Ocrevus (Ocrelizumab) - Intravenous

What Is Ocrevus?

Ocrevus (ocrelizumab) is a prescription medication used to treat multiple sclerosis (MS).  It is administered via intravenous (IV) infusion at an infusion center, healthcare provider’s office, or home. Ocrevus belongs to a class of medications called monoclonal antibodies.

Ocrevus works by targeting and destroying certain B cells, which are cells that play a role in the immune system. In MS, these B cells attack the body’s nerves and cause inflammation. By removing these cells, Ocrevus diminishes their autoimmune attack.

Drug Facts

Generic Name: Ocrelizumab

Brand Name(s): Ocrevus

Drug Availability: Prescription

Therapeutic Classification: Immune modulator

Available Generically: No

Controlled Substance: N/A

Administration Route: Intravenous

Active Ingredient: Ocrelizumab

Dosage Form(s): Solution via IV infusion

What Is Ocrevus Used For?

Ocrevus is used to treat adults with relapsing forms of multiple sclerosis (MS), including clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease. It is also approved to treat primary progressive MS.

Ocrevus ( Ocrelizumab ) Drug Information - Front of person and showing the areas affected

Verywell / Zoe Hansen

How to Take Ocrevus

Taking certain medications before receiving Ocrevus helps prevent side effects. Typically, an antihistamine (like Benadryl) and corticosteroid (like dexamethasone) are given as premedications 30 to 60 minutes before the infusion of Ocrevus begins. Then, a 300-milligram (mg) infusion of Ocrevus is given, followed by another 300-milligram infusion two weeks later.  After these initial doses, a 600-milligram infusion is given once every six months. You will receive the infusion over a two-hour period or longer each time.


Ocrevus is stored under refrigeration. Medical personnel prepare the medication by diluting the solution in a bag of normal saline. Just before administration, the infusion bag is brought to room temperature.

How Long Does Ocrevus Take to Work?

Studies have shown that Ocrevus can have some effect at reducing MS progression within 12 weeks, but it may take six months or longer to achieve full effect.

What Are the Side Effects of Ocrevus?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the Food and Drug Administration (FDA) at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

The most common side effects of Ocrevus are:

Severe Side Effects

Severe side effects associated with Ocrevus are not uncommon. However, you will be monitored by a healthcare worker before and after your infusion. Reactions are possible up to 24 hours after the injection, so make sure you immediately contact your healthcare provider if you experience any of the following severe side effects:

Long-Term Side Effects

Although still being studied, long-term use of Ocrevus may be associated with an increased risk of breast cancer in women receiving Ocrevus. Speak to your healthcare provider about any family history of cancer before beginning treatment.

Report Side Effects

Ocrevus may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Ocrevus Should I Take?

A healthcare provider will administer Ocrevus intravenously (in the vein) either at an infusion center, healthcare provider's office, or your home, as follows:

  • An initial dose of 300 milligrams, followed by a second 300-milligram IV infusion two weeks later
  • Subsequent doses of single 600-milligram IV infusions every six months

A healthcare provider will monitor you closely for at least one hour after receiving the infusion to watch for severe reactions.


During treatment, your healthcare provider may decrease the infusion rate if you experience mild side effects. If you experience severe side effects, your healthcare provider may stop the infusion until all side effects have been resolved and then infuse at a slower rate. Any life-threatening infusion side effects will result in immediate and permanent discontinuation of Ocrevus.

Treatment with Ocrevus may be delayed if you have any active infection. 

Missed Dose

Doses are administered every six months, except for the first two doses. Make sure that your infusion is scheduled appropriately. If you miss an appointment, contact your healthcare provider as soon as possible for further assistance on how to resume Ocrevus. Do not wait until the next scheduled infusion.

Overdose: What Happens If I Take Too Much Ocrevus?

Ocrevus is administered by trained healthcare providers. At this time, no overdose information exists for Ocrevus. It is anticipated that an overdose of Ocrevus would mimic the severe side effects listed in the above section.


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It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly. Blood and urine tests may be needed to check for any unwanted effects.

This medicine may cause a rare but serious type of an allergic reaction called an infusion reaction. This can be life-threatening and requires immediate medical attention. Tell your doctor right away if you start to have a cough, difficulty with swallowing, sore throat, dizziness, headache, nausea, fast heartbeat, trouble breathing, chest tightness, swelling in your face or hands, fever, chills, skin itching, redness, rash, or hives, lightheadedness or faintness, or unusual tiredness or weakness while you are receiving this medicine.

Receiving this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant during treatment with this medicine and for 6 months after the last dose. If you think you have become pregnant while receiving this medicine, tell your doctor right away.

This medicine may increase your risk of developing infections. Avoid being near people who are sick or have infections while you are using this medicine. Wash your hands often. Also tell your doctor if you have ever had an infection that would not go away or an infection that kept coming back.

Check with your doctor right away if you have ear congestion, chills, cough, chest tightness, fever, sneezing, sore throat, body aches or pain, headache, loss of voice, runny or stuffy nose, unusual tiredness or weakness, or trouble breathing. These could be symptoms of a lung infection.

This medicine may increase your risk for herpes infection. Tell your doctor right away if you have a fever, blistering, burning, crusting, irritation, itching, reddening, stinging, or swelling of the skin, painful cold sores, or blisters on the lips, nose, eyes, genitals, or trunk of the body, skin rash, pain, or itching, changes in vision, confusion, eye pain or redness, headache, or stiff neck.

Check with your doctor if you have weakness on one side of the body, clumsiness, blurred vision, changes in thinking, memory problems, confusion, or personality changes. These could be symptoms of a serious and rare brain infection called progressive multifocal leukoencephalopathy (PML).

This medicine may cause hepatitis B virus reactivation. Tell your doctor right away if you have any symptoms of liver problems, such as yellow skin or eyes, dark brown-colored urine, right-sided stomach pain, fever, or severe tiredness.

While you are being treated with ocrelizumab, and after you stop treatment with it, do not have any immunizations (vaccinations) without your doctor's approval. You may receive live or live-attenuated vaccines at least 4 weeks or non-live vaccines at least 2 weeks before starting this medicine. Ocrelizumab may lower your body's resistance and there is a chance you might get the infection the immunization is meant to prevent. In addition, other persons living in your household should not take oral polio vaccine since there is a chance they could pass the polio virus on to you. Also, avoid persons who have taken oral polio vaccine within the last several months. Do not get close to them, and do not stay in the same room with them for very long. If you cannot take these precautions, you should consider wearing a protective face mask that covers the nose and mouth.

Using this medicine may increase your risk of getting cancer (eg, breast cancer). Talk to your doctor if you have concerns about this risk.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Ocrevus?

You should not receive Ocrevus if you:

  • Have received any live vaccines, such as measles, mumps, rubella (MMR), rotavirus, chickenpox, and yellow fever vaccines, less than four weeks before starting treatment.
  • Have received non-live vaccines, such as the flu, shingles, hepatitis B, and pneumococcal vaccines, less than two weeks before starting treatment.
  • Have an active infection
  • Have a history of cancer or HBV infection and have not been screened for active infection

If you have an active HBV infection, your healthcare provider will not prescribe you this medication. This is because Ocrevus works on the immune system and latent HBV can reactivate, even in the case of a previously resolved infection. This means the HBV that has been successfully treated in the past may return.

What Other Medications Interact With Ocrevus?

Live vaccines may interact with Ocrevus and should not be administered while receiving Ocrevus.  All live vaccines should be completed at least four weeks prior to initiating treatment with Ocrevus.  

What Medications Are Similar?

Drugs that are similar to Ocrevus include:

  • Kesimpta (ofatumumab): Self-administered injection once a month
  • Tysabri (natalizumab): Infusion every four weeks
  • Lemtrada (alemtuzumab): Infusion is given five days in a row, then three days in a row a year later
  • Copaxone (glatiramer acetate): Injection under the skin three times a week

This is a list of drugs also prescribed for the targeted condition(s). It is NOT a list of drugs recommended to take with Ocrevus. In fact, you should not take these drugs together. Ask your pharmacist or a healthcare provider if you have questions.

Frequently Asked Questions

  • Can I receive vaccinations while on Ocrevus?

    Certain types of vaccines should generally not be received when on Ocrevus. The best course of action is to speak with your healthcare provider about potential vaccines that you may need before starting treatment.

  • Why do I require premedication for my Ocrevus infusion?

    Ocrevus, like other medications in the same class, has a relatively high incidence of infusion reactions which can range from uncomfortable to life-threatening. Premedication prior to infusion can help prevent, lessen, and reduce these potential reactions. Typically, an antihistamine and steroid are given as premedications 30 to 60 minutes before the infusion of Ocrevus begins.

  • How long does an Ocrevus infusion take?

    Typically, infusions last between two and two-and-a-half hours. If you experience any infusion reactions, your healthcare provider may slow the rate of your infusion to prevent further reactions. This will lengthen the overall time of the infusion, but it is a necessary precaution to minimize unwanted adverse reactions sometimes associated with Ocrevus infusion. You will be monitored for one hour after the infusion is complete. Plan for a typical infusion visit to last four to six hours from start to finish.

  • What if I show signs of an infection while on Ocrevus?

    If you believe that you may have an infection, it is very important to let your healthcare team know before your next infusion. Your infusion may need to be postponed or delayed while the infection is addressed and treated. As Ocrevus works by interfering with certain parts of your immune system, you may be more prone to infections while on Ocrevus, and these infections may require treatment. Do not delay in alerting your healthcare provider to any potential infections you may have.

How Can I Stay Healthy While Taking Ocrevus?

Ocrevus can significantly delay the progression of MS and improve quality of life, but there are additional steps you can take to gain the most benefit from this treatment. 

Before your first infusion, be sure to discuss the following with your healthcare provider:

  • Vaccine history: It is much more challenging to receive vaccines after beginning Ocrevus, so it's important to address any vaccination needs before your treatment.
  • Any current or previous chronic infections, such as herpes or hepatitis
  • Cancer history
  • Family medical history

Attend all of your scheduled infusion visits and report all potential infections and any infusion reactions that you may be experiencing.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

The author would like to recognize and thank Jonathan Toellner for contributing to this article.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. National Multiple Sclerosis Society. Ocrevus.

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  4. Kelsey A, Casinelli G, Tandon M, Sriwastava S. Breast carcinoma after ocrelizumab therapy in multiple sclerosis patients: a case series and literature review. J Cent Nerv Syst Dis. 2021;13:117957352110377. doi:10.1177/11795735211037785

  5. Mulero P, Midaglia L, Montalban X. Ocrelizumab: a new milestone in multiple sclerosis therapy. Ther Adv Neurol Disord. 2018;11:1756286418773025. 2018. doi:10.1177/1756286418773025.