Protease inhibitor is a class of medications used mainly to treat human immunodeficiency virus (HIV). HIV is the virus that causes AIDS. Protease inhibitors are part of a larger group of medications called antiretroviral drugs. These drugs target disease-causing viruses called retroviruses. The United States Food and Drug Administration approved the first protease inhibitor, called saquinavir, in 1995. Since then, drug manufacturers have developed several other protease inhibitors to treat AIDS and other diseases, such as hepatitis C.
HIV infects and kills cells of the immune system called CD4 cells and T lymphocytes. Eventually, the breakdown of the immune system leads to death (see AIDS (How HIV affects the body) ). Protease inhibitors work by blocking the action of an enzyme called protease inside these cells. Enzymes are substances that speed up chemical reactions in living organisms. Without protease, HIV cannot reproduce and infect other cells.
Protease inhibitors are often used in combination with other antiretroviral drugs to treat HIV. This combination is highly effective in decreasing HIV levels and raising the number of CD4 and T lymphocyte cells. The drugs thus improve health and prolong life. However, the drugs have various side effects. These include increased levels of cholesterol and glucose (sugar) in the blood, nausea, vomiting, diarrhea, kidney stones, and liver problems.
