Understanding MS Drugs

A treatment plan for multiple sclerosis (MS) can involve different types of drugs. The main category is known as disease-modifying therapies (DMTs). These are used to reduce MS activity and slow down the progression of the disease. Some other drugs can combat MS flares and symptoms so that those living with MS can feel and function at their best.

This article will provide a brief overview of how disease-modifying therapies treat MS, as well as insight into the other various MS drugs used to treat flare-ups and daily symptoms.

Person taking drugs for multiple sclerosis


How Do MS Drugs Work?

DMTs are "big-picture" drugs intended to improve the long-term outlook of a person's disease. They work to decrease MS relapses (flares of symptoms), limit the number of lesions (areas of inflammation) on imaging tests, and slow the overall course of the disease.

There are more than 20 DMTs approved by the Food and Drug Administration (FDA). They vary in their mode of action, level of effectiveness, side effects, and delivery method (injection, oral, or IV infusion).

Injectable DMTs can be administered at home as a shot into one of your muscles (intramuscular) or beneath your skin (subcutaneous). Infused DMTs are given through a needle placed in your vein at a healthcare facility.

Summary of MS Drugs
 Injectables  Oral Infused
Avonex, Rebif (interferon beta-1a) Gilenya (fingolimod) Tysabri (natalizumab)
Betaseron, Extavia (interferon beta-1b) Mayzent (siponimod) Ocrevus (ocrelizumab)
Plegridy (peginterferon Zeposia (Ozanimod) Lemtrada (alemtuzumab)
Copaxone and Glatopa (glatiramer acetate) Tecfidera (dimethyl fumarate) Novantrone (mitoxantrone)
Kesimpta (ofatumumab) Vumerity (diroximel fumarate)
Bafiertam (monomethyl fumarate)
Aubagio (teriflunomide)
Mavenclad (cladribine)

While all DMTs work to some effect to reduce immune system attacks within the brain and spinal cord, some are more targeted than others.

For example, the monoclonal antibodies Ocrevus (ocrelizumab), Kesimpta (ofatumumab), and Lemtrada (alemtuzumab) recognize and bind to selective docking sites on B cells or T cells.

What Are B Cells and T Cells?

B cells and T cells are white blood cells involved in immune system attacks on myelin in MS.

Specifically, Ocrevus and Kesimpta work by destroying and removing B cells with a CD20 docking site. Lemtrada works by eliminating T cells or B cells with a specific CD52 docking site.

Another monoclonal antibody, Tysabri (natalizumab), also targets T cells. It sticks to a specific molecule on T cells (called α4-integrin). By binding to this molecule, T cells are hindered from traveling into the brain and spinal cord and damaging myelin.

Other, typically older, DMTs have a less clear or specific mode of action.

For instance, the oral drug Tecfidera (dimethyl fumarate) is believed to protect nerve cells from damage through anti-inflammatory and antioxidant properties.

Likewise, the beta-interferon drugs (e.g., Avonex or Betaseron) are manufactured versions of proteins that work to quiet down the inflammation that damages nerves in MS.

Bottom Line

All MS DMTs work to prevent disease activity by reducing inflammation. That said, their specific mode of action varies, with some drugs being more targeted (and perhaps more effective) than others.

How Long Do MS Drugs Take to Work?

A 2020 study in Brain investigated the time it took for 10 different DMTs to reach their maximal effect in people with multiple sclerosis.

Results revealed that it took between three to seven months to reduce relapses and seven to 17 months for a delay in disease progression.

Bottom Line

It can take months, if not over a year, for your MS DMTs to reach its full potential. Factors like preexisting disability and drug adherence (taking medications exactly as prescribed) may also affect this timeline.

How Do You Know If It’s the Right Drug for You?

There are no set-in-stone guidelines for selecting an MS DMT.

Rather, you and your neurologist (a doctor specializing in diseases of the nervous system) will consider several factors like how aggressive your disease is and the drug's safety profile and delivery method. Cost, accessibility, and lifestyle factors like plans for pregnancy are also important considerations.

Once you have selected and started a DMT, your neurologist will see you every three to six months.

During these follow-up appointments, your neurologist will monitor you for side effects and any signs of disease activity by inquiring about symptoms and performing a neurological examination.

They may also ask you questions using the Expanded Disability Status Scale (EDSS) tool to help track disease progression.

To check for silent lesions, which are areas of inflammation in the absence of symptoms, you will undergo periodic magnetic resonance imaging (MRI) scans of your brain and/or spinal cord.

If you experience a new severe relapse or multiple relapses, or if your MRI reveals new lesions, you may need to switch your DMT.

Bottom Line

MS is an individualized disease. People respond uniquely to different drugs, so what works for one person may not work safely or well for you.

Drugs for Relapses

DMTs are intended to decrease the number and severity of MS relapses, but they do not treat individual relapses.

Treatment for an MS relapse is typically advised when symptoms negatively impact a person's ability to function, such as trouble walking or losing your vision, or are particularly unpleasant, like numbness.

In such cases, a three-to-five-day course of corticosteroids (also called steroids), either Solumedrol (methylprednisolone) or prednisone, is usually prescribed. Solumedrol is administered as an IV infusion in a healthcare facility. Prednisone is taken by mouth at home.

Less commonly, neurologists prescribe intravenous immune globulin (IVIG) or adrenocorticotropic hormone (ACTH) gel injections to treat MS relapses.

Drugs for Daily Symptoms

DMTs do not treat daily MS symptoms like painfatigue, numbness, or spasticity (muscle tightness or stiffness preventing natural movement). Instead, separate medications (along with lifestyle behaviors and rehabilitation therapies) are used to manage the everyday symptoms of MS.

For example, if you are experiencing pain associated with spasticity, your neurologist may prescribe a muscle relaxant like Kemstro (baclofen) or Zanaflex (tizanidine).  

For MS-related fatigue, your neurologist may prescribe a drug to promote wakefulness called Provigil (modafinil) or a stimulant called Ritalin (methylphenidate).

Non-Medication Treatments

Healthy lifestyle behaviors, like getting enough sleep and eating a well-balanced diet, can ease certain MS symptoms like fatigue and depression.


Numerous drugs are used to treat MS, including disease-modifying therapies (DMTs) and medications for relapses and specific symptoms. The primary goal of all DMTs is to prevent MS activity by reducing inflammation in the brain and spinal cord. DMTs do not treat MS relapses or symptoms

A Word From Verywell

Creating an MS treatment plan takes time and effort. Do your best to gain as much knowledge as you can about the various drug options available. Also, under the guidance of your neurologist, be sure to carefully review the side effect profiles of each drug and what you can realistically expect in terms of the drug's benefit.

Frequently Asked Questions

  • What treatment is best for multiple sclerosis?

    There is no single best treatment for multiple sclerosis. You and your neurologist will devise your treatment plan based on your MS type, severity, and symptoms. The treatments' safety profile must also be considered.

  • Can you live with MS without medication?

    The course of MS varies from person to person, so there is no way to predict exactly how someone's disease will play out.

    Nevertheless, DMTs decrease MS relapses and activity and delay disease progression. Therefore, while you can technically live with MS without medication, you may experience more frequent relapses and a higher level of disability over time.

  • How effective are MS drugs?

    MS drugs known as disease-modifying therapies (DMTs) vary in their level of effectiveness. Research suggests that the monoclonal antibody drugs Tysabri (natalizumab), Ocrevus (ocrelizumab), Lemtrada (alemtuzumab), and Kesimpta (ofatumumab) are highly effective drugs; however, they have more serious safety concerns, including infections.

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