Is My MS Treatment Working?

Medically Reviewed by Jennifer Robinson, MD on May 01, 2023
3 min read

Multiple sclerosis (MS) is a complex disease that often requires a mix of treatments. Some improve symptoms and quality of life. Only one, however, can slow the disease. That treatment is known as a disease-modifying drug.

You don’t need a doctor to tell you whether drugs for your symptoms are working. If you’re taking medicine designed to fight fatigue, you should feel more energy. If you take a laxative, you should get some relief from the constipation associated with MS.

You may need a doctor, however, to find out if your main MS treatment -- your disease-modifying drug -- is working. That’s mostly because new disease activity might show up on a brain scan even if your symptoms don’t seem to be any worse.

If you have relapsing-remitting MS, your doctor will suggest you start taking a disease-modifying drug as soon as you’re diagnosed. These medications work with your immune system to reduce inflammation in the brain and spinal cord. The goal is to slow the formation of new brain lesions and reduce the rate of MS flare-ups, called relapses.

What a disease modifying drug won’t do: Treat your symptoms, cure your MS, or make you feel better. In fact, you may not feel your medicine is doing anything besides causing side effects. Common ones include:

  • Pain and swelling where the needle went in your skin
  • Flu-like symptoms
  • Liver problems

When you’re sick, you want your medicine to work fast. Only some MS treatments do, and these are the ones that target symptoms.

Some pain relieving medications, for example, can work pretty fast. So can drugs that shorten a relapse. For instance, if you have a severe flare-up, your doctor may give you a 3-to-5-day course of IV corticosteroids. But these powerful anti-inflammatory drugs don’t work on the disease itself.

Drugs that slow down disease progression take much longer to work. It may be months before your disease-modifying drug reins in the nerve-damaging course of MS. During this time you may even have a relapse, but that doesn’t mean the drug isn’t working. Because there’s no drug that can cure MS, relapses will eventually happen.

Regular checkups with your neurologist are par for the course with MS. In general, you should expect to visit your doctor every three months and get a magnetic resonance imaging (MRI) brain scan every 12 months to find out if your disease-modifying drug is working. Some things your doctor will consider:

  • How many relapses you’ve had
  • How severe the relapses were 
  • The number of lesions they see on your MRI
  • Changes in your physical abilities that have lasted for a few months

Switching to a new drug is common when your existing one isn’t working well enough. If you’ve been on one disease modifying therapy for a while, you may need to switch if you continue to have relapses, you have new MRI-detected lesions, or your disability increases.

MRI is the best tool doctors have to both diagnose and monitor MS. It can detect even small changes in your brain, spinal cord, or other body parts. MS lesions show up on MRI scans as either white spots or darkened areas.

MRIs can reveal more than just the presence (or absence) of growing lesions. By looking at the impact of treatment on MRI lesions, they may be able to predict relapses and future treatment failure.

There are no hard and fast rules about how often to get an MRI. While most guidelines say once a year, that can vary depending on your other health issues and how long you’ve had the disease. If you’ve been recently diagnosed, you may get an MRI 3 to 6 months after you start taking a disease-modifying drug.

When your doctor suggests an MRI, it’s wise to follow through and get scanned. It’s the best way to know for sure if your MS treatment is working.