A newer class of disease-modifying therapies (DMTs) known as sphingosine-1-phosphate receptor modulators have a unique mechanism of action that makes them particularly useful for treating relapsing forms of multiple sclerosis. For those considering taking an S1P receptor modulator, it can be helpful to know what to expect.
There are now several S1P receptor modulators approved by the U.S. Food and Drug Administration (FDA) to treat MS. Drugs in this category include:
More S1P receptor modulators are currently being studied for their potential safety and efficacy in treating relapsing forms of MS.
Before starting an S1P receptor modulator, your neurologist will likely order specific tests. These will check for any abnormalities that may make S1P modulators less safe for you to take. The Cleveland Clinic recommends that, prior to starting treatment with an S1P modulator such as Mayzent, you should consider all of the tests below.
In a small portion of individuals who have taken S1P modulators, bradycardia (slowing of the heart rate) can occur. An electrocardiogram (EKG), performed by attaching wires to the skin, can confirm that you have a normal heart rhythm and electrical activity.
A thorough eye exam can screen for macular edema, a type of swelling. Macular edema is a rare complication associated with S1P receptor modulator treatment.
CYP2C9 is a protein involved in the body’s metabolization and processing of drugs. A person’s genetic pattern for this protein, obtained via a blood test, determines the titration and dosage of an S1P receptor modulator. People with some genotypes should not take S1P receptor modulators at all, so the results from this test may indicate you are not a good candidate for a drug in this category.
A complete blood count, or CBC, is a common blood test that can screen for many problems, including infections and blood cell disorders. The Cleveland Clinic recommends individuals with MS do not start an S1P receptor modulator if they have any active infections.
Liver function tests, performed using blood samples, determine whether your liver is working properly. S1P receptor modulators are metabolized by the liver.
The varicella zoster virus causes chickenpox and shingles. If your blood tests negative for the antibodies associated with varicella zoster, your doctor may recommend you be vaccinated against this virus prior to starting treatment with an S1P receptor modulator.
If you are switching from an injected drug you take once a week (or less frequently) to an oral drug taken daily, there are some steps to help with this transition. Consider the following strategies to stay on schedule with a daily medication:
For S1P receptor modulators and other disease-modifying therapies to be effective, they must be taken at the correct dosage and frequency, every time, as directed.
As a class, S1P receptor modulators have been associated with rare but potentially serious side effects. These include:
Your doctor may recommend monitoring when first starting an S1P receptor modulator if you have a history of myocardial infarction (heart attack), heart failure, or bradycardia. Otherwise, monitoring may not be required. Whenever you start a new medication, it is important to report all side effects to your doctor right away.
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