Nusinersen injection is used for the treatment of spinal muscular atrophy (an inherited condition that reduces muscle strength and movement) in infants, children, and adults. Nusinersen injection is in a class of medications called antisense oligonucleotide inhibitors. It works by increasing the amount of a certain protein necessary for the muscles and nerves to work normally.

Nusinersen injection comes as a solution (liquid) to inject intrathecally (into the fluid-filled space of the spinal canal). Nusinersen injection is given by a doctor in a medical office or clinic. It is usually given as 4 initial doses (once every 2 weeks for the first 3 doses and again 30 days after the third dose) and then is given once every 4 months thereafter.

Before taking nusinersen injection,

• tell your doctor and pharmacist if you are allergic to nusinersen, any other medications, or any of the ingredients in nusinersen injection. Ask your pharmacist for a list of the ingredients.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have or have ever had kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while receiving nusinersen injection, call your doctor.
• if you are having surgery, including dental surgery, tell the doctor or dentist that you are receiving nusinersen injection.

If you miss an appointment to receive nusinersen injection, call your doctor right away to reschedule your appointment. Your doctor will probably tell you to resume your previous schedule to receive nusinersen injection, with at least 14 days between the 4 initial doses and 4 months between the later doses.

Unless your doctor tells you otherwise, continue your normal diet.

Nusinersen injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• constipation
• gas
• weight loss
• headache
• vomiting
• back pain
• falling
• runny or stuffed nose, sneezing, sore throat
• ear pain, fever, or other signs of ear infection
• fever

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• unusual bleeding or bruising
• decreased urination; foamy, pink, or brown colored urine; swelling in hands, face, feet or stomach
• frequent, urgent, difficult, or painful urination
• cough, shortness of breath, fever, chills

Nusinersen injection may slow an infant's growth. Your child's doctor will watch his or her growth carefully. Talk to your child's doctor if you have concerns about your child's growth while he or she is receiving this medication.

Nusinersen injection may cause other side effects. Call your doctor if you have any unusual problems while receiving this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain labs before starting treatment, before you receive each dose, and as needed during treatment to check your body's response to nusinersen injection.

Ask your pharmacist any questions you have about nusinersen injection.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.