by Dr. Terri Creagh
January 2004 (Reviewed and Revised October 2008)
Agenerase – brand name
amprenavir – generic name
Agenerase belongs to a class of HIV drugs called protease inhibitors (PIs). A newer version of Agenerase called Lexiva (fosamprenavir) is available. Because Lexiva is easier to take, it is now preferred to Agenerase.
The PIs block protease, a protein that HIV needs to make more copies of itself. This may slow down HIV disease.
The Food and Drug Administration (FDA) has approved Agenerase for use in combination with other HIV drugs for the treatment of HIV infection in adults and children over four years old.
Agenerase comes in:
- 50 milligram (mg) capsules
Because Lexiva (the newer version of Agenerase) is now preferred, the drug manufacturer has discontinued the 150 mg Agenerase capsules (the 50 mg capsules and liquid are still available).
The standard adult dose of Agenerase can be taken the following ways:
- 600 mg (12 50 mg capsules) of Agenerase plus 100 mg (one 100 mg capsule) of Norvir two times a day
If you are taking Agenerase, speak to your doctor about taking Lexiva instead.
Agenerase liquid should not be used by:
- Infants or children younger than four years old
- Pregnant women
- People with liver or kidney failure
Agenerase is a sulfa drug – tell your doctor if you are allergic to sulfa drugs.
Agenerase can be taken with or without food, but high-fat meals should be avoided.
Agenerase must be used with other HIV medications to treat HIV.
Check with your child’s doctor for children’s dosing.
Speak to your doctor if you have liver or kidney problems, diabetes, or hemophilia.
As with all HIV drugs, it is important to take Agenerase as prescribed. Missing or skipping doses can cause your blood levels of the drug to fall too low and resistance can develop. When your virus becomes resistant to an HIV medication, that drug may stop working.
Agenerase works better when combined (or “boosted”) with Norvir.
Agenerase (combined with Norvir) may be used by people being treated for the first time.
Agenerase may work against HIV that is resistant to some of the other PIs, so it may be a good option for people who need to switch therapies due to PI drug failure.
Your doctor can run a resistance test to help determine whether Agenerase is likely to work for you.
Agenerase crosses the blood-brain barrier (which protects the brain and spinal cord), so it may be able to fight HIV in the brain.
Lexiva (the newer version of Agenerase) is now preferred. If you are taking Agenerase, speak to your doctor about taking Lexiva instead.
If your virus develops resistance to Agenerase then it may stop working or not work as well for you. You also may not get as much benefit from the other PIs.
Sometimes taking more than one medication can cause drug interactions. Taking certain drugs (including some HIV drugs, TB drugs, drugs to treat erectile dysfunction such as Viagra, antifungals, and drugs to lower cholesterol) with Agenerase can change the amount of each drug in your blood. Your doctor may need to adjust the doses of your drugs to avoid under- or overdosing.
Do not take antacids within one hour of a dose of Agenerase.
People taking liquid Agenerase should not drink alcohol or take Antabuse (disulfiram) or Flagyl (metronidazole).
Certain medications (including methadone, birth control pills, certain antibiotics, acid reflux/heartburn drugs, headache drugs, antihistamines, calcium channel blockers, sedatives, and antipsychotic drugs) should not be taken with Agenerase. You should not take vitamin E supplements or St. John’s wort either.
Be sure your doctor knows about all the medications you are taking (including over-the-counter, prescription, street drugs, and herbs), even if you only use them occasionally.
For more information and additional resources to check interactions between the particular drugs you are taking, see our info sheet on drug interactions.
Most people find Agenerase easy to tolerate, but it is possible that unexpected long-term side effects could show up later.
If you do experience any side effects from Agenerase, they are likely to be temporary and go away as your body adjusts to the medication. If you experience any of the side effects listed below, call your doctor for advice. Do not just stop taking your medication.
- Abdominal pain
- Intestinal gas (flatulence)
- Skin rash
- Tingling or numbness around the mouth
More serious side effects:
- In rare cases Agenerase can cause a life-threatening hypersensitivity reaction (Stevens-Johnson syndrome). Symptoms may include a severe rash, blisters, mouth sores, swelling, fever, and weakness.
- Liver toxicity: this may be indicated by elevated liver enzymes or yellowing of the skin or eyes (jaundice).
- Rare hemolytic anemia (destruction of red blood cells)
- Lipodystrophy, which may include elevated blood sugar (glucose), elevated lipid levels ( cholesterol and triglycerides), and fat gain or loss in certain areas. The exact causes of lipodystrophy are not known, but may include HIV and/or HIV drugs. It is unclear if Agenerase will cause or impact symptoms of lipodystrophy. For more information on lipodystrophy, see our info sheet.
- Hypersensitivity reaction: Agenerase contains an ingredient called sulfa, which can cause an allergic reaction in some people. If you are allergic to Bactrim or Septra, you have a sulfa allergy and should use caution with Agenerase.
If you are experiencing persistent, unusual, or serious side effects, call your doctor right away.
Studies of Agenerase pharmacokinetics (how the drug is processed by the body) show that the drug behaves similarly in the bodies of women and men.
The PROAB3001 study showed that Agenerase plus Retrovir (zidovudine or AZT) plus Epivir (lamivudine or 3TC) worked better than Retrovir plus Epivir without Agenerase. This study included 11 percent women, or about 25 women out of 232 total participants.
The PROAB3006 study compared Agenerase to Crixivan (indinavir). This trial included 20 percent women, or about 100 women out of 504 total participants. In this study, Agenerase did not work as well as Crixivan. People taking Agenerase were less likely to have an undetectable HIV viral load and their CD4 cells did not increase as much.
Some studies suggest that the metabolic side effects (lipodystrophy) associated with PIs may be somewhat different in women and men. However, it is still unclear if women are more likely to gain or lose body fat in certain areas than men.
Studies have shown that pregnant women who use HIV drugs can greatly reduce the risk of passing HIV on to their babies. There have been no formal studies on the use of Agenerase during pregnancy; however pregnant women should not use the liquid formulation.
Check with your doctor about the best treatment options for you and your baby if you are thinking of getting pregnant.
Click this link for more information about pregnancy.
People who are starting HIV treatment for the first time may develop Immune Reconstitution Syndrome or IRS (also called Immune Reconstitution Inflammatory Syndrome or IRIS). IRS can happen as a result of the immune system getting stronger and responding to an HIV-related infection such as Mycobacterium avium infection (MAC), cytomegalovirus (CMV), Pneumocystis jirovecii pneumonia (PCP), or tuberculosis (TB). People may have been treated for these infections in the past or not even know they have them. If you notice any unusual symptoms soon after starting HIV drugs for the first time, let your doctor know right away so you can be evaluated and, if necessary, treated.
Eron, J.J, et. al. (2001). A phase II trial of dual protease inhibitor therapy: amprenavir in combination with indinavir, nelfinavir, or saquinavir. Journal of Acquired Immune Deficiency Syndromes, 26(5). 458-61.
Goodgame, J.C, et. al. (2000). Amprenavir in combination with lamivudine and zidovudine versus lamivudine and zidovudine alone in HIV-1-infected antiretroviral-naive adults. Amprenavir PROAB3001 International Study Team. Antiviral Therapy, 5(3). 215-225.
Hammer, S., et. al. (2002). Dual versus single protease inhibitor therapy following antiretroviral therapy following antiretroviral treatment failure: a randomized trial. Journal of the American Medical Association, 288(2). 169-180.
Nadler, J., et. al. (2003). The NEAT Study: GW433908 efficacy and safety in ART-naïve subjects, final 48-week analysis. 10th Conference on Retroviruses and Opportunistic Infections. Boston, MA. Abstract 177.