• There are about 20 different disease-modifying therapies (DMTs) currently available to treat relapsing forms of multiple sclerosis (MS).
• Some DMTs may be taken orally, while others are injected or infused intravenously (through a vein).
• Your doctor may recommend a DMT based on factors including your disease activity, your risk for developing serious side effects, and which treatments you have tried before.
• The only way to know whether a DMT will be effective is to begin taking it.

As of January 2023, there were 18 different disease-modifying therapies approved by the U.S. Food and Drug Administration (FDA) for treating relapsing MS. Each DMT has been proven in multiple clinical trials to reduce the frequency of clinical attacks (also called relapses, flare-ups, or exacerbations) and the development of new brain lesions and spinal cord damage. Some DMTs have also been proven to slow the accumulation of disability.

Overall, DMTs slow disease progression and might help keep relapsing MS stable. Relapsing forms of MS include clinically isolated syndrome, relapsing-remitting multiple sclerosis (RRMS), and active secondary progressive MS.

With so many treatment options, how can someone diagnosed with relapsing MS know which MS treatment will be best for them? For some people, how a DMT is taken and how often it is taken are important factors, especially considering DMTs are taken long term, usually for years. Some prefer a medication taken orally over one taken by injection or intravenous infusion. Others prefer a more convenient dosage schedule with medication taken only a few times a year. It can also help to know how different classes of DMTs work.

Read on to find out which DMTs are prescribed for relapsing forms of MS, how each is taken, and what may lead doctors to recommend one over another.

Weighing the Risks and Benefits of DMTs

All medications, even those sold over the counter, have potential side effects. Treatments for relapsing MS are no different, and each has possible risks.

Risks Vary Between Individuals

Some side effects are more common, and others are extremely rare. Risk-averse people may prefer to avoid DMTs with a potential for serious side effects, even if those side effects occur very rarely. Others may prefer to focus on which DMT will be most effective in modifying the course of their MS, even if they carry a low risk for severe adverse effects. Your personal risk for developing serious side effects depends on many factors. Your doctor can help you understand your risk for side effects with any medication.

Some DMTs have contraindications — circumstances that raise the risk for serious side effects in people with other health conditions in addition to MS. For instance, some DMTs are not recommended for people who test positive for the human polyomavirus 2 — also known as JC virus or John Cunningham virus — antibodies. Other DMTs may not be safe for people with liver dysfunction. If you have any other health problems or conditions, your doctor may avoid prescribing certain DMTs.

Active MS May Call for Different Treatment

Doctors may recommend DMTs based on many factors. One important factor is MS disease activity. An individual’s MS may be active or inactive. Active disease is defined as having a clinical relapse or detecting new lesions on an MRI scan over a period of time, usually a year. When your MS is active, you’re more likely to experience new damage to the central nervous system. Doctors may recommend different DMTs based on whether your MS is considered to be active or inactive.

List of Treatments for Relapsing MS

According to the Consortium of Multiple Sclerosis Centers (CMSC), a large membership organization of health care providers for those with MS, any approved DMT may be considered as an initial treatment for someone diagnosed with a relapsing type of MS based on what is best for that individual.

The following DMTs have been approved by the FDA to treat relapsing forms of MS.

Changing DMTs

Remember that no DMT can cure or completely stop MS. According to the CMSC, switching treatments may be considered when:

• Your MS is not responding adequately to treatment. This is a subjective measurement, but signs may include a relapse, new or worsening lesions, or worsening results during a neurologic exam within a year of starting therapy.
• You have significant side effects on the first therapy, or a new health concern or contraindication raises the risk for side effects.
• You no longer have access to the first DMT.
• You have trouble taking the first DMT or cannot tolerate its side effects.

You’ll need to communicate with your health care provider when you believe you’re having a relapse. It can sometimes be difficult to know whether you’re experiencing a clinical MS relapse or MS symptoms made worse by stress or infection. Read more about how to know when you’re having a relapse, what they feel like, and how long they last.

How Does Each Class of Medications for RRMS Work?

Among the DMTs approved for treating RRMS, there are several mechanisms of action — in other words, different ways of working. Most DMTs modify different aspects of the immune system to prevent autoimmune attacks on the myelin that sheathes nerve fibers. Understanding how DMTs work can provide insight into why your doctor recommends a medication. For instance, if you are switching drugs because the DMT you have been taking has been ineffective, your doctor will likely recommend a drug with a different mechanism of action.

Here’s a breakdown of DMTs for relapsing MS by mechanism of action.

For people living with active relapsing MS, the only way to know whether a DMT will be effective is to begin taking it. Many people with relapsing MS find it necessary to switch to a different DMT over the course of their treatment.

For better conversations with your neurologist about treatment options for relapsing MS, read What To Tell Your Physician About Relapsing MS Treatments and 13 Things To Ask.

Talk With Others Who Understand

On MyMSTeam, the social network for people with multiple sclerosis and their loved ones, more than 195,000 members come together to ask questions, give advice, and share their stories with those who understand life with MS.

Do you still have questions about disease-modifying treatments for relapsing MS? Share them in the comments below or start a conversation with others on MyMSTeam.