Side effects of MS

Side Effects of Multiple Sclerosis Medications

More than a dozen disease-modifying medications are FDA-approved to treat relapsing forms of multiple sclerosis (MS). Specifically, these drugs help prevent relapses and slow progression of the disease.

Disease-modifying medications are also called “immunomodulators,” because they affect the functioning of your immune system.

“All these therapies highlight the increased choices and options for patients living with MS and the ability of physicians to select a therapy based on individual characteristics,” says Ari Green, MD, assistant clinical director of the UCSF Multiple Sclerosis Center and director of the UCSF Neurodiagnostics Center in San Francisco.

But all drugs can have adverse side effects, and those associated with MS medications range from mild (such as flu-like symptoms or irritation at an injection site) to serious (such as progressive multifocal leukoencephalopathy , a viral disease in the brain).

One of the challenges of treating multiple sclerosis is balancing risk and benefit, says Dr. Green. Stronger medications might be more effective at slowing progression of the disease, but they may also be associated with more risks.

Discussing MS Medication Side Effects With Your Doctor

“A doctor has to have a frank and open discussion to find out what is tolerable for patients,” says Green. “Some side effects go away as the body gets used to MS medications, but others, such as irritation where the injection takes place, do not.”

Because people experience side effects differently, each individual has to decide which side effects he or she can live with, he adds.

In some cases, what are thought to be drug side effects may actually be MS symptoms. Fatigue and headache, for example, may be either.

Keeping a detailed log of your symptoms can help your doctor determine whether you are experiencing a symptom of multiple sclerosis or a medication side effect.

Make a note of when your symptom began, how long it lasted, what might have triggered it, and whether anything you did eased the symptom.

“The more patients are engaged in keeping track of things, the more they can be positively and appropriately engaged in directing their own care,” says Green. This information can also help your provider select appropriate therapies in the future.

Managing MS Medication Side Effects

Some simple steps can often help you manage the most common side effects of MS medications:

Infection risk Some of the immunomodulatory medications increase your risk of common infections, so it’s important to practice prevention strategies such as washing your hands frequently and limiting your contact with people who are ill.

Flu-like symptoms Fever, chills, achiness, and feeling generally under the weather are not uncommon following interferon beta injections, leading some users to stop the medication. Interferon beta medications include Betaseron, Extavia, Avonex, Rebif, and Plegridy.

According to nurses with expertise in MS care, the following steps can help to manage these side effects:

  • Staying hydrated
  • Eating healthfully
  • Taking medications before sleep
  • Warming injectable medicines up to body temperature before injecting

You can also take a small dose of Advil, Motrin, or Nuprin (ibuprofen) an hour before and an hour after your injection. Tylenol (acetaminophen), Aleve (naproxen), or Benadryl (diphenhydramine) may also help ease these side effects, Green says.

RELATED: 6 Side Effects of MS Steroid Treatment

Injection-site irritation Applying ice to your injection sites before injections, and a warm compress afterward, can help ease any irritation.

Some people may also benefit from some retraining on the finer points of giving themselves injections, notes Green. This is especially true because most people learn how to give self-injections right after their diagnosis — a period when they’re absorbing lots of information about the disease.

If you’re having trouble injecting your MS medication, speak to your healthcare provider about working with an MS nurse for training in self-injections.

Heart health The medication Gilenya (fingolimod) is known to slow some users’ heart rate within the first six hours after the first dose. Because of this, your doctor may advise you to have your first dose in a clinical setting, where your pulse and blood pressure can be monitored.

Distinguishing Drug Side Effects From MS Symptoms

The immediate side effects of MS medications may be more apparent once you experience them. Immediate side effects, such as flu-like symptoms and chills, are easy to discern, says Green. Even the muscle aches and pains that can occur immediately after taking disease-modifying MS medications differ from the pain associated with multiple sclerosis.

The one rare medication side effect that might be hard to distinguish from an MS symptom is PML, which has been related to use of the drug Tysabri (natalizumab). PML, however, will progress much more quickly than multiple sclerosis — a good reason to stay on top of your medical checkups.

Ongoing Medication Monitoring

Most of the medications prescribed for MS require regular blood tests to keep track of the treatment’s effect on your body, including your liver.

The drug Lemtrada (alemtuzumab) requires blood and urine monitoring before, during, and for four years after treatment is given to watch for serious autoimmune conditions associated with the drug.

In addition to monitoring for side effects, you and your doctor should monitor for positive effects of drugs as well. Green says that a change in therapy is needed if you are having more than one MS relapse a year, if multiple new brain lesions are seen on your MRI, or if your symptoms are progressing despite treatment. Switching medications is a decision you and your doctor should make together.


Multiple sclerosis

Read more about treating urinary incontinence.

Bowel problems

It may be possible to treat mild to moderate constipation by changing your diet or taking laxatives.

More severe constipation may need to be treated with suppositories, which are inserted into your bottom, or an enema.

An enema involves having a liquid medicine rinsed through your bottom and large bowel, which softens and flushes out your stools.

Bowel incontinence can sometimes be treated with anti-diarrhoea medicine or by doing pelvic floor exercises to strengthen your rectal muscles.

Speech and swallowing difficulties

A speech and language therapist can help you find ways to overcome problems with speech and swallowing.

For example, they can offer advice about foods that are easy to swallow and recommend exercises to strengthen the muscles used in speech and swallowing.

If swallowing problems become very severe, some people need to be fed using a tube, which is fitted into the stomach through the skin.

Further information

  • MS Society: signs and symptoms
  • MS Trust: treating MS symptoms

Fingolimod (Gilenya)

  • :What it treats: Relapsing MS
  • How you take it: A pill by mouth
  • How often: Daily
  • Common side effects: Headache, diarrhea, back pain, and abnormal liver tests
  • Support Program: ABOVE MS 800-456-2255

Glatiramer acetate (Copaxone)

  • What it treats: Relapsing-remitting MS
  • How you take it: Injection under the skin
  • How often: Three times per week
  • Common side effects: Skin reaction where the needle went in, weakness
  • Support program : 800-887-8100

Interferon beta-1a (Avonex)

  • What it treats: Relapsing forms of MS. Also given after an initial episode of inflammation.
  • How you take it: Injection into a muscle
  • How often: Weekly
  • Common side effects: Mild flu-like symptoms, reaction where the needle went in
  • Support program : 800-456-2255

Interferon beta-1a (Rebif)

  • What it treats: Relapsing forms of MS
  • How you take it: Injection under the skin
  • How often: Three times per week
  • Common side effects: Mild flu-like symptoms, reaction where the needle went in
  • Support program : 877-447-3243

Interferon beta-1b (Betaseron)

  • What it treats: Relapsing forms of MS
  • How you take it: Injection under the skin
  • How often: Every other day
  • Common side effects: Mild flu-like symptoms
  • Support program : 800-788-1467

Mitoxantrone (Novantrone)

  • What it treats: Rarely used for rapidly worsening relapsing-remitting MS and for progressive-relapsing or secondary-progressive forms of MS
  • How you take it: Through an IV infusion
  • How often: Every 3 months or four times a year for a total of 8-12 doses
  • Common side effects: Nausea, hair thinning, decreased white blood cell count
  • Support program : 877-447-3243

Peginterferon beta-1a (Plegridy)

  • What it treats: Relapsing forms of MS
  • How you take it: By autoinjector or prefilled syringe
  • How often: Three times per week
  • Common side effects: Reaction where the needle went in, flu-like symptoms
  • Support program : 800-456-2255


  • What it treats: Relapsing forms of MS
  • How you take it: Through an IV infusion
  • How often: Every 4 weeks
  • Common side effects: Headache, feeling tired, and joint pain
  • Support program : 800-456-2255


  • What it treats: Relapsing or primary progressive forms of MS
  • How you take it: Through an IV infusion
  • How often: Every 6 months
  • Common side effects: Rash, headache, fever, nausea, infections
  • Support program: 844-OCREVUS

Which Are the Safest (and Least Safe) MS Drugs on the Market?

The results are in, and according to a recent report comparing the safety records of all multiple sclerosis (MS) drugs on the market, Tecfidera took the top safety prize. The report reveals that newer MS drugs received high marks for safety, while older interferon drugs had more reported side effects.

California-based health informatics company AdverseEvents analyzed side effects data from the U.S. Food and Drug Administration’s (FDA) Adverse Event Reporting System (FAERS) database. The FDA asks that doctors, consumers, and drugmakers report any serious negative health events they or their patients experience while taking an FDA-approved drug.

Take a Look at MS by the Numbers “

Using a formula called the “reporting odds ratio” (ROR), analysts compare how often an adverse event (AE) has been reported, regardless of drug, to how often the event has been reported for a specific drug in the FAERS database. This helps safety professionals identify AE and drug pairs with a higher than usual occurrence of a particular side effect, sending up a red flag.

Because the ROR is a ratio that is not affected by length of time a drug has been on the market, the analysts at AdverseEvents were able to compare the oldest MS drugs with the newest and compile accurate results, giving each drug an “RxScore.”

So, comparing the AEs reported for all MS drugs only during the time period since Tecfidera won approval did not affect the outcome, said Keith Hoffman, Vice President of Scientific Affairs at AdverseEvents, in an interview with Healthline. “We have completed that time comparison with other drug classes many times and the overall results stayed the same.”

A Few Bad Apples

The RxScore scale ranges from 0 to 100, with higher numbers indicating a greater risk of adverse events. Avonex, Rebif and Betaseron, all interferons, had the worst safety records, with scores between 53 and 55. Copaxone had the fourth highest score at 47.4.

Betaseron had the highest ratio for reports of disability or death, while Avonex users were hospitalized due to AEs the most often.

People taking Avonex reported more malignant tumors, breast cancer diagnoses, and flu-like symptoms than those taking other drugs, while Betaseron users reported more heart attacks, bacterial infections, and liver problems.

Rebif received the worst RxScore, with a higher proportion of negative events including suicidal behavior, optic nerve inflammation, and cancers of the female reproductive system.

Copaxone fared worst for life-threatening allergic reactions and psychiatric symptoms. But Copaxone, FDA-approved in 1996, scored best on measures of several side effects, including cognitive disorders and flu-like symptoms, making it the safest of the older first-line MS drugs.

What are MS Drug Therapy Choices? “

The Best of the Bunch

Tecfidera attained the lowest RxScore of 33 and the lowest ROR of life-threatening events, hospitalizations, disability, or death. It also scored lowest for everything from bacterial infections to optic nerve disorders and liver problems. Overall, Tecfidera had the lowest ROR for 24 out of the 58 side effects the researchers studied.

Gilenya scored second best at 39.4, but users had more cardiac-related AEs, including lowered heart rate, and the drug also scored the worst for vision disorders and skin cancers. Gilenya, FDA-approved in 2010, did not hold the lowest score for any reported AEs.

Aubagio, with the same RxScore as Gilenya, had the highest number of reports of diarrhea, but that’s the only side effect for which it scored the highest, making it among the safest of the MS therapies.

Tysabri scored relatively well but had the highest ROR for cognitive disorders, JC virus positive tests, and secondary progressive MS. The report also concluded that the relationship between Tysabri and primary multifocaleukoencephalothopy, or PML, a rare and deadly brain infection, was confirmed.

Extavia had the worst safety score of any of the new MS drugs at 44.9, and users suffered the most depression, falls, headaches, and injection site reactions.

Understand the JC Virus and the Risks for MS Patients “

What Does It All Mean?

The FAERS database only examines side effects, not effectiveness. And it cannot predict side effects that may emerge over time.

“We are limited by what is recorded into FAERS,” Hoffman points out. “If a safety concern takes years to manifest after a drug’s approval we will not see those reports until they are filed.”

Although this report is an effective tool for neurologists recommending drugs to their patients, doctors must also consider each drug’s effectiveness. Does it have a track record for reducing relapses, preventing disability, or protecting neurons?

Weighing the risks and benefits is a crucial process when selecting a drug for an MS patient. And everyone’s MS experience is different. Nobody will have all of the reported side effects—or all of the benefits.

Discover Alternative Ways to Conquer Your Symptoms “

The main benefits of taking one of the DMDs are:

  • Fewer relapses
  • Less severe relapses
  • Reduce the build-up of disability which can occur if you don’t recover completely from relapses

DMDs work with different parts of the immune system to reduce the inflammation caused by MS to nerve cells in the brain and spinal cord. This helps reduce the number and severity of relapses.

Inflammation does not always result in a relapse or visible symptoms. This silent activity may mean that although you are feeling well, there may still be changes caused by your MS that can only be seen on a brain scan. MRI scans show that taking a DMD can lead to fewer, smaller or no new areas of damage (lesions) in the brain and spinal cord. Treating the visibly active (relapses) as well as the silently active aspects of MS is a new goal that is emerging in MS treatment. This goal is often called no evidence of disease activity (NEDA). The aim is to reach a point where you are free of visible (relapses) and invisible (changes seen only on brain scans) MS disease activity.

On average, people with relapsing remitting MS have one or two relapses a year. In the NHS, DMDs are approved for prescription according to how frequently you have been having relapses. The NHS describes relapsing remitting MS as being either active or very active:

Active relapsing remitting MS

Your MS may be described as active if you’ve had two relapses in the previous two years.

Very active relapsing remitting MS

Your MS may be described as very active if it has been either:

  • highly active despite treatment – if you continue to have relapses even though you’ve been taking a DMD for a year


  • rapidly evolving severe – if you have had two or more severe, or disabling relapses in the previous year and show areas of new damage (lesions) on two consecutive MRI scans.

Some research suggests that DMDs work best when they are started as soon as possible after diagnosis, effectively before there is any sign of disability, to reduce the build-up of damage to nerve cells.

It may take three to six months from starting treatment for a DMD to become fully effective, so the benefits of treatment may not be immediately obvious.

Most people will continue to have a background of symptoms. DMDs are not able to repair nerve damage already caused by MS so they cannot reverse existing symptoms.

When used to treat clinically isolated syndrome, some of the DMDs have been shown to delay further episodes that would lead to a definite diagnosis of MS.

None of the DMDs is recommended for people with secondary progressive MS who no longer experience relapses or for people with primary progressive MS. Some people with secondary progressive MS who continue to have disabling relapses may benefit from taking one of the DMDs.

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