Etrasimod belongs to the class of medications called sphingosine 1- phosphate (S1P) receptor modulators. It is used to treat moderate-to-severely active ulcerative colitis (UC). It is used when other treatments have not been effective or tolerated, or if previous treatments are becoming less effective.

UC may be caused by the body's immune system mistaking tissues in the digestive system as not belonging. The immune system causes white blood cells to be released into the blood, attacking the digestive system in defense, and contributing to the inflammation that causes symptoms of ulcerative colitis. Etrasimod works by lowering the number of white blood cells (lymphocytes) in the blood by preventing them from moving freely through the body, thereby reducing the immune response and symptoms of UC.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The usual adult dose of etrasimod is 2 mg taken by mouth, once a day. The tablet may be taken with or without food and swallowed whole with some fluids.

The first dose of etrasimod is taken in your doctor's office or clinic. You will need to stay at the office for at least 4 hours after the first dose. This will allow the doctor to monitor for side effects such as slowed heartbeat and treat any problems before they become an emergency.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

If you have been taking this medication for less than 1 week and you forget to take a dose for 2 days or more, or if you stop taking etrasimod for more than 7 days after 1 or more weeks of treatment, contact your doctor as soon as possible. Your doctor may want to monitor you for heart and blood pressure effects before you restart the medication.
Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Each green, round, film-coated tablet, debossed with "ETR" on one side and "2" on the other side, contains 2 mg of etrasimod, as etrasimod L-arginine. Nonmedicinal ingredients: magnesium stearate, mannitol, microcrystalline cellulose, and sodium starch glycolate; green film coat: FD&C Blue #1/brilliant blue FCF aluminum lake, FD&C Blue #2/indigo carmine aluminum lake, FD&C Yellow #5/tartrazine aluminum lake, macrogol 4000 JP//PEG3550, polyvinyl alcohol (partially hydrolyzed), talc, and titanium dioxide.

Do not take this medication if you:

• are allergic to etrasimod or any ingredients of the medication
• have a severe active infection or an active chronic infection such as hepatitis or tuberculosis
• have a weakened immune system due to disease (e.g., immunodeficiency syndrome) or use medicines or treatments that suppress the immune system (e.g., to treat cancer or bone marrow transplantation)
• have an active cancer
• have had a heart attack, unstable angina, a transient ischemic attack, (mini-stroke), or heart failure in the past 6 months
• have heart block or sick-sinus syndrome and do not have a pacemaker
• are or may become pregnant and are not using effective birth control
• are breast-feeding

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• dizziness
• flu-like symptoms (sudden lack of energy, fever, cough, sore throat)
• headache
• nausea

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• high cholesterol
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• symptoms of high blood pressure (e.g., blurred vision, lightheadedness, feeling short of breath, measured high blood pressure, headache, or nosebleeds)
• symptoms of decreased white blood cells (e.g., fever, cough, mouth sores, increased frequency of infections)
• symptoms of irregular heartbeat (e.g., chest pain, dizziness, rapid or pounding heartbeat, shortness of breath)
• symptoms of macular edema (swelling in the central vision area of the retina at the back of the eye) such as shadows or blind spots in the centre of your vision, blurred vision, or problems seeing colours or details
• symptoms of a slow heartbeat (e.g., dizziness, fatigue, decreased blood pressure)
• symptoms of a urinary tract infection (e.g. pain when urinating, urinating more often than usual, low back or flank pain)
• trouble breathing
• unusual growths on the skin (e.g., shiny, raised growths or purple, red, or brown blotches)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• symptoms of leukoencephalopathy (e.g., seizures, vision loss, trouble thinking clearly, difficulty walking)
• symptoms of posterior reversible encephalopathy syndrome (e.g., headache, seizures, weakness, confusion, high blood pressure, vision changes, difficulty thinking clearly)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Blood pressure: Etrasimod may also increase blood pressure and is not recommended for people who have uncontrolled high blood pressure. If you have high blood pressure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Breathing disorders: Etrasimod may affect lung function. People with respiratory problems such as pulmonary fibrosis, asthma, and chronic obstructive pulmonary disease may be at an increased risk of experiencing worsening breathing problems. If you have respiratory problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Contact your doctor if you experience any new or worsening shortness of breath.

Cancer: Etrasimod reduces the number of cells that fight infection in the body (white blood cells). This may increase your risk of developing infections and certain types of cancer, particularly skin cancer.

While you are taking etrasimod, it is important to limit your exposure to the sun and use appropriate sun protection such as sunscreen and protective clothing. Let your doctor know if you notice changes to your skin, such as thickening, warts, sores or bumps that do not heal. Your doctor will monitor you for skin cancer while you are taking this medication. Talk to your doctor if you have any concerns.

Dizziness/reduced alertness: Etrasimod may cause dizziness, affecting your ability to drive or operate machinery. Avoid driving, operating machinery, or performing other potentially hazardous tasks until you have determined how you are affected by this medication.

Eye problems: People who have diabetes or a history of inflammation of the middle of the eye are at an increased risk of developing swelling in the macula of the eye. It is recommended that you have an eye examination after taking this medication for 3 or 4 months to check for changes in your eyes that have not caused symptoms. Report any changes in vision to your doctor as soon as possible.

Heart problems: Etrasimod causes a decrease in heart rate a few hours after taking the first dose. Your doctor will want to check your heart before you start this medication. You will also need to be observed in a doctor's office or clinic for 4 hours after your first dose. This allows the doctor to monitor your heart rate and treat any problems before they become an emergency. It may be necessary to be monitored for a longer period of time if you develop very low heart rate or an arrhythmia. People with certain heart conditions such as heart arrhythmias, angina, congestive heart failure or a history of heart attack, should not take etrasimod.

If you have a heart problem, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Heart rhythm: This medication can cause changes to the normal rhythm of the heart, including an irregular heartbeat called QT prolongation. QT prolongation is a serious life-threatening condition that can cause fainting, seizures, and sudden death. If you are at risk for heart rhythm problems (e.g., people with heart failure, angina, or low heart rate), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Infections: Etrasimod works by decreasing the number of white blood cells in the blood stream. White blood cells are responsible for fighting infection in the body. As a result, people taking etrasimod may have an increased risk of infections. If you notice signs of an infection, such as fever, redness, or swelling, contact your doctor as soon as possible. Rarely, people taking etrasimod have experienced life-threatening infections caused by varicella zoster (chicken pox, shingles) and herpes simplex viruses.

Liver function: Liver disease or reduced liver function may cause etrasimod to build up in the body, causing side effects. This medication may also reduce liver function. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Progressive multifocal leukoencephalopathy (PML): Although there have been reports of PML after using etrasimod, it has been reported with the use of other medication sin the same class. PML is a rare viral infection that causes nerve damage in the brain. If you experience memory loss, vision changes, trouble thinking, personality changes or difficulty walking, contact your doctor immediately.

Posterior Reversible Encephalopathy Syndrome (PRES): This is a rare disease of the brain that has been reported with the use of other medication in the same class as etrasimod. If you have had a previous episode of PRES, this may not be an appropriate medication for you. Make sure your doctor knows you have experienced this before. If you experience signs and symptoms of PRES, such as headache, nausea, vomiting, seizures, change in awareness or consciousness, or vision changes, contact your doctor immediately.

Vaccines: While taking etrasimod, and for up to 2 weeks after stopping treatment, some vaccines containing live viruses may result in the infection that the vaccination should prevent, while other vaccines may not work well enough to protect you. Talk to your doctor about which vaccinations you need before starting treatment, and which vaccines to avoid during treatment. Any required vaccination should be received at least 4 weeks before starting etrasimod.

Pregnancy: This medication may cause harm to an unborn fetus and should not be used during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately. If you are taking etrasimod and could become pregnant, you should use an effective method of birth control (e.g., birth control pill, condoms) during treatment, and for at least 6 days after stopping treatment with etrasimod.

Breast-feeding: It is not known if etrasimod passes into breast milk. If you are breast-feeding and taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children.

For a full list of interactions, use the Drug Interaction Checker available on the Drugs.com website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.