Dosing & Uses


Dosage Forms & Strengths

injectable solution

  • 300mg/15mL

Multiple Sclerosis

Indicated as monotherapy for patients with relapsing forms of multiple sclerosis, including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease

300 mg IV infusion q4wk

When initiating and continuing treatment, consider whether expected benefit is sufficient to offset risk of PML

Crohn Disease

Indicated for moderate-to-severe Crohn disease in adults who had inadequate/intolerant response to conventional treatment and TNF-alpha inhibitors

300 mg IV q4wk

Dosing Considerations

Because natalizumab increases risk of progressive multifocal leukoencephalopathy (PML), it is recommended for patients who have had an inadequate response to, or are unable to tolerate, an alternate multiple sclerosis therapy

Additional or previous immunosuppressive therapy increases risk for PML; therefore, do not administer concomitantly with immunosuppressants (eg, 6-mercaptopurine, azathioprine, cyclosporine, or methotrexate) or TNF-alpha inhibitors

<18 years: Safety and efficacy not established



Interaction Checker

and natalizumab

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            Adverse Effects


            Fatigue (10%)

            Diarrhea (10%)

            Urinary urgency/frequency (9%)

            Sinusitis (8%)

            Vaginal infections (8%)

            Arthralgia (8%)

            Cough (3-7%)

            Viral infection (7%)

            Dermatitis (7%)

            Pharyngolaryngeal pain (6%)

            Peripheral edema (6%)

            Rash (6%)

            Dysmenorrhea (2-6%)

            Vertigo (6%)

            Dyspepsia (5%)

            Abnormal liver function test (5%)

            Irregular menstruation (5%)

            Urinary incontinence (4%)

            Toothache (4%)

            Pruritus (4%)

            Lower abdominal pain (4%)

            Constipation (4%)

            Vaginal infections (4%)

            Limb injury (3%)

            Viral infections (3%)

            Urinary tract infections (3%)

            Flatulence (3%)

            Skin laceration (2%)

            Aphthous stomatitis (2%)

            Amenorrhea (2%)

            Ovarian cyst (2%)

            Somnolence (2%)

            Acute hypersensitivity reactions (2%)

            Thermal burn (1%)

            Dry skin (1%)

            Tremor (1%)

            Night sweats (1%)

            Postmarketing Reports

            Hemolytic anemia



            Black Box Warnings

            Increased risk of progressive multifocal leukoencephalopathy, an opportunistic viral infection of the brain caused by the JC virus in immunocompromised patients that usually leads to death or severe disability

            Immune reconstitution inflammatory syndrome may occur in patients who have developed PML; IRIS is a rare condition characterized by severe inflammatory response

            Because of the risk of PML, natalizumab is available only through a special restricted distribution program; prescribers, infusion centers, and pharmacies associated with infusion centers registered with the program, are able to prescribe, distribute, or infuse the product to patients who are enrolled in and meet all the conditions of the TOUCH Prescribing Program

            Healthcare professionals should monitor patients on natalizumab for any new sign or symptom that may be suggestive of PML

            Withhold dose immediately at the first sign or symptom suggestive of PML

            For diagnosis, an evaluation that includes a gadolinium-enhanced MRI scan of the brain and, when indicated, cerebrospinal fluid analysis for JC viral DNA are recommended

            Consider assessing anti-JCV antibody status prior to treatment or during treatment if antibody status is unknown; the Stratify JCV Antibody ELISA test (Focus Diagnostics) was cleared by FDA on January 20, 2012

            Factors known to increase risk of PML in natalizumab-treated patients

            • Longer treatment duration, especially beyond 2 years
            • Prior treatment with an immunosuppressant (eg, mitoxantrone, azathioprine, methotrexate, cyclophosphamide, mycophenolate)
            • Presence of anti-JCV antibodies
            • Patients with all 3 known risk factors have an estimated risk of PML of 11/1,000
            • The risks and benefits of continuing treatment with natalizumab should be carefully considered in patients who are found to be anti-JCV antibody positive and have 1 or more additional risk factors
            • PML has been reported following discontinuation in patients who did not have findings suggestive of PML at the time of discontinuation; continue to monitor for any new signs or symptoms that may be suggestive of PML for ~6 months following discontinuation



            Active/history of progressive multifocal leukoencephalopathy


            Increased risk of PML with prolonged duration of therapy, prior treatment with immunosuppressants, or positive anti-JCV antibody status (see Black Box Warnings)

            Do not use with other immunosuppressives; may increase the risk for certain infections; monitor patients for development of infections

            Possibility of anaphylactic reaction; observe patients during and for 1 hr after infusion to see if symptoms of hypersensitivity-type reactions develop

            Increased risk of developing encephalitis and meningitis caused by HSV and VZV; serious, life-threatening, and sometimes fatal cases reported; discontinue therapy if this occurs and treat appropriately

            Severe hepatic injury reported as early as 6 days following therapy initiation, including markedly elevated LFTs and bilirubin; discontinue in patients with jaundice or with significant liver injury

            After plasma exchange, wait at least two weeks to test for anti-JCV antibodies to avoid false negative test results caused by the removal of serum antibodies; after infusion of intravenous immunoglobulin (IVIg), wait at least 6 months (5 half-lives) for the IVIg to clear in order to avoid false positive anti-JCV antibody test results


            Pregnancy & Lactation


            There are no adequate data on the developmental risk associated with use in pregnant women

            Animal data

            • In animal studies, administration of natalizumab during pregnancy produced fetal immunologic and hematologic effects in monkeys at doses similar to the human dose and reduced offspring survival in guinea pigs at doses greater than the human dose
            • Doses were not maternally toxic but produced the expected pharmacological effects in maternal animals


            Natalizumab has been detected in human milk

            No data available on the effects of this exposure on the breastfed infant or the effects of the drug on milk production

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.



            Mechanism of Action

            Recombinant humanized monoclonal antibody that binds to the α4-subunit of α4β1 and α4β7 integrins, prevents leukocyte-endothelial adhesion and leukocyte extravasation


            Peak plasma concentration: 64-132 mcg/mL


            Vd: 5.7 L (multiple sclerosis); 5.2L (Crohn disease)


            Half-Life: 7-15 days (multiple sclerosis); 3-17 days (Crohn disease)



            IV Compatibility

            0.9% NaCl

            IV Incompatibility H3

            No other IV diluents may be used to prepare diluted solution

            IV Preparation

            Concentrate is a colorless opalescent solution

            Visually inspect for particulate matter or discoloration - do not use if either present

            Withdraw 15 mL from the vial and dilute in 100 mL 0.9% NaCl; no other diluent should be used

            Gently invert to mix - do not shake

            Make sure no particulate matter is present

            After dilution, use immediately or within 8 hr (keep refrigerated at 2-8°C)

            If refrigerated, warm before using

            Do not freeze

            IV Administration

            Infuse over 1 hr

            After infusion is complete flush with 0.9% NaCl

            Do not coadminister any other drugs either through Y-site or dissolved in same solution

            Observe patients during infusion and for 1 hr after infusion is complete

            Promptly discontinue infusion upon any signs or symptoms consistent with a hypersensitivity-type reaction

            Use of filtration devices during administration has not been evaluated

            Other medications should not be injected into infusion set side ports or mixed with natalizumab


            Unopened vials: Refrigerate at 2-8°C (36-46°F); do not use beyond expiration date on the carton and vial label; do not freeze or shake; protect from light

            Diluted solution: Refrigerate at 2-8°C; use within 8 hr





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            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
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            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
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            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.