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fosamprenavir

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

What is fosamprenavir?

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

Fosamprenavir is used to treat HIV, which causes acquired immunodeficiency syndrome (AIDS). Fosamprenavir is for use in adults and children who are at least 4 weeks old. This medicine is not a cure for HIV or AIDS.

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

What is the most important information I should know about fosamprenavir?

Some medicines can cause unwanted or dangerous effects when used with fosamprenavir. Tell each of your healthcare providers about all medicines you use now, and any medicine you start or stop using.

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What should I discuss with my healthcare provider before taking fosamprenavir?

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

There are certain medicines that can cause life-threatening drug interactions with fosamprenavir, 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 fosamprenavir 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 fosamprenavir 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.

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. Do not take this medicine in larger or smaller amounts or for longer than recommended.

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) 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. Fosamprenavir doses are based on weight in children, and any changes may affect your child's dose.

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

Use fosamprenavir 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 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 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 fosamprenavir?

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.

Fosamprenavir side effects

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

Stop taking fosamprenavir 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.

Fosamprenavir 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 fosamprenavir. 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 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.

See also: Side effects (in more detail)

Fosamprenavir dosing information

Usual Adult Dose for HIV Infection:

Therapy-naive patients:
Administered without ritonavir: 1400 mg orally twice a day
Administered in combination with ritonavir: Fosamprenavir 1400 mg plus ritonavir 200 mg orally once a day
or
Fosamprenavir 1400 mg plus ritonavir 100 mg orally once a day
or
Fosamprenavir 700 mg plus ritonavir 100 mg orally twice a day

Protease inhibitor (PI)-experienced patients: Fosamprenavir 700 mg plus ritonavir 100 mg orally twice a day

Usual Adult Dose for Nonoccupational Exposure:

(Not approved by FDA)

Centers for Disease Control and Prevention recommendations: 1400 mg orally twice a day

Duration: 28 days

Prophylaxis should be initiated as soon as possible, within 72 hours of exposure. The alternative regimens recommended for nonoccupational postexposure HIV prophylaxis include fosamprenavir as part of PI-based regimens.

Usual Pediatric Dose for HIV Infection:

Administered without ritonavir:
PI-naive patients who are 2 years of age or older:
Oral suspension: 30 mg/kg (up to 1400 mg/dose) orally twice a day

Tablets:
47 kg or more: 1400 mg orally twice a day

Administered in combination with ritonavir:
PI-naive patients who are at least 4 weeks of age (including infants at a postnatal age of at least 28 days who were born at 38 weeks gestation or greater):
Oral suspension:
Less than 11 kg: Fosamprenavir 45 mg/kg plus ritonavir 7 mg/kg orally twice a day
11 to less than 15 kg: Fosamprenavir 30 mg/kg plus ritonavir 3 mg/kg orally twice a day
15 to less than 20 kg: Fosamprenavir 23 mg/kg plus ritonavir 3 mg/kg orally twice a day
20 kg or more: Fosamprenavir 18 mg/kg (up to 700 mg/dose) plus ritonavir 3 mg/kg (up to 100 mg/dose) orally twice a day

Tablets:
39 kg or more: Fosamprenavir 700 mg plus ritonavir 100 mg orally twice a day

PI-experienced patients who are at least 6 months of age:
Oral suspension:
Less than 11 kg: Fosamprenavir 45 mg/kg plus ritonavir 7 mg/kg orally twice a day
11 to less than 15 kg: Fosamprenavir 30 mg/kg plus ritonavir 3 mg/kg orally twice a day
15 to less than 20 kg: Fosamprenavir 23 mg/kg plus ritonavir 3 mg/kg orally twice a day
20 kg or more: Fosamprenavir 18 mg/kg (up to 700 mg/dose) plus ritonavir 3 mg/kg (up to 100 mg/dose) orally twice a day

Tablets:
39 kg or more: Fosamprenavir 700 mg plus ritonavir 100 mg orally twice a day

Ritonavir capsules may be used for patients weighing at least 33 kg.

What other drugs will affect fosamprenavir?

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.

Where can I get more information?

  • Your pharmacist can provide more information about fosamprenavir.
  • 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.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 10.01. Revision Date: 2015-06-25, 3:20:00 PM.

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