Fosamprenavir (By mouth)


Fosamprenavir (fos-am-PREN-a-vir)

Treats human immunodeficiency virus (HIV) infection. HIV causes acquired immune deficiency syndrome (AIDS). Fosamprenavir does not cure HIV or AIDS, but it may slow the progress of the disease when used in combination with other drugs.

Brand Name(s)


When This Medicine Should Not Be Used

How to Use This Medicine

Liquid, Tablet

  • Take your medicine as directed.
  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
  • Tablets: These may be taken with or without food.
  • Oral liquid: Children should take the oral liquid with food. Adults should take it without food. Retake if you vomit within 30 minutes of taking the medicine. Shake the oral liquid well before each use. Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
  • Fosamprenavir is used with other medicines to treat HIV infection. Take all other medicines your doctor has prescribed as part of your combination treatment.
  • Contact your doctor or pharmacist ahead of time when your supply of this medicine is running low. Do not allow yourself to run out of this medicine.

If a dose is missed:

  • Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine

  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Oral liquid may be stored in the fridge or at room temperature. Do not freeze.
  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • There are many other drugs that can interact with fosamprenavir. Make sure your doctor knows about all other medicines and supplements you are using.
  • Make sure your doctor knows if you are also using medicine to treat heart rhythm problems (such as amiodarone, bepridil, lidocaine, quinidine, Cardioquin®, Cordarone®), a blood thinner (such as warfarin, Coumadin®, Jantoven®), certain blood pressure medicines (such as amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nimodipine, nisoldipine, verapamil, Cardizem®, Norvasc®), or medicine to lower cholesterol (such as atorvastatin, rosuvastatin, Crestor®, Lipitor®).
  • Tell your doctor if you are also using bosentan (Tracleer®), birth control pills, medicine for seizures (such as carbamazepine, phenobarbital, phenytoin, Dilantin®, Tegretol®), medicine for depression (such as amitriptyline, imipramine, paroxetine, trazodone, Elavil®), medicine for anxiety (such as alprazolam, clorazepate, diazepam, flurazepam, Valium®, Xanax®), medicine to treat an infection (such as itraconazole, ketoconazole, rifabutin, Mycobutin®, Nizoral®), medicine to treat hepatitis C (such as boceprevir, telaprevir, Incivek®, Victrelis®), a steroid medicine (such as dexamethasone, fluticasone, Decadron®, Flonase®), a stomach medicine (such as cimetidine, famotidine, ranitidine, Pepcid®, Tagamet®, Zantac®), medicine to treat gout (such as colchicine, Colcrys®), medicine to treat breathing problems (such as salmeterol, Advair®, Serevent®), medicine that weakens the immune system (such as cyclosporine, rapamycin, tacrolimus, Gengraf®, Neoral®, Prograf®, Rapamune®, Sandimmune®), a narcotic pain reliever (such as methadone, Dolophine®), or medicine to treat erectile dysfunction (such as sildenafil, tadalafil, vardenafil, Cialis®, Levitra®, Viagra®).
  • Make sure your doctor knows if you are using other medicine to treat HIV or AIDS (such as atazanavir, efavirenz, indinavir, lopinavir/ritonavir, maraviroc, nelfinavir, nevirapine, raltegravir, saquinavir, Crixivan®, Isentress®, Kaletra®, Reyataz®, Sustiva®). Do not take this medicine and amprenavir at the same time.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant, or if you have kidney disease, liver disease (especially hepatitis B or C), diabetes, high cholesterol, hemolytic anemia, or hemophilia (a bleeding problem). Your doctor also needs to know if you are allergic to sulfa drugs (sulfonamides) such as Bactrim® or Septra®.
  • Do not breastfeed. You can spread HIV or AIDS to your baby through your breast milk.
  • Serious skin reactions can occur with this medicine. Tell your doctor right away if you have blistering, peeling, or loose skin while using this medicine.
  • Your immune system may get stronger when you start taking HIV medicines. Tell your doctor right away if you notice any changes in your health. Sometimes the immune system will start to fight infections that were hidden in your body, such as pneumonia, herpes, or tuberculosis.
  • Birth control pills may not work while you are using fosamprenavir. Use another form of birth control to avoid getting pregnant. Other forms include condoms, a diaphragm, or contraceptive foam or jelly.
  • This medicine may cause you to have excess body fat. Tell your doctor if you notice changes in your body shape, such as an increased amount of fat in the upper back and neck, or around the chest and stomach area. You might also lose fat from the legs, arms, and face.
  • This medicine may increase blood sugar levels. Tell your doctor if you notice a change in the results of your blood or urine sugar tests, or if you have any questions.
  • This medicine may increase your risk of kidney stones. Tell your doctor right away if you have blood in your urine, pain in your side, or pain when you urinate.
  • This medicine will not keep you from giving HIV to others. Always practice safe sex, even if your partner also has HIV. Do not share needles or other items that may have blood or body fluids on them.
  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Blistering, peeling, or red skin rash
  • Blood in the urine, pain in your side, pain when you urinate
  • Dark-colored urine or pale stools, nausea, vomiting, loss of appetite, pain in your upper stomach, yellow skin or eyes
  • Fever, chills, cough, sore throat, and body aches
  • Increased hunger or thirst, increased urination, unexplained weight loss
  • Unusual bleeding or bruising
  • Unusual tiredness or weakness

If you notice these less serious side effects, talk with your doctor:

  • Headache
  • Mild diarrhea, nausea, vomiting
  • Mild skin rash
  • Weight gain around your neck, upper back, breast, face, or waist

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Version Info

  • Last reviewed on 8/4/2014

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