Disease modifying therapies (DMTs) are treatments for people with multiple sclerosis (MS) that can help change the course of their MS by reducing the number they may have and slowing down the buildup of disability in the long term.
DMTs are for people whose MS is considered active. This means you’re experiencing relapses or you have new or enlarging lesions on an MRI scan.
On this page, we look at what DMT medicines are, their benefits and risks and who to talk to if you’re thinking about starting a DMT.
We also have information about autologous haematopoietic stem cell transplantation (AHSCT).
Disease modifying therapies (DMTs) are treatments for people with multiple sclerosis. These treatments include medicines, which are sometimes referred to as disease modifying drugs (DMDs), and autologous haematopoietic stem cell transplantation (AHSCT), a type of stem cell transplant for MS.
DMTs work with different parts of the immune system to reduce new areas of inflammation and damage developing in the brain and spinal cord (central nervous system).
There are a range of DMTs available. These medicines vary in how effective they are at reducing relapses, how you take them and the possible side effects.
While DMTs cannot cure MS, they are important for managing MS. DMTs reduce the number of relapses and worsening of MS symptoms over time (progression).
Other treatments are used in MS to:
Are there DMTs for my type of MS?
Understanding of the way MS presents and progresses is constantly evolving. Traditionally, MS has been split into three types: relapsing remitting MS (RRMS), primary progressive MS (PPMS) and secondary progressive MS (SPMS).
Most DMTs licensed in the UK are for RRMS. There is currently one DMT licensed for PPMS and one DMT for SPMS. The DMTs for PPMS and SPMS are only suitable for some people with these types of MS.
Some people may have a first episode of neurological symptoms that lasts at least 24 hours and is not caused by anything such as a fever or infection. This is called clinically isolated syndrome (CIS) If you have been diagnosed with CIS which fulfils the McDonald criteria for RRMS, the same DMT options will be available for you.
What are the benefits of DMTs?
Research suggests that DMTs work best when they are started as soon as possible after diagnosis.
The main benefits of DMTs are:
- preventing or reducing relapses
- reducing the risk of developing secondary progressive MS
- slowing down the buildup of disability in the long term
- fewer, smaller or no new lesions
- maintaining or improving your quality of life.
We have more information about MS relapses.
DMTs take about 3 months to reach their full effect on the immune system, and so you may get relapses or new lesions in this period.
This does not mean that the DMT you have started is not effective.
DMTs do not repair nerve damage already caused by MS, so they cannot reverse existing symptoms. They aim to reduce and prevent further damage.
When used to treat clinically isolated syndrome, some of the DMTs have been shown to delay further episodes that would lead to a definite diagnosis of MS.
Before you start taking a DMT, your MS team will discuss the risks and benefits of the therapies with you. Together, you will decide if the benefits outweigh any potential risks and which DMT may be best for you.
This discussion will consider various factors.
All medicines, including DMTs, can potentially cause side effects.
Some people may not experience any side effects from taking a DMT. Some may find that any side effects ease after the first month or two as their body adapts to the medicine. For others, side effects may persist.
Your MS team will advise you on what kind of side effects to expect and how to manage them. If you are concerned about side effects you are experiencing when you start taking a DMT, speak to your MS team.
A few people find some of the side effects difficult to cope with and may need to switch to a different DMT. Some DMTs are associated with less common but potentially serious and life-changing side effects.
You will be routinely monitored while you are taking a DMT, usually through a specialist multiple sclerosis clinic. You can also speak to your MS team if you have any concerns.
Our individual DMT pages have information about the potential side effects of each therapy. They also have information about how and when you will be monitored, as this varies between therapies.
Some DMTs work by suppressing your immune system. Some, for example, reduce the ability of some white blood cells (lymphocytes) to move freely within the body. White blood cells help your body fight infections. When their ability to move freely is reduced, this can affect your body’s immune responses.
This may increase your risk of developing infections that could potentially become serious, although the risk is low.
Your MS team will monitor you on a regular basis when you are taking a DMT. If you are worried about infections, you can speak to them about this. They may also advise you on how to minimise the risk of infections.
If you’re considering taking a DMT, where appropriate, your MS team will proactively discuss family planning and the possibility of pregnancy with you.
If you are planning a pregnancy or wish to have a baby, you will usually be offered a DMT which is safe to take around the time of conception, or to continue during pregnancy. The DMT you’re offered will consider safety around pregnancy or family planning and also minimise your risk of relapses.
If you are having IVF (in vitro fertilisation) (NHS UK), you will usually be treated with a DMT that is safe to take during conception or pregnancy.
If possible, talk to your MS team as soon as you start thinking about having a baby. They will help you plan your treatment and work out which treatment is best for you.
If you are a man with MS who is considering trying for a baby, let your MS team know. They will advise on the best treatment options for you.
We have more information about pregnancy and MS.
People with MS are generally encouraged to have vaccinations which are part of the national vaccinations programme (NHS UK vaccinations). Where possible, your MS team will advise you to get relevant vaccinations before you start taking a DMT.
If you have MS and are taking a DMT that suppresses your immune system, you are generally advised not to take live vaccines. Some live vaccines, such as the yellow fever (NHS UK) vaccine, should be avoided while you are on a DMT.
We have more information about vaccination and immunisation.
When travelling to some places outside the UK, vaccinations may also be recommended. The NHS has travel vaccination advice (NHS UK). You can also find out more about which vaccinations are necessary or recommended for the areas you’ll be visiting on the Travel Health Pro website.
We also have information about holidays and MS, which covers aspects such as taking medications abroad.
DMTs and other conditions
If you have other conditions, such as high blood pressure that cannot be controlled by medicines, heart disease and some types of cancer, some DMTs may not be suitable for you. DMTs may also not be suitable for you if you are taking other medicines which suppress your immune system.
A few of the DMTs that suppress the immune system have been associated with skin cancers; however, the link is not clear.
Your MS team will help you decide what is suitable for you. They will also help you understand your individual risk and how to minimise it.
Who do I talk to about starting a DMT?
You will usually be assessed by a neurologist to check whether you meet certain criteria set out by the NHS and whether you are likely to benefit from taking a DMT. If you are not already under the care of a neurologist, your GP will refer you to one. This is because your GP cannot prescribe DMTs.
Your neurologist will likely work alongside a team which includes an MS specialist nurse and pharmacists. They will usually work with a multidisciplinary team (MDT) from a specialist MS centre to assess your eligibility for a DMT.
Your assessment will usually consider aspects such as:
- the number of relapses you have had in the last two years
- how active your MS is
- evidence of new or enlarging lesions on an MRI scan
- how relapses affect you
- your physical ability
- your medical history
- your individual circumstances and wishes.
If you are found to be eligible for a DMT, your MS team will work with you to find the right therapy for you.
Other aspects, such as your lifestyle, other conditions, and medications, will be considered when determining a suitable DMT for you.
You will not usually be required to pay for a DMT if you are eligible for NHS treatment, although you may need to pay prescription charges for some medicines.
Before starting treatment, your MS team will explain how the therapy works, how to take it, how to manage potential side effects and who to contact if there are any issues.
You will usually be closely monitored to check if the therapy is effective and safe for you. This may involve regular blood tests at your local hospital. You can also book the tests online at a community diagnostic centre (NHS England). You will also usually have an MRI scan 3 to 6 months after starting a DMT. This is because it can take up to 6 months for the benefits of the treatment to be seen.
You will then have an MRI scan every few years or if you have new symptoms or signs of progression. If you have questions or concerns about the DMT you’re taking, you can contact your MS team. You do not have to wait until you have an appointment.
Switching or stopping a DMT
In some cases, if you are finding a therapy intolerable or if it isn’t keeping your MS under control, you may need to be switched to a different one.
You will usually continue taking a DMT once you start; however, your MS team will regularly discuss your long-term treatment with you. New treatment options might also become available. They may consider stopping or switching your DMT if your MS is not as active or has moved to a progressive course, such as secondary progressive MS.
For example, there is some evidence to suggest that inflammation in MS decreases over time and as most people get older. In these cases, the benefits of DMTs may reduce, and you may be able to stop taking a DMT, or your MS team may recommend that you switch to a moderately effective DMT from a highly effective one. This is called de-escalation.
Some people who may be on a moderately effective therapy may be switched to a highly effective therapy in some cases. For example, after a relapse and an MRI scan that shows evidence of new lesions.
Your DMT may also be stopped or switched if you become pregnant or there are significant changes to your health.
It is important that you do not stop taking your DMT without speaking to your MS team, as any changes to your treatment need to be planned.
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Rashid W, et al.
Using disease-modifying treatments in multiple sclerosis: Association of British Neurologists (ABN) 2024 guidance
Practical Neurology 2024-004228
Full guidance (link is external)
National Institute for Health and Care Excellence
1.8 Disease-modifying therapies
Multiple sclerosis in adults: management. NICE guideline, NG220, published June 2022
Full text (link is external)
This information has been developed by the MS Trust Health Information team. Our team produces accurate evidence-based information to help you navigate your every day – working alongside health professionals.
We would like to thank Dr Wallace Brownlee, Consultant Neurologist and Clinical Lead for MS, University College London Hospitals NHS Trust, Laura Carrington, MS Clinical Nurse Specialist, Leeds Teaching Hospital NHS Trust and Rachel Dorsey-Campbell, Consultant Pharmacist, Neurology, Imperial College Healthcare NHS Trust, for checking the clinical accuracy of this information.
