Fosamprenavir

Generic name: fosamprenavir [ FOS-am-PREN-a-veer ]
Brand names: Lexiva, Telzir
Dosage form: oral tablet (700 mg)
Drug class: Protease inhibitors

Medically reviewed by Drugs.com on Oct 28, 2024. Written by Cerner Multum.

What is fosamprenavir?

Fosamprenavir is an antiviral medicine that prevents human immunodeficiency virus (HIV) from multiplying in your body.

Fosamprenavir is used to treat HIV, the virus that can cause acquired immunodeficiency syndrome (AIDS). Fosamprenavir is for use in adults and children who are at least 4 weeks old. fosamprenavir is not a cure for HIV or AIDS.

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

Fosamprenavir side effects

Get emergency medical help if you have signs of an allergic reaction (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Stop taking fosamprenavir and call your doctor at once if you have:

• pale or yellowed skin, dark colored urine, fever, confusion or weakness;

• increased urination or extreme thirst; or

• high blood sugar--increased thirst, increased urination, dry mouth, fruity breath odor; or

• symptoms of kidney stones--sudden and severe pain in your lower back or side, blood in your urine, pain or burning when you urinate.

Fosamprenavir affects your immune system, which may cause certain side effects (even weeks or months after you've taken this medicine). Tell your doctor if you have:

• signs of a new infection--fever, night sweats, swollen glands, cold sores, cough, wheezing, diarrhea, weight loss;

• trouble speaking or swallowing, problems with balance or eye movement, weakness or prickly feeling; or

• swelling in your neck or throat (enlarged thyroid), menstrual changes, impotence.

Common side effects of fosamprenavir may include:

• fever or other signs of infection;

• nausea, vomiting, diarrhea;

• rash;

• headache; or

• changes in the shape or location of body fat (especially in your arms, legs, face, neck, breasts, and waist).

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

Tell your doctor about all your current medicines and any you start or stop using. Many drugs can interact, and some drugs should not be used together.

Before taking this medicine

You should not use fosamprenavir if you are allergic to it.

Some medicines can cause unwanted or dangerous effects when used with fosamprenavir. Your doctor may change your treatment plan if you also use:

• alfuzosin;

• delavirdine;

• rifampin;

• St. John's wort;

• sildenafil (Revatio) when used to treat pulmonary arterial hypertension (PAH);

• antipsychotic medicine--lurasidone, pimozide;

• cholesterol-lowering medicine--lovastatin, simvastatin;

• ergot medicine--dihydroergotamine, ergotamine, ergonovine, methylergonovine;

• heart rhythm medicine--flecainide, propafenone; or

• a sedative--oral midazolam or triazolam.

Tell your doctor if you have ever had:

• liver disease, including hepatitis B or C;

• kidney disease;

• a bleeding disorder such as hemophilia;

• diabetes; or

• an allergy to sulfa drugs.

Tell your doctor if you are pregnant, and use your medications properly to control your infection. HIV can be passed to your baby if the virus is not controlled during pregnancy. Your name may be listed on a registry to track any effects of antiviral medicine on the baby.

Fosamprenavir can make birth control pills less effective. Taking fosamprenavir together with ritonavir and also using birth control pills can increase your risk of abnormal liver function tests. Ask your doctor about using non hormonal birth control (condom, diaphragm with spermicide) to prevent pregnancy.

Women with HIV or AIDS should not breast-feed a baby. Even if your baby is born without HIV, the virus may be passed to the baby in your breast milk.

Fosamprenavir should not be given to an infant younger than 4 weeks (28 days) old.

How should I take fosamprenavir?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Fosamprenavir tablets can be taken with or without food.

Fosamprenavir liquid should be taken with food in children and without food in adults.

Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Fosamprenavir doses are based on weight in children. Your child's dose needs may change if the child gains or loses weight.

You will need frequent medical tests.

Use all HIV medications as directed and read all medication guides you receive. Do not change your dose or dosing schedule without your doctor's advice. Every person with HIV should remain under the care of a doctor.

Store fosamprenavir tablets at room temperature away from moisture and heat.

You may store fosamprenavir liquid in the refrigerator but do not allow it to freeze.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Get your prescription refilled before you run out of medicine completely.

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 fosamprenavir?

Using fosamprenavir will not prevent your disease from spreading. Do not have unprotected sex or share razors or toothbrushes. Talk with your doctor about safe ways to prevent HIV transmission during sex. Sharing drug or medicine needles is never safe, even for a healthy person.

What other drugs will affect fosamprenavir?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Many drugs can affect fosamprenavir, and some drugs should not be used at the same time. Tell your doctor about all your current medicines and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.

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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