Fingolimod (Gilenya) is a medication taken by mouth to treat symptoms of relapsing-remitting multiple sclerosis (RRMS). It helps make the symptoms of RRMS occur less often. These symptoms can include:

  • muscle spasms
  • weakness and numbness
  • bladder control problems
  • problems with speech and vision

Fingolimod also works to delay physical disability that can be caused by RRMS.

As with all drugs, fingolimod can cause side effects. In rare cases, they can be serious.

Learn more: RRMS causes, symptoms, and treatments »

You take the first dose of fingolimod in your doctor’s office. After you take it, you’re monitored for six or more hours. An electrocardiogram (ECG) is also done before and after you take the medication to check your heart rate.

Healthcare professionals take these precautions because your first dose of fingolimod can cause certain side effects. These include low blood pressure and bradycardia, a slowed heart rate that can be dangerous. Signs of a slowed heart rate can include:

  • sudden tiredness
  • dizziness
  • chest pain

These effects may occur with your first dose, but they should not occur every time you take fingolimod. If you have these symptoms at home after your second dose, call your doctor right away.

Fingolimod is taken once per day. The more common side effects that can occur after the second and other follow-up doses can include:

  • diarrhea
  • coughing
  • headaches
  • hair loss
  • depression
  • muscle weakness
  • dry and itchy skin

Fingolimod can also cause more serious side effects. These side effects generally go away if you stop taking the drug. Other than liver problems, which can be common, these side effects tend to be rare. Serious side effects can include:

Liver problems: Your doctor will likely do regular blood tests during your treatment to check for liver problems. Symptoms of liver problems can include jaundice, which causes yellowing of the skin and the whites of the eyes.

Increased risk of infections: Fingolimod reduces the number of lymphocytes in your body. These are white blood cells that cause some of the nerve damage from MS. However, these cells also help your body fight infections. So, with fewer lymphocytes in your body, your risk of infection increases. This effect can last for up to two months after you stop taking fingolimod.

Macular edema: With this condition, fluid builds up in the macula, which is part of the eye’s retina. Symptoms can include blurry vision, a blind spot, and seeing unusual colors. Your risk of this condition is higher if you have diabetes.

Trouble breathing: Shortness of breath can occur if you take fingolimod.

Increased blood pressure: Your doctor will likely monitor your blood pressure during your treatment with fingolimod.

Leukoencephalopathy: In rare cases, fingolimod can cause brain problems. These include progressive multifocal leukoencephalopathy (PML) and posterior encephalopathy syndrome (PRES). Symptoms can include changes in thinking, decreased strength, and headache. Tell your doctor right away if you have these symptoms. Your doctor may stop your treatment with fingolimod.

Cancer: Basal cell carcinoma, a type of skin cancer, has been linked with fingolimod use. While using this drug, you and your doctor should watch for unusual bumps or growths on your skin.

Allergic reaction: Like many drugs, fingolimod can cause an allergic reaction. Symptoms can include swelling, rash, and hives. If you know you’re allergic to fingolimod, you should not take this drug.

Severe reactions to fingolimod are rare. The FDA reported a death in 2011 linked to a first use of fingolimod. Other instances of death from heart problems have also been reported in people taking fingolimod. That said, the FDA has not found a direct link between these other deaths and the use of fingolimod.

Still, as a result of these problems, the FDA has changed its guidelines for fingolimod use. It now states that people who take certain antiarrhythmic drugs or who have a history of heart conditions or stroke should not take fingolimod.

The FDA has also reported possible cases of a rare brain infection called progressive multifocal leukoencephalopathy (PML) after fingolimod use.

These reports may sound scary, but keep in mind that most severe problems with fingolimod are rare. If you have concerns about using this drug, be sure to discuss them with your doctor. If you’ve already been prescribed this drug, don’t stop taking it unless your doctor tells you to.

Fingolimod can cause problems if you have certain health conditions. Before taking fingolimod, be sure to tell your doctor if you have:

  • arrhythmia (irregular or abnormal heartbeat)
  • history of stroke
  • heart problems, including heart attack or angina (chest pain)
  • history of repeated fainting
  • fever or infection
  • a disease that impairs your immune system, such as HIV or leukemia
  • history of chicken pox or the chicken pox vaccine
  • eye problems, including a condition called uveitis
  • diabetes
  • breathing problems, including during sleep
  • liver problems
  • high blood pressure
  • basal cell carcinoma, a type of skin cancer
  • thyroid disease
  • low levels of calcium, sodium, or potassium

Fingolimod can interact with many different drugs. An interaction can cause health problems or make either drug work less well. Tell your doctor about all medications, vitamins, and supplements you take, especially ones known interact with fingolimod. A few examples of these drugs include:

  • drugs that impair the immune system, including corticosteroids
  • live vaccines
  • drugs that slow your heart rate, such as beta blockers or calcium channel blockers

No cure for MS has yet been found. Therefore, medications such as fingolimod are an important way to improve quality of life and to delay disability for people with RRMS.

You and your doctor can weigh the possible benefits and risks of taking this medication. Questions you may ask your doctor include:

  • Am I at high risk of side effects from fingolimod?
  • Do I take any medications that might interact with this drug?
  • Are there other MS medications that may cause fewer side effects for me?
  • What side effects should I report to you right away if I have them?