Antihemophilic factor (factor VIII) is a naturally occurring protein in the blood that helps blood to clot. A lack of factor VIII is the cause of hemophilia A.

Antihemophilic factor (factor VIII) is used to treat or prevent bleeding in people with hemophilia A.

Antihemophilic factor (factor VIII) may also be used for purposes other than those listed in this medication guide.

This medication is given as an injection through a needle placed into a vein. Your doctor, nurse, or other healthcare provider will give your first injection. Then you will be given instructions on how to use your injections at home. Do not use this medicine at home if you do not fully understand how to give the injection and properly dispose of needles and other items used in giving the medicine.

To be sure this medication is helping your condition, your blood will need to be tested on a regular basis. Do not miss any scheduled visits to your doctor.

Carry an ID card or wear a medical alert bracelet stating that you have hemophilia, in case of emergency. Any doctor, dentist, or emergency medical care provider who treats you should know that you have a bleeding disorder.

Your body may develop antibodies to this medication, making it less effective. Contact your doctor if this medicine does not seem to be working as well as before in controlling your bleeding.

If you need to have any type of surgery, tell the surgeon ahead of time that you are using antihemophilic factor (factor VIII). You may need to stop using the medicine for a short time.

Store the powder medicine in the refrigerator. Do not freeze.

Do not mix this medicine with the liquid diluent until you are ready to give the injection. Once the medicine has been mixed, you must use it within 3 hours. Do not refrigerate the mixed medicine. Keep it at room temperature.

You may also store the powder at room temperature for up to 6 months or until the expiration date printed on the label (whichever comes first).

Do not put the medicine back into the refrigerator once you have kept it at room temperature.

Other drugs that affect bleeding or blood-clotting may interact with antihemophilic factor (factor VIII) and cause dangerous side effects or make the medicine less effective.

There may be other drugs that can affect antihemophilic factor (factor VIII). Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

There are no restrictions on food, beverages, or activity while using this medication unless your doctor has told you otherwise.

Seek emergency medical attention if you think you have used too much of this medicine.

Contact your doctor for instructions if you miss a dose of this medication.

Some forms of this medication are made from human plasma (part of the blood) and may contain viruses and other infectious agents that can cause disease. Although donated human plasma is screened, tested, and treated to reduce the risk of it containing anything that could cause disease, there is still a small possibility it could transmit disease. Talk with your doctor about the risks and benefits of using this medication.

Some viruses, such as parovovirus B19 and hepatitis A, may be more difficult to identify or remove from antihemophilic factor (factor VIII). Parovovirus can seriously affect pregnant women and people with weak immune systems. Symptoms of parovovirus B19 infection include fever, chills, runny nose, and drowsiness followed about 2 weeks later by a rash and joint pain. Symptoms of hepatitis A may include several days to weeks of poor appetite, tiredness, and low-grade fever followed by nausea, vomiting, and stomach pain. Dark-colored urine and jaundice (yellowing of the skin or eyes) may also occur. Contact your doctor if you develop any of these symptoms after treatment with antihemophilic factor (factor VIII).

Carry an ID card or wear a medical alert bracelet stating that you have hemophilia, in case of emergency. Any doctor, dentist, or emergency medical care provider who treats you should know that you have a bleeding disorder.

Your body may develop antibodies to this medication, making it less effective. Contact your doctor if this medicine does not seem to be working as well as before in controlling your bleeding.

If you need to have any type of surgery, tell the surgeon ahead of time that you are using antihemophilic factor (factor VIII). You may need to stop using the medicine for a short time.

This medication comes in many different strengths. Be sure the strength printed on the medicine bottle label is correct for the dose your doctor has prescribed for you.

Do not use this medication if you have:

• a history of allergy to antihemophilic factor; or

• a history of allergy to products made with human or animal proteins, especially mouse proteins.

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

It is not known whether this medication passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

Some forms of this medication are made from human plasma (part of the blood) and may contain viruses and other infectious agents that can cause disease. Although donated human plasma is screened, tested, and treated to reduce the risk of it containing anything that could cause disease, there is still a small possibility it could transmit disease. Talk with your doctor about the risks and benefits of using this medication.

Some viruses, such as parovovirus B19 and hepatitis A, may be more difficult to identify or remove from antihemophilic factor (factor VIII). Parovovirus can seriously affect pregnant women and people with weak immune systems. Symptoms of parovovirus B19 infection include fever, chills, runny nose, and drowsiness followed about 2 weeks later by a rash and joint pain. Symptoms of hepatitis A may include several days to weeks of poor appetite, tiredness, and low-grade fever followed by nausea, vomiting, and stomach pain. Dark-colored urine and jaundice (yellowing of the skin or eyes) may also occur. Contact your doctor if you develop any of these symptoms after treatment with antihemophilic factor (factor VIII).

Your pharmacist has additional information about antihemophilic factor (factor VIII) written for health professionals that you may read.

Antihemophilic factor (factor VIII) is available with a prescription under several brand names. Generic formulations may also be available. Ask your pharmacist any questions you have about this medication, especially if it is new to you.