This medication is used to treat a certain blood disorder (paroxysmal nocturnal hemoglobinuria). This disorder can cause a decrease in red blood cells (anemia). This medication helps to block the decrease in red blood cells and can improve the symptoms of anemia (such as tiredness, shortness of breath) and decrease the need for blood transfusions.

This medication may also be used to treat a certain immune system disorder (atypical Hemolytic Uremic Syndrome). It helps to prevent blood clots caused by this disorder.

Eculizumab is also used to treat a certain muscle condition (generalized Myasthenia Gravis). It may help to improve symptoms of this condition (such as difficulty swallowing, trouble breathing).

Eculizumab is also used to treat a certain nervous system disorder that affects the spinal cord and eye nerve (neuromyelitis optica spectrum disorder). It may help to reduce the number of hospital stays due to the disease.

Read the Medication Guide provided by your pharmacist before you start using eculizumab and each time you get an infusion. Carry the Patient Safety Card with you at all times during treatment and for 3 months after your last dose of eculizumab. If you have any questions, consult your doctor or pharmacist.

This medication is given by injection into a vein by a health care professional as directed by your doctor. It is usually given every 7 days for 5 weeks, then every 14 days. The dosage is based on your medical condition. Children's dosage is also based on weight.

Infusion reactions may happen during the infusion of this drug. Tell your doctor right away if you have any symptoms of infusion reactions such as shortness of breath, chest pain/tightness, dizziness, or feeling faint.

Do not stop receiving this medication without consulting your doctor. Your condition may become worse when the drug is stopped. If you do stop receiving the medication, you may need to be monitored by your doctor for at least 8 or 12 weeks to make sure that your condition does not worsen. Consult your doctor for more details and for symptoms to watch out for.

Tell your doctor if your condition does not get better or if it gets worse.

See also Warning and How to Use sections.

Headache, diarrhea, nausea, or vomiting may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• signs of infection (such as cough/sore throat that doesn't go away, fever, painful/frequent urination)
• swelling hands/ankles/feet
• fast heartbeat
• signs of kidney problems (such as change in the amount of urine)

If you have used a similar medication recently (C5 inhibitors such as crovalimab, ravulizumab), you may be at increased risk for other immune system problems. Tell your doctor right away if you have symptoms such as:

• joint/muscle/bone pain
• numbness/tingling of the hands/feet
• unusual tiredness/weakness
• stomach/abdominal pain

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using eculizumab, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• current/recent infection (especially of meningitis)

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Eculizumab can make you more likely to get certain infections (such as gonorrhea). Talk to your doctor for more details.

Tell your doctor your vaccine history and ask if you need to get any vaccines before starting treatment with this medication. Tell your health care professional that you are using eculizumab before having any immunizations/vaccinations. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as LDH levels, kidney function, complete blood count, blood pressure) should be done while you are using this medication and for 8 or 12 weeks after stopping treatment. Keep all medical and lab appointments. Consult your doctor for more details.

It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule.

Not applicable. This medication is given in a clinic and will not be stored at home.

Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).