Many people with MS switch DMTs at least once — if not many times — throughout their treatment. When switching from one medication to another, doctors may recommend a “wash-out period” in which you stop taking one drug and wait for a designated period of time before starting another.
Wash-out periods come with risks and benefits. Continue reading to learn about eight things to consider when planning for a wash-out period.
If you are living with MS, you will likely consider undergoing a medication change at some point.
In one study in which more than 110,000 people with MS tried nearly 270,000 DMTs, researchers found that these medications were discontinued about 68.2 percent of the time during the first two years of treatment. You might stop taking a DMT if:
In these situations, you and your doctor may decide you should stop taking your DMT, undergo a wash-out period, and then try a new DMT.
Read more about signs it may be time to switch DMTs.
The main purpose of a wash-out period is to help you avoid experiencing unpleasant side effects from multiple medications at once.
DMTs may stay in your system for a little while before they are fully cleared away, so if you take one DMT one day and a different DMT the next, both medications may be still be in your body at the same time. This could cause the drugs to interact or create worse side effects than usual.
A major downside of going through a wash-out period is that your MS may not be completely under control and may flare up. For people with relapsing forms of MS including relapsing-remitting MS, clinically isolated syndrome, and active secondary progressive MS, flares are periods of new or worsening symptoms.
Your doctor may recommend regular follow-up testing during a wash-out period to look for early signs of flares. They may measure your levels of lymphocytes (white blood cells) or use an MRI to look for lesions (areas of your nervous system that show damage).
If you experience flares during a wash-out period, you may be able to take other medications such as intravenous (through a vein) steroids. These other treatments may help control symptoms until your new DMT takes effect.
Once you start taking a new DMT after a wash-out period, it will take some time for the new drug to start fully working. You won’t know how effective the new treatment is until three to six months after you start using it.
In many cases, researchers have not conducted clinical trials to specifically calculate how long a wash-out period should be. However, experts have shared general guidelines for different DMTs based on how these medications affect the body:
For medications that work by binding to the cell receptor CD20, such as ofatumumab (Kesimpta), some experts recommend skipping a wash-out period. Minimizing the time between the stopping the older drug and starting the newer drug may help prevent MS from becoming more active.
Medications like teriflunomide (Aubagio) may take up to two years to be cleared out of your body. However, your doctor may speed up this process by prescribing medications such as cholestyramine (Prevalite) or activated charcoal for 11 days.
Your doctor may recommend a longer or shorter wash-out period based on your health details and their experience and knowledge about a specific DMT.
Other factors can also help determine how long your wash-out period is.
When deciding on the length of your wash-out period, your doctor may also consider how active your MS is, your other health conditions, and your reason for switching DMTs.
Work with your doctor to weigh the risks and benefits of different wash-out period lengths. Only your doctor — who understands your values and health factors — can help you decide how to approach a wash-out period.
Most of the research and guidelines surrounding MS wash-out periods assume that people will stop taking a DMT all at once. However, some doctors may suggest that you taper off a drug by gradually decreasing your dose over time.
One study among people with MS on natalizumab treatment found that those who tapered off the DMT were less likely to experience a disease flare. Some experts also suggest tapering off fingolimod. However, tapering before a wash-out period has not been studied for most DMTs, so it’s unclear whether this strategy may help reduce relapse rates or lead to a higher risk of flares.
You may also need to undergo a wash-out period if you want to become pregnant. There haven’t been many studies about whether certain DMTs are safe to use during pregnancy or whether they can harm a developing baby. Therefore, experts usually recommend that those who want to get pregnant go through a wash-out period before they conceive.
How long the wash-out period should last depends on the DMT, although your doctor may also make other recommendations. Some recommended guidelines state:
In some cases, your doctor may also suggest a wash-out period if you need to undergo treatment for a different health condition. Talk to your neurologist if you’re not sure whether you should discontinue a DMT.
Make sure to take your DMTs as directed. Skipping medication, decreasing your doses, or taking your medication in ways not directed by your doctor can make your MS worse.
If you’re not happy with your DMT for any reason, talk to your health care team. There are many approved DMTs for MS, and your neurologist can help you switch to a different treatment option that works better for your needs. Your doctor can also help recommend a wash-out period that will keep you safe while minimizing your risk of MS flares.
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