protease inhibitors

Protease Inhibitors

 

Definition

A protease inhibitor is a type of drug that cripples the enzyme protease. An enzyme is a substance that triggers chemical reactions in the body. The human immunodeficiency virus (HIV) uses protease in the final stages of its reproduction (replication) process.

Purpose

The drug is used to treat selected patients with HIV infection. Blocking protease interferes with HIV reproduction, causing it to make copies of itself that cannot infect new cells. The drug may improve symptoms and suppress the infection but does not cure it.

Precautions

Patients should not discontinue this drug even if symptoms improve without consulting a doctor.
These drugs do not necessarily reduce the risk of transmitting HIV to others through sexual contact, so patients should avoid sexual activities or use condoms.

Description

Protease inhibitors are considered one of the most potent medications for HIV developed so far.
This class of drugs includes indinavir (Crixivan), ritonavir (Norvir), nelfinavir (Viracept), amprenavir (Agenerase), lopinavir plus ritonavir (Kaletra), saquinavir (Fortovase), and a new drug called atazanavir (Reyataz). Reyataz received approval from the U.S. Food and Drug Administration (FDA) in mid-2003 and was the first protease inhibitor approved for once-daily dosing. Several weeks or months of drug therapy may be required before the full benefits are apparent.
The drug should be taken at the same time each day. Some types should be taken with a meal to help the body absorb them. Each of the types of protease inhibitor may have to be taken in a different way. In most cases, protease inhibitors are part of a combination therapy, used in conjunction with other classes of HIV drugs.

Risks

Common side effects include diarrhea, stomach discomfort, nausea, and mouth sores. Less often, patients may experience rash, muscle pain, headache, or weakness. Rarely, there may be confusion, severe skin reaction, or seizures. Some of these drugs can have interactions with other medication, and indinavir can be associated with kidney stones. Diabetes or high blood pressure may become worse when these drugs are taken. Reyatraz has been shown to have fewer side effects than some protease inhibitors, though it can interact with other medications, including certain heart medications and antidepressants.
Experts do not know whether the drugs pass into breast milk, so breastfeeding mothers should avoid them or should stop nursing until the treatment is completed.

Resources

Periodicals

"HIV Drugs Approved as of August 2003." AIDS Treatment News July 25, 2003: 4.
LoBuono, Charlotte. "FDA Gives Bod to First Once-daily Protease Inhibitor." Drug Topics July 21, 2003: 16.
Wilson, Billie Ann. "Understanding Strategies for Treating HIV." Medical Surgical Nursing 6 (April 1, 1997): 109-111.

Organizations

National AIDS Treatment Advocacy Project. 580 Broadway, Ste. 403, New York, NY 10012. (888) 266-2827. http://www.natap.org.

Key terms

Human immunodeficiency virus (HIV) — The virus that causes AIDS.

protease inhibitors

A range of drugs that interfere with the action of the enzyme protease used by HIV to activate the synthesis of its capsid by processing the viral GAG protein. These drugs slow the progression of the infection and lengthen life. An undesirable direct or indirect effect is the abnormal laying-down of body fat and high levels of lipids in the blood, which may lead to coronary artery disease and strokes. Brand names are indinavir, ritonavir and saquinavir.

protease inhibitors (prōˑ·tē·ās in·hi·biˑ·terz),

n.pl a class of drugs used in antiretroviral therapy against HIV, which prevent the cleavage of viral proteins.
References in periodicals archive ?
Protease inhibitors were extracted from the seeds of Lavatera cashmeriana Camb by ammonium sulphate precipitation and purified by chromatography on DEAE-cellulose and Sephadex G-100 column.
People who had tried earlier antiretroviral combinations controlled HIV better with Prezista/Norvir (darunavir/ritonavir) than with Kaletra (lopinavir/ ritonavir) in a large trial comparing these two protease inhibitors.
The group conducted a study, published recently in the New England Journal of Medicine, that investigated the association of cumulative exposure to protease inhibitors and non-nucleoside reverse transcriptase inhibitors with the risk of myocardial infarction.
People have many types of protease inhibitors in their blood, but not the ones that break down certain venoms.
Have Meds, Will Travel Traveling with meds has always been a challenge for HIVers, but things got a bit easier in October when the FDA approved a tablet form of the protease inhibitor Kaletra, making one of the world's most commonly prescribed protease inhibitors travel-ready.
Prezista (also called darunavir, or TMC-114), a new protease inhibitor active against many of the viruses resistant to other protease inhibitors, was approved by the FDA on June 23 "for the treatment of human immunodeficiency virus (HIV) infection in antiretroviral treatment-experienced adult patients, such as those with HIV-1 strains resistant to more than one protease inhibitor.
Starting in 1996, several studies and cohorts demonstrated dramatic decreases in mortality and opportunistic infections with the widespread availability of the protease inhibitors.
Through this partnership with Vertex, a leader in the discovery and development of HCV protease inhibitors, we hope to accelerate the advancement of novel therapeutics for hepatitis C infection, and we are pleased to add VX-950 to our pipeline of innovative drugs in development.
Protease inhibitors can cause more than a 10-fold increase in sildenafil levels, which can lead to unpleasant side effects in patients taking both drugs, fan R.
But investigators are examining all the other protease inhibitors to see if they can be used with this dosing regimen.
TK: Our disbanding also corresponds to the growing efficacy of groups like TAG and the introduction of protease inhibitors.
1) Furthermore, women who take protease inhibitors as part of their combined drug regimen are no more likely to have a premature or very premature delivery or a low-birth-weight infant than are women who use combination therapy without these drugs, monotherapy or no therapy.