RRMS.

CIS is an episode of one or more symptoms that are similar to those caused by MS. This condition can be the first sign of MS. For more detailed information about MS and CIS, you can see our MS hub.

Tysabri helps slow down the worsening of MS symptoms. The drug also helps decrease the number of flare-ups you have.

Note: Additionally, Tysabri is approved to treat Crohn’s disease in adults. This use is described just below in the “Other uses” section.

Effectiveness for MS

One clinical trial looked at how Tysabri worked in people with MS or CIS. After 2 years of treatment, people who took Tysabri had a 42% lower risk of worsening symptoms than people who took a placebo (a treatment without an active drug). The worsening symptoms included trouble moving or walking. And 67% of people who took Tysabri didn’t relapse (have flare-ups), compared to 41% of people who took a placebo.

Another clinical trial looked at people with MS or CIS who took Tysabri and a second MS drug called Avonex. After 2 years of treatment, people who took Tysabri with Avonex had a 24% lower risk of their symptoms getting worse than people who took only Avonex. The worsening of symptoms included trouble moving or walking. And 54% of people who took both drugs didn’t relapse (have flare-ups), compared to 32% of people who took only Avonex.

In addition to multiple sclerosis (MS) and clinically isolated syndrome (CIS), the Food and Drug Administration (FDA) has approved Tysabri to treat some forms of Crohn’s disease.

Tysabri for Crohn’s disease

Tysabri can be used to treat moderately to severely active Crohn’s disease if other treatments haven’t worked for you. Crohn’s disease is a kind of inflammatory bowel disease in which you have swelling in your digestive tract. And “active” means that you currently have symptoms. For more information about Crohn’s disease, you can see our IBD hub.

Effectiveness for Crohn’s disease

One clinical trial looked at people with Crohn’s disease who took Tysabri. After 12 weeks of treatment, 60% of people had fewer symptoms (felt better). This was compared to 44% of people who took a placebo. And 37% of people were in remission, which means that they had fewer symptoms or none at all. This was compared to 25% of people who took a placebo.

Here are answers to some frequently asked questions about Tysabri.

Will I have withdrawal symptoms if I stop using Tysabri?

It’s not likely. There haven’t been any reports of withdrawal symptoms in people who stopped taking Tysabri.

Your symptoms of multiple sclerosis (MS), clinically isolated syndrome (CIS), or Crohn’s disease may worsen after stopping Tysabri.

If you’d like to stop taking Tysabri, first talk with your doctor. They can discuss with you how to best end your treatment. Your doctor can also recommend other ways to help manage your symptoms of MS, CIS, or Crohn’s disease.

Where can I get Tysabri infusions?

To receive Tysabri doses, you’ll have to go to a clinic or infusion center that’s certified through Tysabri Outreach: Unified Commitment to Health (TOUCH). TOUCH is a Risk Evaluation and Mitigation Strategies (REMS) prescribing program. This is due to the risk of progressive multifocal leukoencephalopathy (PML)* with Tysabri. Talk with your doctor to learn more about TOUCH Prescribing Program.

A healthcare professional will give you the drug as an intravenous (IV) infusion. This is an injection into your vein that drips in slowly over time. Tysabri infusions usually take an hour.

* Tysabri has a boxed warning for PML. This is the most serious warning from the Food and Drug Administration (FDA). For more information, see the “FDA warning” section at the beginning of this article.

Is Tysabri a chemotherapy drug or an immunosuppressant?

No, Tysabri isn’t a chemotherapy drug.

Instead, it’s an immunosuppressant. It may reduce the activity of your immune system (your body’s defense against disease).

When your immune system isn’t as strong as usual, it has a hard time fighting off germs. So Tysabri may also increase your risk of getting infections. These include:

To help prevent infections while you’re taking Tysabri, be sure to wash your hands often. Also, limit contact with anyone who’s sick. Avoid sharing personal items such as toothbrushes, drinking glasses, and towels with others.

If you develop an infection while taking Tysabri, tell your doctor right away. They can help treat it so it doesn’t get worse.

Can Tysabri be used to treat progressive MS?

Yes, the Food and Drug Administration (FDA) has approved Tysabri to treat active secondary progressive MS (SPMS) in adults. “Active” means you’re currently having symptoms. Tysabri is also FDA-approved to treat relapsing forms of MS, including relapsing-remitting MS (RRMS).

With relapsing forms of MS, you may have times when you have few or no symptoms (remission). This is followed by times when you have relapses (flare-ups during which your symptoms worsen).

But with progressive MS, including active SPMS, you’ll generally always have symptoms. Your MS tends to worsen, leading to more disability, such as having trouble moving or walking. Active SPMS typically develops from RRMS. See the “Tysabri for MS” section above for details.

If you have progressive MS, talk with your doctor. They can recommend the best treatment options for you.

Can I take Tysabri with steroids?

Maybe. If you have MS, CIS, or Crohn’s disease, you may already be taking a steroid as part of your treatment. Your doctor may prescribe Tysabri in addition to the steroid. Some people can keep taking the steroid during their Tysabri treatment.

However, taking Tysabri with certain steroids may increase your risk for serious infections. (To learn more about possible infections, see the “Tysabri side effects” section above.)

If you’re taking one of these steroids, your doctor will slowly taper your dosage within 6 months of you starting to take Tysabri. This means that you’ll take less and less of the steroid until you stop taking it completely. Some of these steroids include oral (taken by mouth) forms you use long term — for example, budesonide (Entocort EC, Uceris).

If you’re taking a steroid, talk with your doctor before you start taking Tysabri. They can go over your medications with you and recommend the best dosages.

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to suit your needs.

For more information about Tysabri’s dosage, refer to this article.

Drug forms and strengths

Tysabri comes in a 15-milliliter (mL) single-dose vial. Each vial contains 300 milligrams (mg) of the drug.

A healthcare professional will give you Tysabri as an intravenous (IV) infusion.

To receive Tysabri doses, you’ll have to go to a clinic or infusion center that’s certified through Tysabri Outreach: Unified Commitment to Health (TOUCH). TOUCH is a Risk Evaluation and Mitigation Strategies (REMS) prescribing program. This is due to the risk of progressive multifocal leukoencephalopathy (PML)* with Tysabri. Talk with your doctor to learn more about TOUCH Prescribing Program.

Infusion times for Tysabri are usually about an hour. After your infusion is complete, your healthcare professional will monitor you for at least 1 hour in case you have an allergic reaction.

* Tysabri has a boxed warning for PML. This is the most serious warning from the Food and Drug Administration (FDA). For more information, see the “FDA warning” section at the beginning of this article.

Dosage for multiple sclerosis (MS)

For multiple sclerosis (MS) and clinically isolated syndrome (CIS), the typical dose of Tysabri is 300 mg every 4 weeks.

Dosage for Crohn’s disease

For Crohn’s disease, the typical dose of Tysabri is 300 mg every 4 weeks.

What if I miss a dose?

If you miss an appointment to have an infusion, call your doctor right away. They can schedule a new visit and adjust the timing of other appointments if needed.

Will I need to use this drug long term?

Tysabri is meant to be used as a long-term treatment. If you and your doctor determine that Tysabri is safe and effective for you, you’ll likely take it long term.

Other drugs are available that can treat multiple sclerosis (MS), clinically isolated syndrome (CIS), and Crohn’s disease. Some may be better suited for you than others. If you’re interested in finding an alternative to Tysabri, talk with your doctor. They can tell you about other medications that may work well for you.

Alternatives for multiple sclerosis

Examples of other drugs that help treat MS or CIS include:

Alternatives for Crohn’s disease

Examples of other drugs that help treat Crohn’s disease include:

You may wonder how Tysabri compares with other medications that are prescribed for similar uses. Here we look at how Tysabri and Kesimpta are alike and different.

The Food and Drug Administration (FDA) has approved both Tysabri and Kesimpta to treat certain forms of multiple sclerosis (MS) and clinically isolated syndrome (CIS) in adults.

Tysabri contains the active drug natalizumab. Kesimpta contains the active drug ofatumumab.

These drugs are given in different ways. Tysabri is given as an intravenous (IV) infusion by a healthcare professional.* Kesimpta is self-injected subcutaneously using either a single-dose prefilled pen or a single-dose prefilled syringe.

Both Tysabri and Kesimpta have been found to be effective for relapsing forms of MS and CIS. Your doctor or pharmacist can provide more information about how these drugs compare.

* To learn more about how Tysabri is administered, see the “How Tysabri is given” section below.

You may wonder how Tysabri compares to other medications that are prescribed for similar uses. Here we look at how Tysabri and Ocrevus are alike and different.

Uses

The Food and Drug Administration (FDA) has approved both Tysabri and Ocrevus to treat certain forms of multiple sclerosis (MS) and clinically isolated syndrome (CIS) in adults.

Tysabri is also approved to treat moderately to severely active Crohn’s disease in adults if other treatments haven’t worked. Crohn’s disease is a kind of inflammatory bowel disease in which you have swelling in your digestive tract. And “active” means that you currently have symptoms.

Tysabri contains the active drug natalizumab. Ocrevus contains the active drug ocrelizumab.

Drug forms and administration

Tysabri and Ocrevus are both given as an intravenous (IV) infusion by a healthcare professional. They will monitor you for at least 1 hour after the treatment in case you have an allergic reaction.

* To learn more about how Tysabri is administered, see the “How Tysabri is given” section below.

Side effects and risks

Tysabri and Ocrevus contain different drugs but are in a similar drug class. (A class of drugs is a group of medications that work in a similar way.) Therefore, both medications can cause very similar side effects. Below are examples of these side effects.

More common side effects

These lists contain examples of more common side effects that can occur with Tysabri, with Ocrevus, or with both drugs (when taken individually).

  • Can occur with Tysabri:
    • pain in your arms, legs, joints, or stomach
    • diarrhea
    • weight loss or weight gain
    • nausea
    • rash
    • fatigue or or feeling tired
  • Can occur with Ocrevus:
    • fever
    • faster heart rate
  • Can occur with both Tysabri and Ocrevus:

Serious side effects

These lists contain examples of serious side effects that can occur with Tysabri, with Ocrevus, or with both drugs (when taken individually).

* Tysabri has a boxed warning for PML. This is the most serious warning from the Food and Drug Administration (FDA). For more information, see the “FDA warning” section at the beginning of this article.

Effectiveness

Tysabri and Ocrevus have some different FDA-approved uses, but they’re both used to treat certain forms of MS and CIS in adults.

Separate studies in a larger review of studies compared the two drugs. Researchers found both Tysabri and Ocrevus to be effective for treating certain forms of MS.

Costs

Tysabri and Ocrevus are both brand-name drugs. There are currently no biosimilar forms of either drug. (A biosimilar is like a generic drug. It’s an exact copy of the active ingredient in a brand-name biologic drug. As with generics, biosimilars tend to cost less than the brand-name drug they’re based on.)

Tysabri generally costs less than Ocrevus. The actual price you’ll pay for either drug will depend on your insurance plan and your location.

A healthcare professional will give you Tysabri as an intravenous (IV) infusion in a clinic or your doctor’s office.

The healthcare professional will first put a needle into one of your veins. Then they’ll connect a bag that contains Tysabri to the needle. The drug will flow from the bag to your body. Tysabri infusion times usually last for an hour.

After your infusion is complete, the healthcare professional will monitor you for at least 1 hour in case you have an allergic reaction.

To receive Tysabri doses, you’ll have to go to a clinic or infusion center that’s certified through Tysabri Outreach: Unified Commitment to Health (TOUCH). TOUCH is a Risk Evaluation and Mitigation Strategies (REMS) prescribing program. This is due to the risk of progressive multifocal leukoencephalopathy (PML)* with Tysabri. Talk with your doctor to learn more about TOUCH Prescribing Program.

* Tysabri has a boxed warning for PML. This is the most serious warning from the Food and Drug Administration (FDA). For more information, see the “FDA warning” section at the beginning of this article.

How often it’s given

For multiple sclerosis (MS), clinically isolated syndrome (CIS), and Crohn’s disease, you’ll receive infusions of Tysabri every 4 weeks.

To help you remember when you have an appointment for an infusion, put your treatment schedule on a calendar. Also, set a reminder in your phone so that you don’t miss getting a dose of Tysabri.

There isn’t enough data to know whether it’s safe to take Tysabri during pregnancy.

There have been reports of low platelet levels and anemia (low red blood cell levels) in newborns exposed to Tysabri during pregnancy. Having low platelets means your blood isn’t able to clot as it should. Anemia can also cause symptoms such as fatigue or a fast or irregular heart rate. These conditions can be mild or serious in newborns.

If you take Tysabri while pregnant, be sure to talk about this with your doctor. They may recommend a complete blood count (CBC) test for your child after birth to check for low platelets and anemia. If needed, these conditions can be treated with an infusion.

Some animal studies have shown that Tysabri harmed the fetus. However, other animal studies showed that Tysabri didn’t cause any harm to the mother or fetus. Keep in mind that animal studies don’t always predict what will happen in humans.

If you’re pregnant or planning to become pregnant, tell your doctor before you start taking Tysabri. They can discuss the pros and cons of Tysabri treatment during pregnancy with you.

Clinical trials show that Tysabri passes into breast milk. However, there haven’t been any studies on whether Tysabri affects children exposed to the drug through breast milk.

If you breastfeed or you’re planning to breastfeed while taking Tysabri, talk with your doctor. They can discuss the possible risks and benefits with you.

Clinical studies haven’t shown that alcohol interacts with Tysabri.

However, if you drink alcohol, talk with your doctor. They can tell you how much alcohol, if any, is safe for you during your Tysabri treatment.

Tysabri can interact with several other medications.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe.

Tysabri and other medications

Below is a list of medications that can interact with Tysabri. This list does not contain all drugs that may interact with Tysabri.

Before taking Tysabri, 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, ask your doctor or pharmacist.

Tysabri and immunosuppressants

Tysabri is an immunosuppressant drug. Immunosuppressants reduce the activity of your immune system. (Your immune system helps your body fight disease.) When your immune system isn’t strong, it has a hard time fighting off germs.

If you have multiple sclerosis (MS), clinically isolated syndrome, or Crohn’s disease, you may already be taking an immunosuppressant. Taking Tysabri with another immunosuppressant may increase your risk for serious infections. (To learn more about possible infections, see the “Tysabri side effects” section above.)

Examples of immunosuppressant drugs that may increase your risk for infections include:

If you’re taking an immunosuppressant, talk with your doctor before you start receiving Tysabri. Your doctor may have you stop taking the immunosuppressant.

Tysabri and certain steroids

Taking Tysabri with certain oral steroids long term may increase your risk for infections. Tysabri and certain steroids may reduce the activity of your immune system (your body’s defense against disease). When your immune system isn’t strong, it has a hard time fighting germs. So taking these drugs together may make you more likely to develop an infection. (To learn more about possible infections, see the “Tysabri side effects” section above.)

An example of a steroid that may increase your risk for infections is budesonide (Entocort EC, Uceris).

If you’re using a steroid, talk with your doctor before you start receiving Tysabri. They may have you take less and less of the steroid until you stop using it completely. They can also recommend other ways to help manage your symptoms.

Tysabri and herbs and supplements

No herbs or supplements have been reported to interact with Tysabri. However, you should still check with your doctor or pharmacist before using any of these products.

In addition to Ocrevus (see above), other medications similar to Tysabri are also available. Here we look at how Tysabri and Humira are alike and different.

Uses

The Food and Drug Administration (FDA) has approved both Tysabri and Humira to treat moderately to severely active Crohn’s disease in adults if other treatments haven’t worked. Crohn’s disease is a kind of inflammatory bowel disease in which you have swelling in your digestive tract. And “active” means that you currently have symptoms.

Tysabri is also approved to treat certain forms of multiple sclerosis and clinically isolated syndrome in adults.

Humira is also approved to treat:

  • Crohn’s disease in children ages 6 years and older if other drugs haven’t worked
  • rheumatoid arthritis
  • psoriatic arthritis
  • moderate to severe juvenile idiopathic arthritis in those ages 2 years and older
  • ankylosing spondylitis (arthritis of the spine)
  • moderate to severe plaque psoriasis
  • moderate to severely active ulcerative colitis if other drugs haven’t worked, in adults and children ages 5 years and older
  • some types of noninfectious uveitis, including intermediate uveitis, posterior uveitis, and panuveitis in adults and children ages 2 years and older
  • hidradenitis suppurativa in adults and children ages 12 years and older

Tysabri contains the active drug natalizumab. Humira contains the active drug adalimumab.

Drug forms and administration

Tysabri is given as an intravenous (IV) infusion by a healthcare professional. They will monitor you for at least 1 hour after the treatment in case you have an allergic reaction.

Humira is given as an injection just under your skin (subcutaneous).

Side effects and risks

Tysabri and Humira contain different drugs but are in a similar drug class. (A class of drugs is a group of medications that work in a similar way.) Therefore, both medications can cause very similar side effects. Below are examples of these side effects.

More common side effects

These lists contain examples of more common side effects that can occur with Tysabri, with Humira, or with both drugs (when taken individually).

  • Can occur with Tysabri:
    • pain in your arms, legs, joints, or stomach
    • diarrhea
    • fatigue or feeling tired
    • weight loss or weight gain
  • Can occur with Humira:
    • few unique common side effects
  • Can occur with both Tysabri and Humira:
    • headache
    • rash
    • minor allergic reactions
    • nausea

Serious side effects

These lists contain examples of serious side effects that can occur with Tysabri, with Humira, or with both drugs (when taken individually).

* Tysabri has a boxed warning for PML. This is the most serious warning from the Food and Drug Administration (FDA). For more information, see the “FDA warning” section at the beginning of this article.
† Humira has a boxed warning for serious infection and cancer. For information, view the drug’s prescribing information.

Effectiveness

Tysabri and Humira have some different FDA-approved uses, but they’re both used to treat Crohn’s disease.

These drugs haven’t been directly compared in clinical trials. However, clinical trials have found both Tysabri and Humira to be effective for treating Crohn’s disease.

Costs

Tysabri and Humira are both brand-name drugs. There are currently no biosimilars for Tysabri. There are nine biosimilars for Humira: Hulio, Abrilada, Hadlima, Hyrimoz, Cyltezo, Amjevita, Idacio, Yuflyma, and Yusimry. They may cost less than Humira and Tysabri.

A biosimilar is a drug that’s similar to a brand-name medication. A generic drug, on the other hand, is an exact copy of a brand-name medication. Biosimilars are based on biologic drugs, which are made from parts of living organisms. Generics are based on regular drugs made from chemicals.

Both biosimilars and generics are as safe and effective as the brand-name drug they’re trying to copy. They also tend to cost less than brand-name drugs.

Tysabri generally costs more than Humira. The actual price you’ll pay for either drug will depend on your insurance plan and your location.

Tysabri contains the drug natalizumab, which belongs to the drug class called integrin receptor antagonists.

Tysabri is approved to treat certain forms of multiple sclerosis (MS), clinically isolated syndrome (CIS), and Crohn’s disease. To learn how Tysabri works to treat these conditions, see this article.

This drug comes with several precautions.

FDA warning: Progressive multifocal leukoencephalopathy (PML)

This drug has a boxed warning. This is the most serious warning from the Food and Drug Administration (FDA). A boxed warning alerts doctors and patients about drug effects that may be dangerous.

Taking Tysabri increases your risk for a severe brain infection called progressive multifocal leukoencephalopathy (PML). PML can lead to severe disability, such as not being able to walk. In some cases, it may be fatal. While you take Tysabri, your doctor will monitor you. If you have any signs or symptoms of the infection, your doctor may have you stop taking Tysabri. You also shouldn’t take Tysabri if you’ve had PML in the past.

Due to the risk of PML, you can only receive Tysabri doses through a drug safety program called Risk Evaluation and Mitigation Strategies (REMS). The REMS program for Tysabri is called Tysabri Outreach: Unified Commitment to Health (TOUCH). The program helps make sure that you know about possible side effects of the drug. If you have questions about the program, ask your doctor.

Other warnings

Before taking Tysabri, talk with your doctor about your health history. Tysabri may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Conditions that can reduce your immune system’s activity. Tysabri can reduce the activity of your immune system (your body’s defense against disease). So if you already have reduced immune system activity, your body may be less able to fight germs. Conditions that can reduce your immune system activity include a current infection, lymphoma, leukemia, and HIV. If you have any of these conditions, your doctor may prescribe a drug other than Tysabri.
  • Allergic reactions. Tysabri may cause mild or severe allergic reactions. If you have an allergic reaction to Tysabri, your doctor may have you stop taking the drug. They can also recommend a different treatment.
  • Pregnancy. It’s not known whether Tysabri is safe for you and your child during pregnancy. For more information, see the “Tysabri and pregnancy” section above.
  • Breastfeeding. It’s not known whether Tysabri is safe to take while breastfeeding. For more information, see the “Tysabri and breastfeeding” section above.

Note: For more information about the potential negative effects of Tysabri, see the “Tysabri side effects” section above.

The following information is provided for clinicians and other healthcare professionals.

Indications

Tysabri is indicated to treat certain forms of multiple sclerosis (MS) and clinically isolated syndrome (CIS). It is also indicated to treat Crohn’s disease and maintain remission when traditional therapies do not work.

Mechanism of action

Tysabri contains natalizumab, which is a monoclonal antibody that binds to alpha-4 integrin. In MS, it prevents the movement of T-lymphocytes into the central nervous system to reduce relapse frequency. In Crohn’s disease, Tysabri prevents leukocytes from migrating into the gut, thereby reducing inflammation.

Pharmacokinetics and metabolism

Tysabri contains natalizumab, which is a monoclonal antibody. The half-life is 7–15 days for MS, and 3–17 days for Crohn’s disease.

After every 4 weeks of dosing, it takes about 24 weeks for MS and 16–24 weeks for Crohn’s disease to reach a steady state.

Contraindications

Tysabri is contraindicated in people who have previously had:

Storage

Store Tysabri (single-dose vials and diluted solution) in the refrigerator between 36°F to 46°F (2°C to 8°C) and do not freeze. (Once diluted for administration, use the diluted solution right away, or store refrigerated and use within 8 hours.) Protect from light and do not shake.

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.

Tysabri Images