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Generic Name: fosamprenavir (FOS am PREN a veer)
Brand Names: Lexiva

Medically reviewed on May 14, 2018

What is Lexiva?

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

Lexiva is used to treat HIV, the virus that can cause acquired immunodeficiency syndrome (AIDS).

Lexiva is for use in adults and children who are at least 4 weeks old. This medicine is not a cure for HIV or AIDS.

Important information

Do not take Lexiva together with another HIV medicine called ritonavir if you are also using flecainide or propafenone to treat a heart rhythm disorder. Ask your doctor about taking a different heart rhythm medication during treatment with Lexiva.

Some medicines can cause unwanted or dangerous effects when used with Lexiva. Your doctor may need to change your treatment plan if you use any of the following drugs: alfuzosin, cisapride, delavirdine, lovastatin, simvastatin, midazolam, triazolam, pimozide, rifampin, sildenafil (for treating pulmonary arterial hypertension), St. John's wort, or an ergot medicine (dihydroergotamine, ergotamine, ergonovine, methylergonovine).

Before taking this medicine

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

There are certain medicines that can cause life-threatening drug interactions with Lexiva, and should not be used at the same time. Your doctor may need to change your treatment plan if you use any of the following drugs:

  • alfuzosin;

  • delavirdine;

  • pimozide;

  • rifampin;

  • St. John's wort;

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

  • cholesterol-lowering medicine - lovastatin, simvastatin;

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

  • heart rhythm medicine - flecainide, propafenone; or

  • a sedative - oral midazolam or triazolam.

To make sure Lexiva is safe for you, tell your doctor if you have:

  • liver disease;

  • kidney disease;

  • diabetes;

  • a bleeding disorder such as hemophilia;

  • heart disease, history of heart attack;

  • an allergy to sulfa drugs;

  • high cholesterol or triglycerides; or

  • if you have ever used a protease inhibitor in the past.

It is not known whether Lexiva will harm an unborn baby. However, HIV can be passed to your baby if you are not properly treated during pregnancy. Take all of your HIV medicines as directed to control your infection. Tell your doctor if you become pregnant.

Your name may need to be listed on an antiviral pregnancy registry when you start using this medicine.

Lexiva can make birth control pills less effective. Taking Lexiva 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.

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

How should I take Lexiva?

Take Lexiva exactly as prescribed by your doctor. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Lexiva tablets can be taken with or without food.

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

Shake the oral suspension (liquid) well just before you measure a dose. Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

If a child is using this medicine, tell your doctor if the child has any changes in weight. Lexiva doses are based on weight in children, and any changes may affect your child's dose.

While using Lexiva, you may need frequent blood tests at your doctor's office.

Use Lexiva regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely.

HIV/AIDS is usually treated with a combination of drugs. Use all medications as directed by your doctor. Read the medication guide or patient instructions provided with each medication. Do not change your doses or medication schedule without your doctor's advice. Every person with HIV or AIDS should remain under the care of a doctor.

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

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

See also: Dosage Information (in more detail)

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

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 Lexiva?

Taking this medication will not prevent you from passing HIV to other people. 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.

Lexiva side effects

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

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

  • chest pain or pressure, tight feeling in your neck or jaw, pain spreading to your arm or shoulder;

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

  • increased urination or extreme thirst;

  • sudden and severe pain in your lower back or side, blood in your urine, pain or burning when you urinate; or

  • severe skin reaction - fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Lexiva may increase your risk of certain infections or autoimmune disorders by changing the way your immune system works. Symptoms may occur weeks or months after you start treatment with Lexiva. Tell your doctor if you have:

  • signs of a new infection - fever, night sweats, swollen glands, mouth sores, diarrhea, stomach pain, weight loss;

  • chest pain (especially when you breathe), dry cough, wheezing, feeling short of breath;

  • cold sores, sores on your genital or anal area;

  • rapid heart rate, feeling anxious or irritable, weakness or prickly feeling, problems with balance or eye movement;

  • trouble speaking or swallowing, severe lower back pain, loss of bladder or bowel control; or

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

Common Lexiva side effects 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.

See also: Side effects (in more detail)

What other drugs will affect Lexiva?

Many drugs can interact with fosamprenavir, and some drugs should not be used together. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any you start or stop using, especially:

  • other drugs to treat HIV or AIDS;

  • an antibiotic or antifungal medicine;

  • an antidepressant or anti-psychotic medicine;

  • antiviral medicine to treat hepatitis C;

  • a blood thinner (warfarin, Coumadin, Jantoven);

  • cholesterol-lowering medicine;

  • heart or blood pressure medicine;

  • medicine to prevent organ transplant rejection;

  • medicine to prevent or treat nausea and vomiting;

  • medicine to treat a breathing disorder;

  • narcotic medicine;

  • a sedative;

  • seizure medicine;

  • steroid medicine;

  • stomach acid reducers; or

  • Viagra and other erectile dysfunction medicines.

This list is not complete and many other drugs can interact with fosamprenavir. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.

Further information

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

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