Tysabri (natalizumab) treats relapsing forms of multiple sclerosis (MS) and moderate-to-severe Crohn's disease (CD) in adults. This medication is a monoclonal antibody that works as an integrin antagonist. It lowers the immune system's activity and lessens inflammation. Tysabri (natalizumab) is given by a healthcare professional as a once-monthly infusion through the vein (IV). Common side effects include headache and fatigue. Because of the risk for serious infection, your care team will help you enroll in the TOUCH Prescribing Program and review the medication's warnings before treatment starts.
Relapsing forms of multiple sclerosis (MS)
Moderate-to-severe Crohn's disease (CD) when other treatments haven't worked well
Tysabri (natalizumab) is an integrin antagonist. It's a type of monoclonal antibody.
It's not completely known how Tysabri (natalizumab) works to treat MS and CD. But it's thought to work by attaching to a protein on immune cells called integrin. As a consequence, it blocks signals in your body that cause inflammation. This helps block inflammation from affecting your nerves (for MS) or your gut (for CD).
Source: DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor or nurse immediately if any of the following side effects occur:
More common
Bladder pain
blistering, crusting, irritation, itching, or reddening of the skin
bloody or cloudy urine
body produces substance that can bind to drug making it less effective or cause side effects
difficult, burning, or painful urination
difficulty with swallowing
dizziness
fast heartbeat
frequent, strong, or increased urge to urinate
itching of the vagina or genital area
lower back or side pain
pain during sexual intercourse
passing urine more often
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
thick, white vaginal discharge with no odor or with a mild odor
tightness in the chest
unusual tiredness or weakness
Rare
Blurred vision
changes in behavior
confusion
difficult or labored breathing
fainting or lightheadedness when getting up suddenly from a lying or sitting position
feeling of warmth
feeling unusually cold
gaseous abdominal or stomach pain
redness of the face, neck, arms, and occasionally, upper chest
shivering
stomach fullness
sweating
thoughts of killing oneself
yellow eyes or skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Cracked, dry, scaly skin
difficulty with moving
discouragement
feeling sad or empty
irritability
loss of interest or pleasure
muscle pain or stiffness
pain, cramps, or heavy bleeding
pain in the joints
stomach soreness or discomfort
swollen glands
trouble concentrating
trouble sleeping
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Infusions are once every month
Can be used for CD or MS
Has a risk monitoring program that anyone who prescribes, dispenses, infuses, or receives the medication must enroll in to make sure it's safe for you
Must be given by a healthcare professional in a healthcare setting
Infusions take about an hour
Raises your risk for serious infection
Only FDA approved for adults
When you first start Tysabri (natalizumab), you'll have an appointment with your prescriber every 3 months. After you've been taking this medication for some time, you'll only need to check in every 6 months. Tysabri (natalizumab) raises the risk for serious infections because it weakens your immune system. These follow-up visits help check for any infections that might've developed during treatment.
Get medical help right away if you don't feel well or if you have weakness on one side of the body, changes in personality, changes in vision, fever, cough, difficulty breathing, or diarrhea. These can be signs of a serious or life-threatening infection.
Share a list with your care team of all the medications you're taking or have recently taken. It's recommended to avoid other medications that weaken your immune system (like corticosteroids and TNF blockers). These medications can raise your risk for serious infections even more. Ask your care team if you have any questions about taking Tysabri (natalizumab) with other medications.
Tell your prescriber if you're currently taking any corticosteroids (also known as steroids). Both steroids and Tysabri (natalizumab) can weaken the immune system and put you at risk for serious infections. Your prescriber will discuss with you whether to slowly lower your steroid dose over time and stop the steroid medication or stop Tysabri (natalizumab) to lower your risk for infection.
You can get a serious infection even after you stop taking Tysabri (natalizumab). This is because it'll take some time for your immune system to bounce back and get stronger after you stop treatment. Continue to look out for signs of infection for at least 6 months after your treatment ends.
If you're pregnant or thinking of becoming pregnant, talk to your prescriber to see whether Tysabri (natalizumab) is right for you. The evidence isn't completely clear. But current research suggests that there might not be a link between a higher risk of harm to an unborn baby and taking the medication during pregnancy. Discuss with your prescriber about the risks and benefits of taking the medication while pregnant.
Don't breastfeed while you're taking Tysabri (natalizumab) unless you've talked to your prescriber. It's not known whether breastfeeding during treatment is safe for you and your baby. Research suggests that it's expected to be safe, but you might need to wait for a certain amount of time after giving birth to breastfeed.
Tysabri (natalizumab) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Having antibodies against the JC virus in the body | Taking Tysabri (natalizumab) for a long time (longer than 2 years) | Taking or have taken medications that weaken your immune system
Tysabri (natalizumab) can make it harder for your body to fight off infections. In particular, it can raise your risk of developing a serious brain infection caused by the John Cummingham virus (JCV). This infection is called progressive multifocal leukoencephalopathy (PML). It can lead to death or severe disability in people with a weakened immune system, like those who take Tysabri (natalizumab).
Get medical attention as soon as possible if you feel weak on one side of the body; feel clumsy; or notice changes in personality, vision, memory, or thinking skills. Continue to watch for these symptoms of PML for at least 6 more months after you stop taking Tysabri (natalizumab) because the infection can also appear after treatment ends. It's important to get help right away and get tested for PML since symptoms can worsen over days to weeks.
Because of the risk for PML with Tysabri (natalizumab), you, your prescriber, and any place that dispenses or infuses the medication must be enrolled in the TOUCH Prescribing Program. This is a Risk Evaluation and Mitigation Strategies (REMS) program that makes sure that everyone involved in treatment is aware of the risks of the medication.
Risk factors: Taking medications that weaken your immune system | Having a medical condition that weakens your immune system
Tysabri (natalizumab) can raise your risk for other infections caused by bacteria, viruses, or fungi. These infections can sometimes be serious. They can happen in different parts of your body, including the brain, eyes, lungs, stomach, and urinary tract. Let your care team know if you don't feel well or if you have any signs of an infection, like fevers, chills, tiredness, confusion, stomach aches, difficulty breathing, cough, or eye pain. If you get a serious infection while you're taking Tysabri (natalizumab), you might have to stop the medication so you can get appropriate treatment.
Some people taking Tysabri (natalizumab) developed liver damage. Sometimes, this led to life-threatening liver failure or the need for a transplant. Get medical attention right away if you feel tired or if you have poor appetite, discomfort in the upper right side of the stomach, dark urine, or yellowing of the skin or whites of your eyes. These can be symptoms of liver damage. Your prescriber might order blood tests to check your liver health. If you develop liver problems, you might need to stop Tysabri (natalizumab) to prevent more damage.
Risk factors: Having antibodies to Tysabri (natalizumab) in the body | Restarting Tysabri (natalizumab) after a long break
Allergic reactions, including infusion reactions, are possible while you're taking Tysabri (natalizumab). In rare cases, the allergic reaction can be very serious and sometimes life-threatening, like with anaphylaxis. The risk for allergic reactions might be higher if your body has made antibodies against the medication. Your prescriber might order blood tests every few months to check for these antibodies.
Allergic reactions can typically happen within 2 hours after the Tysabri (natalizumab) infusion starts. The healthcare professional will watch out for reactions during your infusion and also for a period of time afterwards.
Still, it's important to be aware of symptoms of an allergic reaction or an infusion reaction. These can include hives, rash, itching, dizziness, fever, shivering, flushing, shortness of breath, chest pain, and nausea. Get medical help right away if any of these symptoms appear. The healthcare professional will stop the infusion and help manage your symptoms. It's possible that you might need to stop taking Tysabri (natalizumab) altogether.
Some people who took Tysabri (natalizumab) developed low platelet levels during treatment. Platelets are cells in your blood that help stop bleeding when you get injured, like when you get a cut. Having platelet levels that are too low can put you at risk for bleeding.
Contact your care team right away if you notice any bleeding that's difficult to stop, easy bruising, or red or purple pinpoint spots on your skin. Your care team can examine you. You might need to stop Tysabri (natalizumab) if your platelet levels are too low.
The typical dose is 300 mg infused into the vein (IV) once per month. The IV infusion is given by a healthcare professional at a medical office, hospital, or infusion center.
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Currently have or have had progressive multifocal leukoencephalopathy (a type of viral infection in the brain)
Relapsing forms of multiple sclerosis (MS)
Moderate-to-severe Crohn's disease (CD) when other treatments haven't worked well
Relapsing forms of multiple sclerosis (MS)
Moderate-to-severe Crohn's disease
Moderate-to-severe rheumatoid arthritis (RA)
Moderate-to-severe plaque psoriasis (PsO)
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American Cancer Society. (2019). How is chemotherapy use to treat cancer?
Biogen. (n.d.). The Touch Prescribing Program.
Biogen. (2023). Overview of the TOUCH Program.
Biogen Inc. (2024). Tysabri- natalizumab injection [package insert]. DailyMed.
Butzkueven, H., et al. (2020). Long-term safety and effectiveness of natalizumab treatment in clinical practice: 10 years of real-world data from the Tysabri Observational Program (TOP). Journal of Neurology, Neurosurgery, and Psychiatry.
Drugs and Lactation Database (LactMed®). (2024). Natalizumab. National Institute of Child Health and Human Development.
Friend, S., et al. (2016). Evaluation of pregnancy outcomes from the Tysabri® (natalizumab) pregnancy exposure registry: A global, observational, follow-up study. BioMed Central Neurology.
Kawamoto, E., et al. (2012). Anti-integrin therapy for multiple sclerosis. Autoimmune Diseases.
McLean, L. P., et al. (2016). Integrin antagonists as potential therapeutic options for the treatment of Crohn's disease. Expert Opinion on Investigational Drugs.
National Human Genome Research Institute. (2024). Antibody.
National Institute of Neurological Disorders and Stroke. (2024). Progressive multifocal leukoencephalopathy.
Sandoz Inc. (2023). Tyruko (natalizumab-sztu) injection, for intravenous use [package insert].
Selewski, D. T., et al. (2010). Natalizumab (Tysabri). American Journal of Neuroradiology.
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