Qfitlia Prefilled Pen

Generic name: fitusiran [ FIT-ue-SIR-an ]
Brand names: Qfitlia, Qfitlia Prefilled Pen
Drug class: Miscellaneous coagulation modifiers

Medically reviewed by Drugs.com on May 5, 2025. Written by Cerner Multum.

What is Qfitlia Prefilled Pen?

Qfitlia Prefilled Pen is used in adults and children at least 12 years old with hemophilia A or B to help prevent bleeding episodes or make them occur less often.

Your doctor will make sure you can be treated with Qfitlia Prefilled Pen.

Qfitlia Prefilled Pen may also be used for purposes not listed in this medication guide.

Qfitlia Prefilled Pen side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Seek medical help right away if you show signs of a blood clot such as sudden numbness or weakness (especially on one side of the body), severe headache, confusion, vision changes, slurred speech, chest pain, shortness of breath, fast heart rate, dizziness, coughing up blood, or pain, swelling, or warmth in arms or legs.

Qfitlia Prefilled Pen may cause serious side effects. Call your doctor at once if you have:

• liver problems--loss of appetite, nausea, vomiting, stomach pain (upper right side), tiredness, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or

• gallbladder problems--stomach pain after eating, nausea, vomiting, heartburn, bloating, and severe upper stomach pain that may spread to your back.

Common side effects of Qfitlia Prefilled Pen may include:

• bacterial or viral infections; or

• cold symptoms such as stuffy nose, sneezing, sore throat.

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.

Related/similar drugs

Warnings

Using Qfitlia Prefilled Pen can increase your risk of blood clots especially if you have certain medical conditions or you also use other medicines to help treat blood clots.

Qfitlia Prefilled Pen can increase your risk of gallbladder disease. Call your doctor right away if you have unexplained stomach pain, nausea, vomiting, or heartburn.

Before taking this medicine

Tell your doctor if you have or have ever had:

• blood clots or any other blood clotting disorder;

• gallbladder disease; or

• liver disease.

It is not known if Qfitlia Prefilled Pen will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Using Qfitlia Prefilled Pen with certain hormonal birth controls can increase your risk of blood clots. Use barrier birth control to prevent pregnancy: condom, diaphragm, cervical cap, or contraceptive sponge. Ask your doctor if you have any questions.

Ask a doctor if it is safe to breastfeed while using this medicine.

Do not allow a child to use Qfitlia Prefilled Pen without help from an adult.

How should I use Qfitlia Prefilled Pen?

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.

Tell your doctor if you are using other treatments to help protect against bleeding. Your healthcare provider will provide instructions for stopping your current treatment when switching to Qfitlia Prefilled Pen.

Qfitlia Prefilled Pen is injected under the skin. Your healthcare provider will show you or your caregiver where to inject this medicine. Your doctor will determine your treatment schedule.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand how to use an injection.

Prepare an injection only when you are ready to give it. Call your pharmacist if the medicine looks cloudy, has changed colors or has particles in it.

Do not inject within 2 inches of your navel, or areas where the skin is tender, damaged, scaly, has bruises, scars, or visible veins. Do not inject into the same place two times in a row.

Throw away after one use, even if there is still medicine left inside.

Your blood may need to be tested often before and during treatment. Your doctor will need to check your progress on a regular basis.

You may be given other medicines to treat unexpected bleeding during treatment with Qfitlia Prefilled Pen. Follow your doctor's instructions very carefully.

Your condition may get worse if you stop using Qfitlia Prefilled Pen suddenly. Ask your doctor before stopping the medicine.

Call your doctor if your symptoms do not improve, or if they get worse.

Store Qfitlia Prefilled Pen in the original container in the refrigerator. Protect from light and do not freeze or shake the medicine.

Take the medicine out of the refrigerator and let it reach room temperature before using. Do not warm the medicine with hot water, sunlight, or a microwave.

You may store Qfitlia Prefilled Pen at room temperature. Certain formulations may only be stable for a limited number of months after being removed from the refrigerator. Throw away any medicine not used within that time. Talk to your pharmacist if you have any questions.

What happens if I miss a dose?

Use the medicine as soon as you remember, and then go back to your regular schedule. Do not use two doses at one time.

What happens if I overdose?

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

What should I avoid while taking Qfitlia Prefilled Pen?

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

What other drugs will affect Qfitlia Prefilled Pen?

Other drugs may affect Qfitlia Prefilled Pen, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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