Lexiva – brand name

Telzir – brand name used in some countries outside the US

Fosamprenavir calcium – generic name

Lexiva belongs to a class of HIV drugs called protease inhibitors (PIs).

Lexiva is an improved version of an older protease inhibitor called Agenerase (amprenavir). Lexiva is the only version now available.

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 Lexiva for use in combination with other HIV drugs for the treatment of HIV infection in adults. Lexiva is also approved for use in children two years of age and older.

Lexiva can be used by people who are just starting treatment and have never taken HIV drugs. It can also be used by people who have been on treatment before and have HIV that is resistant to other HIV drugs.

Lexiva comes in 700 milligram (mg) tablets. A liquid version (50 mg/mL oral suspension) is available for children.

Lexiva can be combined with a small booster dose of the PI Norvir (ritonavir) to make Lexiva work better.

The recommended doses of Lexiva are as follows:

• People who are taking HIV drugs for the first time
  • Two 700 mg Lexiva tablets twice daily (without Norvir)
  • Two 700 mg Lexiva tablets plus one or two 100 mg Norvir capsules once daily
  • One 700 mg Lexiva tablet plus one 100 mg Norvir capsule twice daily
• People who have taken protease inhibitors before:
  • One 700 mg Lexiva tablet plus one 100 mg Norvir capsule twice daily
    

Lexiva can be used to treat children. There are specific dosing instructions that you should discuss carefully with your health care provider.

Lexiva must be used with other medications to treat HIV.

Lexiva can be taken with or without food.

Tell your health care provider if you have liver or kidney problems, hemophilia, or diabetes before taking this medication.

Lexiva should be used with caution in people who are allergic to sulfa drugs.

If you miss a dose of Lexiva by more than four hours, wait and take the next dose at the regular time. If you miss a dose by fewer than four hours, take your missed dose right away. Then take your next dose at the regular time.

As with all HIV drugs, it is important to take Lexiva as prescribed by your health care provider. Missing or skipping doses can cause your blood levels of Lexiva to fall too low and the virus can become resistant to it. This may cause Lexiva and other HIV drugs you are taking to stop working.

Lexiva (with or without Norvir) may be used for people being treated for the first time.

Lexiva combined with Norvir 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.

Lexiva is very similar to Agenerase and will likely not be effective in people who are resistant to Agenerase.

You and your health care provider should use resistance testing and your treatment history to help guide the use of Lexiva and to determine which drugs will work best for you.

If your virus develops resistance to Lexiva 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. This can lead to the drugs not working as well or an increased risk of side effects.

Lexiva can interact with other medications. Taking Lexiva with certain drugs can change the amount of each drug in your blood. Your health care provider may need to either adjust the doses of your drugs to avoid under- or overdosing or change the drugs you currently take.

Lexiva should not be taken with:

• HIV drugs: Agenerase (amprenavir); Kaletra (lopinavir/ritonavir); Rescriptor (delavirdine)
• Acid reflux/heartburn medication: Propulsid (cisapride)
• Antibiotic: Rifadin (rifampin)
• Antimigraine medications (ergot derivatives): Methergine, Methylergometrine (methylergonovine); Ergostat, Cafergot, Ercaf, Wigraine (ergotamine); Ergotrate, Methergine (ergonovine); or D.H.E. 45, Migranal (dihydroergotamine)
• Antipsychotic: Orap (pimozide)
• Sedatives : Versed (midazolam) and Halcion (triazolam)
• Cholesterol-lowering drugs (statins): Zocor (simvastatin) and Mevacor (lovastatin)
• The herb St. John’s wort
• Pulmonary arterial hypertension treatment: Revatio (sildenafil)
• Prostate medication: Uroxatral (alfuzosin)
• Inhaled medications: Serevent, Advair (salmeterol)

If you are taking Lexiva with Norvir, you should also avoid:

• Heart medications: Tambocor (flecainide), Rythmol (propafenone)

If you are taking any of the following medications with Lexiva, speak to your health care provider as your doses may need to be adjusted:

• Antidepressant drugs: Paxil (paroxetine), Desyrel (trazadone)
• Heart medications: Cordarone (amiodarone), Quinaglute/Quinidex (quinidine), lidocaine (systemic)
• Erectile dysfunction drugs: Viagra (sildenafil), Levitra (vardenafil), Cialis (tadalafil)
• Some drugs to treat TB, MAC and other bacterial or fungal infections
• Anticonvulsants: Tegretol (carbamazepine), Luminal (phenobarbital), Dilantin (phenytoin)
• Pulmonary arterial hypertension drugs: Tracleer (bosentan), Adcirca (tadalafil)
• Methadone

Some birth control pills may not work if you are taking Lexiva, so alternative birth control methods should be used.

The drug colchicine needs dose adjustments when taken with Lexiva. Colchicine should not be used at all with Lexiva if you have kidney or liver problems.

This is not a complete list of medications. Because there are many possible drug interactions with Lexiva, it is very important to go over all your medications with your health care provider. Be sure your health care provider 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 among the specific drugs you are taking, see The Well Project info sheet on drug interactions or go to:

http://www.hiv-druginteractions.org/
or
http://hivinsite.ucsf.edu/insite?page=ar-00-02

Most people find Lexiva 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 Lexiva, 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.

• Diarrhea
• Nausea
• Vomiting
• Abdominal pain
• Appetite loss
• Intestinal gas (flatulence)
• Headaches
• Skin rash

More serious side effects:

• Heart attacks and increases in cholesterol: Triglyceride and cholesterol levels should be checked before starting Lexiva and regularly during treatment. It may be necessary for your health care provider to treat high cholesterol and triglycerides with other medications.
• Kidney stones: Tell your health care provider if you have pain in your side, blood in your urine, or pain when you urinate.
• High blood sugar (hyperglycemia), diabetes, or worsening of diabetes may occur.
• Increased bleeding problems in some HIV+ people with hemophilia.
• In rare cases Lexiva can cause a life-threatening hypersensitivity reaction (Stevens-Johnson syndrome). Symptoms may include a severe rash, blisters, mouth sores, swelling, fever, and weakness. Swelling of the face, lips, and tongue (angioedema) has also been reported. Tell your health care provider if you get a rash or develop facial swelling after starting Lexiva.
• Liver problems: This may be indicated by higher liver enzymes or yellowing of the skin or eyes (jaundice). People who already have liver problems, including hepatitis B or C, may find their liver problems get worse.
• 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. For more information on lipodystrophy, see our info sheet.
• Hypersensitivity reaction: Lexiva 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 Lexiva.

If you are experiencing persistent, unusual, or serious side effects, call your doctor right away.

Lexiva is a newer protease inhibitor, and has not been studied in as many people as the older HIV drugs. Studies of Lexiva pharmacokinetics (how the drug is processed by the body) show that the drug behaves similarly in the bodies of women and men.

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.

• The NEAT study (APV30001) included 249 participants starting HIV treatment for the first time, 31 percent (or about 77) of whom were women. After 48 weeks, Lexiva plus Ziagen (abacavir) and Epivir (lamivudine or 3TC ) was about as effective as Viracept (nelfinavir) plus Ziagen and Epivir overall, but Lexiva worked better in people with high viral loads.
  
• In the SOLO study (APV30002), Lexiva boosted with Norvir worked about as well as Viracept when taken with Ziagen plus Epivir. This study, also in people starting HIV treatment for the first time, included 27 percent women, or about 175 women out of 649 total participants.
  
• In the CONTEXT study (APV30003), twice-daily Lexiva boosted with Norvir worked about as well as Kaletra (lopinavir/ritonavir) in people who had stopped responding to treatment with other PIs. This study included 15 percent women, or about 47 women out of 315 total participants.

Studies have shown that HIV+ 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 Lexiva during pregnancy.

An Antiretroviral Pregnancy Registry has been established to collect information on pregnant women who take HIV drugs, including Lexiva. If you are pregnant and taking Lexiva or other HIV drugs, your health care provider can register you by calling 1-800-258-4263 or going to www.apregistry.com.

It is not known whether Lexiva passes into breast milk. HIV+ women should not breast-feed because their babies could be infected with HIV through the breast milk.

Check with your health care provider 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 health care provider know right away so you can be evaluated and, if necessary, treated.