protease inhibitors

Protease Inhibitors



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.


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.


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.


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.


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.



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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.


National AIDS Treatment Advocacy Project. 580 Broadway, Ste. 403, New York, NY 10012. (888) 266-2827.

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), a class of drugs used in antiretroviral therapy against HIV, which prevent the cleavage of viral proteins.
References in periodicals archive ?
Johnson has been taking protease inhibitors, which reduce illnesses and lengthen life in some patients.
HUDDINGE, Sweden -- Medivir (STO:MVIRB) (Huddinge, Sweden) and one of China's largest pharmaceutical companies, Jiangsu Hengrui Medicine Company (Shanghai), instigated a research collaboration in December 2003 to develop protease inhibitors against chronic obstructive pulmonary disease (COPD).
Tipranavir (brand name Aptivus), a protease inhibitor that usually works against HIV that is resistant to other protease inhibitors, was recommended for approval by the FDA's Antiviral Drugs Advisory Committee at a meeting on May 19, 2005.
Unlike findings from other studies, protease inhibitors did not increase the risk of diabetes in this group of HIV+ women.
The results were described at the 2nd International AIDS Society Conference on HIV Pathogenesis and Treatment in Paris, France in presentations titled "640385, a Broad Spectrum Inhibitor of Wild-Type and Protease Inhibitor-Resistant HIV-1" and "Discovery and Evaluation of 640385, a Third-Generation HIV Protease Inhibitor: Broad Spectrum Inhibition of Wild-Type and Multi-PI-resistant Viruses by Femtomolar HIV Protease Inhibitors.
One day, he was chatting with Diana Roe, a fellow student, about one of the field's latest rages--HIV protease inhibitors designed to combat the AIDS virus--and the discussion turned to unexpected new therapies that might come from medicinal chemists.
Early studies of protease inhibitors as monotherapy demonstrated that resistance could develop quickly.
The Food and Drug Administration has issued an advisory against taking the supplement with protease inhibitors or non-nucleoside reverse transcriptase inhibitors.
AIDS-infected children got their first drugs from the powerful class of protease inhibitors Friday when the government approved two pediatric formulas.
Protease Inhibitors (PIs) are a key component to the current HIV standard of care, the Highly Active Anti-Retroviral Treatment (HAART) consisting of a cocktail of HIV medicines.
So we enrolled 10 people who had virologic suppression on Sustiva (efavirenz), ten others taking Viramune (nevirapine), and 10 taking protease inhibitors, to join our study.
For patients who have never taken protease inhibitors, Lexiva can be taken once or twice a day, depending on the Lexiva dose and whether Norvir (another protease inhibitor) is taken to boost Lexiva.