Generic name: Fosamprenavir calciumBrand names: Lexiva
Lexiva is prescribed for adults with human immunodeficiency virus (HIV) infection. HIV undermines the immune system, reducing the body's ability to fight off other infections and eventually leading to the deadly condition known as acquired immune deficiency syndrome (AIDS).
Lexiva slows the progression of HIV by interfering with an important step in the virus's reproductive cycle. The drug is a member of the group of "protease inhibitors." Lexiva is prescribed only as part of a "drug cocktail" that attacks the virus on several fronts. It is not to be used alone.
Lexiva is not a cure for HIV infection or AIDS. It does not completely eliminate HIV from the body, nor does it totally restore the immune system. There is still a danger of developing serious opportunistic infections (that is, infections that develop when the immune system falters). It is important, therefore, to continue seeing your doctor for regular blood counts and tests. Notify your health care provider immediately of any change in your general health.
Combining Lexiva with certain drugs can cause serious—and possibly life-threatening—side effects (see "Possible food and drug interactions when taking Lexiva"). Be sure to tell your doctor and pharmacist what medications you are taking, both prescription and over-the-counter, and let them know when you stop taking any medication.
Lexiva can be taken with or without food. Take Lexiva every day as prescribed. Do not change your dose or stop taking Lexiva without talking to your doctor.
Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor as soon as possible. Only your doctor can determine if it is safe to continue using Lexiva.
If Lexiva causes an allergic reaction, you will not be able to use it. If you have severe liver damage, you should not use Lexiva.
Certain drugs should never be combined with Lexiva due to the risk of serious—and possible life-threatening—side effects (see "Possible food and drug interactions when taking Lexiva").
There is no reason to believe that taking Lexiva lowers your chances of transmitting HIV to others. Continue to take precautions to prevent transmission of virus.
Lexiva can interfere with oral contraceptives. Use a backup form of birth control to avoid an unwanted pregnancy.
Lexiva must be used with caution if you have liver problems. If you have any liver disorder, make sure your doctor is aware of it.
One serious potential side effect of Lexiva is a rash that occasionally becomes so severe as to be life-threatening. If you notice any signs of rash, inform your doctor immediately. If the rash gets worse or is accompanied by fever, blisters, mouth sores, red eyes, swelling, or flu-like symptoms, stop taking the drug and call your doctor.
Lexiva may trigger diabetes or make it worse. If this occurs, you may have to start taking insulin or oral diabetes drugs, or have your dosage of these medications adjusted. Lexiva plus ritonavir can increase levels of a lipid called triglyceride, possibly resulting in the need for treatment.
Like other HIV drugs, Lexiva sometimes causes a redistribution of body fat, resulting in added weight around the waist, a "buffalo hump" of fat on the upper back, breast enlargement, and wasting of the face, arms, and legs. It's not known why this occurs, or what long-term effects it might have.
Lexiva belongs to the sulfonamide family of drugs. If you have an allergy to sulfa drugs such as sulfamethoxazole, be sure to tell your doctor.
Be sure to check with your doctor about the medicines and herbal remedies that should NOT be taken with Lexiva. Due to the danger of life-threatening side effects, Lexiva should never be combined with any of the following:CisaprideDihydroergotamineErgonovineErgotamineLovastatinMethylergonovinePimozideMidazolamSimvastatinTriazolam
Due to the potential for serious or life-threatening side effects, your doctor will monitor you closely if you must take Lexiva with any of the following:AmiodaroneAntidepressants known as tricyclics, such as amitriptyline and imipramineCertain cholesterol-lowering drugs in the statin family, such as atorvastatinBepridilLidocaineQuinidine
If you are taking both Lexiva and the HIV drug ritonavir, you must be careful to avoid the heart medications flecainide and propafenone.
Rifampin and St. John's wort should never be given with Lexiva because they combat the antiviral effects of Lexiva. Delavirdine should not be given with Lexiva as the combination may lead to resistance to delavirdine.
Be careful about combining Lexiva with Viagra or other erectile dysfunction drugs such as tadalafil or Levitra. The combination increases the risk of the side effects of those agents, such as low blood pressure, changes in your vision, and persistent painful erection.
If Lexiva is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Lexiva with the following:Acid reflux medications classified as "proton pump inhibitors" such as esomeprazole and rabeprazoleAntifungal medications such as itraconazole and ketoconazoleAntiulcer medications classified as H2-receptor antagonists, such as cimetidine and ranitidineAnxiety medications (tranquilizers) such as alprazolam, clorazepate, and diazepamDexamethasoneEfavirenzFlurazepamHigh blood pressure and angina medications (calcium channel blockers), such as amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nimodipine, nisoldipine, and verapamilHIV medications such as indinavir and nelfinavirImmune-suppressing drugs such as cyclosporine, sirolimus, and tacrolimusLopinavir/ritonavirMethadoneNevirapineOral contraceptivesRifabutinRitonavirSaquinavirSeizure medications such as carbamazepine, phenobarbital, and phenytoinWarfarinYou should not take nevirapine and Lexiva without ritonavir.While taking Lexiva and rifabutin, the dosage of rifabutin should be cut down by half or more.
The effects of Lexiva during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, tell your doctor immediately.
Since HIV infection can be passed to your baby through breast milk, you should not breastfeed.
If you have never taken anti-HIV medication before
Your doctor will prescribe one of the following regimens:
If you have taken anti-HIV medication anytime before
The recommended dose of Lexiva is 700 milligrams twice daily plus ritonavir 100 milligrams twice daily. HIV-infected persons who have taken protease inhibitors before should NOT take Lexiva plus ritonavir once daily.
If you are taking Lexiva and ritonavir with efavirenz
If you are taking this combination once a day, your doctor will increase the usual dose of ritonavir to 300 milligrams. No dosage adjustment is needed if you are taking this combination twice a day.
Lexiva is not recommended for use in children.
THOSE WITH REDUCED LIVER FUNCTION
Your doctor may prescribe Lexiva at a reduced dose of 700 milligrams twice daily if you have mild or moderate liver damage and are not also taking ritonavir. Lexiva is not recommended for people with severe liver damage.
Little is known about the symptoms of Lexiva overdose. However, any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.