5 Reasons You Might Switch Your MS Medication

Even though multiple sclerosis (MS) cannot be cured, medications called disease-modifying therapies (DMTs) can reduce the number and severity of relapses, or periods of new or worsening symptoms. DMTs can also slow the progression of the disease and delay disability.

There are nine classes of DMTs available, all varying in their level of effectiveness, mode of action, side effects, delivery method, and dosing schedule. Switching from one DMT to another is a common event, but needs to be done carefully and thoughtfully to prevent any worsening of MS activity.

This article will explore the various reasons why people may need to switch their DMT, ranging from lifestyle to disease or drug-related factors. People with MS, their family, and caregivers should learn these reasons so they can communicate with their healthcare provider and make treatment decisions together.

Person with MS discussing switching DMT medication with healthcare provider

Natalia Gdovskaia / Getty Images

Reasons to Switch MS Medications

Lack of Benefit

Research suggests that lack of benefit is the most common reason for stopping a DMT and switching to another one.

Signs that a DMT may be ineffective for you include:

DMTs reduce but do not eliminate MS relapses and MRI activity. You may still need treatment for symptoms in addition to a DMT. Discuss this with your healthcare provider so you better understand what to expect.

Unpleasant or Serious Side Effects

DMTs have unique side effects that may become too unpleasant or even dangerous.

A classic example of possible unpleasant side effects are those associated with the interferon beta drugs (e.g., Betaseron or Avonex). These injectable drugs can cause flu-like symptoms (fever, chills, and muscle aches) and injection site reactions (redness, tenderness, or swelling of the skin).

Some people may be able to combat side effects with simple strategies like taking an over-the-counter (OTC) pain reliever or applying a cold compress to the skin.

Others may find the side effects too uncomfortable or bothersome to continue with the drug. In such cases, switching medications may be warranted. Talk with the healthcare provider responsible for your MS care.

Switching DMTs is also warranted if the possible side effects are too serious for an individual and outweigh the benefits of the drug.

As an example, the infused drug Tysabri (natalizumab) increases your risk of developing progressive multifocal leukoencephalopathy (PML). PML is a rare, dangerous brain infection caused by the reactivation of the John Cunningham (JC) virus.

The risk is estimated at four per 1,000 people treated with the drug who have antibodies to the virus. The risk is higher with longer use of the drug and being immunosuppressed. Some other drugs that treat MS have an even smaller risk of PML.

Discontinuation of Tysabri may be warranted if a patient becomes infected with the JC virus. Infection is determined by a blood test that looks for antibodies against the JC virus.

Frustrations With Delivery Method

One of the benefits of MS DMTs is that they come in three different forms:

  • Injectable DMTs are given as a shot into one of your muscles (intramuscular) or beneath your skin (subcutaneous).
  • Oral (by mouth) therapies are taken at home.
  • Infused DMTs are given through a needle placed in your vein at a healthcare facility.

People may not like a particular delivery method (e.g., fear of needles) or find it inconvenient (e.g, driving to an infusion center). In these cases, they might consider switching to another DMT after speaking to their healthcare provider.


Switching DMTs out of financial concern is also an unfortunate, but all too real, scenario.

A survey released by the National MS Society revealed the economic burden of taking a DMT on patients living with MS.

Results from the surveyed participants included:

  • 40% reported that they delayed, skipped, or stopped taking their DMT due to high cost.
  • More than 50% expressed concern about being able to afford their medication over the next few years.
  • 40% experienced stress related to high out-of-pocket costs.
  • Almost 40% reported making sacrifices to pay for their DMT (e.g., not saving for their future).

If you (or a loved one) are experiencing stress and anxiety from escalating DMT prices, high out-of-pocket costs, or changes in insurance coverage, please reach out to your MS care team.

Your healthcare provider may be able to expedite coverage by writing a letter or making a phone call to your insurance company. In addition, pharmacy manufacturers sometimes offer programs that can cover all or part of your DMT cost.

Fertility and Pregnancy

People living with MS may need to switch their DMT if they are considering pregnancy.

Some MS DMTs are known teratogens (substances that may lead to birth defects) like Aubagio (teriflunomide) and Novantrone (mitoxantrone). Others are possible teratogens, such as Gilyena (fingolimod), Mayzent (siponimod), and Mavenclad (cladribine).

For other DMTs, their safety for use in pregnancy remains unclear. In these cases, the possible risk of causing fetal harm by taking a DMT must be weighed against the increased risk of MS relapse and progression from stopping the DMT.

While there is no formal approach for guiding MS DMT use in pregnancy, your healthcare provider may recommend that you stop your DMT and plan for pregnancy when your disease has been stable for at least a year.

Depending on the DMT you are taking, a washout period (a time frame so the drug can be fully eliminated from the body) is also usually recommended.

Teratogenic MS DMTs

Teratogens are substances that can cause harm to a developing embryo or fetus. All MS DMTs that are known or possible teratogens are contraindicated in people who are pregnant or people of childbearing potential who are not using effective contraception.

This includes either parent, as some of these medications are also detected in human semen. People of all sexes who may contribute an egg or sperm to the conception or bear a pregnancy should talk to their healthcare provider about the most effective methods for contraception.

How Long Do MS Treatments Take to Work?

The time it takes to reap full benefits from a DMT is called therapeutic lag. While more investigation is needed, emerging research suggests that the therapeutic lag for reducing relapses is between three to seven months, depending on the specific DMT. It takes longer—around seven to 17 months—for a DMT to delay disease progression.

MS affects everyone differently. There is no way to precisely predict how fast someone's MS will progress.

List of MS Medications At a Glance

Below is a summary of approved disease-modifying therapies for treating MS:

Injectable DMTs

Injectable therapies include:

  • AvonexRebif (interferon beta-1a)
  • BetaseronExtavia (interferon beta-1b)
  • Copaxone and Glatopa (glatiramer acetate)
  • Kesimpta (ofatumumab)
  • Plegridy (peginterferon beta-1a)

Oral DMTs

DMTs that can be taken by mouth include:

  • Aubagio (teriflunomide)
  • Bafiertam (monomethyl fumarate)
  • Gilenya (fingolimod)
  • Mavenclad (cladribine)
  • Mayzent (siponimod)
  • Ponvory (ponesimod)
  • Tecfidera (dimethyl fumarate)
  • Vumerity (diroximel fumarate)
  • Zeposia (Ozanimod)

Infused DMTs

DMTs that are given by infusion include:

  • Lemtrada (alemtuzumab)
  • Novantrone (mitoxantrone)
  • Ocrevus (ocrelizumab)
  • Tysabri (natalizumab)

Stem Cell Transplant

DMTs are the mainstay of treatment for MS. However, a type of bone marrow transplant called autologous hematopoietic stem cell transplantation (aHSCT) may be an option for people whose disease continues to be very active despite the use of DMTs.

When to Get Another MRI

To rule out an MS relapse, you may need to undergo an MRI if you are experiencing new or recurring MS symptoms for more than one day.

Keep in mind that after being diagnosed with MS, your healthcare provider will perform periodic MRIs of your brain and/or spinal cord. Regular MRIs allow them to monitor for MS-related inflammation that occurs without symptoms. These areas of inflammation—called "silent" lesions—may indicate that you need to switch to a DMT of higher efficacy.

It’s OK to Feel Hesitant About Switching Meds

Switching from one DMT to another can be nerve-racking and stressful. Perhaps, you are worried about the new drug's side effects, cost, or effect on your MS health. Know that you are not alone in your decision.

Besides reaching out to your healthcare provider, consider seeking emotional guidance or comfort from an MS support group.

It might also be helpful to run your thoughts by an MS Navigator at the National MS Society. These are professionals who provide valuable resources that can help you get through the various emotional, financial, and logistical challenges associated with living with MS.


Taking a disease-modifying therapy (DMT) is essential to helping prevent MS flare-ups and slowing the disease. There are numerous DMTs available, all varying in their side effects, mode of action, and levels of effectiveness.

Switching from one DMT to another is common among people living with MS. Reasons include side effects, lack of benefit, and inconvenience. While there is no standard guideline or process for changing DMTs, minimizing the time between therapies is important for preventing worsening disease activity.

All MS agents have side effects, but it's important to understand them and speak with your healthcare provider about your concerns so that you can decide on the right treatment plan together.

A Word From Verywell

If you and your healthcare provider decide that switching DMTs is best for your MS condition and overall quality of life, try to focus your energy on moving forward with your new DMT as quickly as possible. This will help minimize the chances of any rebound MS activity.

Even if you are feeling well on your DMT (hopefully, this is the case), please continue to see your healthcare provider for your regular appointments and follow-up MRIs.

Frequently Asked Questions

  • How effective is Kesimpta vs. Ocrevus vs. Tysabri?

    Research suggests that Kesimpta is as effective as other monoclonal antibodies, including Ocrevus and Tysabri, in reducing MS relapses and disease progression.

  • Do neurologists switch your MS medications after a relapse?

    Not necessarily. When considering a DMT switch, your neurologist (specialist in conditions affecting the nervous system) will consider multiple factors like the severity of your relapse, your adherence to the DMT, and whether your MRI shows any new lesions. The safety profile of any potential new DMT is also taken into account.

  • What lifestyle changes help slow MS progression?

    Quitting smoking can help prevent your MS from progressing. Research also suggests that exercise and a nutritious, healthy diet may help slow the disease down.

  • Are there any medications to avoid with MS?

    It's possible that tumor necrosis factor (TNF) inhibitors like Enbrel (etanercept) may aggravate demyelinating diseases like MS. More research is needed to determine the link between MS and these anti-inflammatory drugs.

    Always tell your healthcare provider all the drugs you are taking, including prescription and OTC medications, vitamins, supplements, and herbal products.


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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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By Colleen Doherty, MD
 Colleen Doherty, MD, is a board-certified internist living with multiple sclerosis.