Idelvion is used to treat or prevent bleeding in people with hemophilia B. This medication is not for treating people with hemophilia A factor VIII deficiency.

Idelvion may also be used for purposes not listed in this medication guide.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

You may receive your first dose in a hospital or clinic setting to quickly treat any serious side effects.

Idelvion is given as an infusion into a vein. A healthcare provider will give your first dose and may teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Idelvion must be mixed with a liquid (diluent) before using it. When using injections by yourself, be sure you understand how to properly mix and store the medicine.

The mixture should appear clear, yellow, or colorless. Prepare an injection only when you are ready to give it. Do not use if the medicine looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.

Gently swirl but do not shake the medicine while mixing or you may ruin the medicine. Use the injection within 3 hours after mixing your dose.

You may need frequent blood tests.

In case of emergency, wear or carry medical identification to let others know you have a bleeding disorder.

Carefully follow directions on your medicine label about how to store the powder medicine and the diluent. Some forms of coagulation factor IX can be stored at room temperature, and others should be kept in a refrigerator. Do not freeze. Avoid exposing the medication to light.

Each vial (bottle) is for one use only. Throw it away after one use, even if there is still medicine left inside.

Throw away any leftover Idelvion once the expiration date on the label has passed.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

You should not use Idelvion if:

• you have had an allergic reaction to clotting factor medicine;

• you have signs of excessive blood clotting; or

• you are allergic to hamster proteins.

Tell your doctor if you have ever had:

• kidney disease;

• liver disease;

• coronary artery disease (hardening of the arteries); or

• a heart attack or stroke.

Tell your doctor if you are pregnant or breastfeeding.

Idelvion is made from donated human plasma and may contain viruses or other infectious agents. Donated plasma is tested and treated to reduce the risk of contamination, but there is still a small possibility it could transmit disease. Ask your doctor about any possible risk.

Call your doctor for instructions if you miss a dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Get emergency medical help if you have signs of an allergic reaction: hives, itching; wheezing, tightness in your chest, difficult breathing, fast heartbeats, blue lips, feeling like you might pass out; swelling of your face, lips, tongue, or throat.

Idelvion may cause serious side effects. Call your doctor at once if you have:

• weight gain, swelling in your waist, hands, or lower legs;

• loss of appetite;

• fever or chills;

• continued bleeding after treatment;

• new or worsened bleeding; or

• signs of excessive blood clotting--sudden numbness or weakness (especially on one side of the body), slurred speech, problems with vision or balance, chest pain, coughing up blood, or pain, swelling, warmth and redness in one or both legs.

Common side effects of Idelvion may include:

• nausea;

• headache;

• dizziness;

• altered sense of taste;

• mild skin rash; or

• pain, redness, itching, stinging, or other irritation where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Other drugs may affect Idelvion, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.