disoproxil fumarate) is a prescription medication approved as a treatment for the following conditions:
- HIV and AIDS (when used in combination with other HIV medications)
- Chronic hepatitis B infection.
Viread is made by Gilead Sciences, Inc.
Viread is currently the only medication in a class of HIV medications known as nucleotide reverse transcriptase inhibitors (NtRTIs). It is similar to medications in another class, nucleoside reverse transcriptase inhibitors (NRTIs). Viread works by blocking a process that the HIV virus needs in order to multiply.
HIV (human immunodeficiency virus) is the virus that causes AIDS. Like other viruses, it must use a person's own cells to reproduce. However, HIV is a little different from other viruses because it must first convert its genetic material from RNA to DNA. It is the DNA that allows HIV to multiply.
HIV converts its genetic material by using a special protein called the reverse transcriptase enzyme. To create DNA, this enzyme uses several different molecular building-blocks.
Viread works by tricking reverse transcriptase into thinking it is one of these molecular building-blocks. However, it is just different enough that when used to create DNA, Viread actually stops the DNA from being made. Without DNA, HIV cannot multiply.
The medication is not a cure for HIV or AIDS, however. It can help stop HIV from infecting healthy cells in the body, but it does not help cells that have already been infected with the virus.
Viread works similarly for treating chronic hepatitis B, except instead of inhibiting reverse transcriptase, it inhibits an enzyme known as HBV polymerase (a similar enzyme that helps to build DNA).