Treatment
When
AIDS first surfaced in the United States, no drugs were available to combat the
underlying immune deficiency and few treatments existed for the opportunistic
diseases that resulted. Over the past 10 years, however, therapies have been
developed to fight both HIV infection and its associated infections and cancers.
The
Food and Drug Administration has approved a number of drugs for the treatment of
HIV infection. The first group of drugs used to treat HIV infection, called
nucleoside analog reverse transcriptase inhibitors (NRTIs), interrupt an early
stage of virus replication. Included in this class of drugs are zidovudine (also
known as AZT), zalcitabine (ddC), didanosine (ddI), stavudine (D4T), lamivudine
(3TC) and abacavir succinate. These drugs may slow the spread of HIV in the body
and delay the onset of opportunistic infections. Importantly, they do not
prevent transmission of HIV to other individuals. Non-nucleoside reverse
transcriptase inhibitors (NNRTIs) such as delavirdine, nevirapine and efavirenz
are also available for use in combination with other antiretroviral drugs.
A
third class of anti-HIV drugs, called protease inhibitors, interrupts virus
replication at a later step in its life cycle. They include ritonavir,
saquinivir, indinavir and nelfinavir. Because HIV can become resistant to each
class of drugs, combination treatment using both is necessary to effectively
suppress the virus.
Currently
available antiretroviral drugs do not cure people of HIV infection or AIDS,
however, and they all have side effects that can be severe. AZT may cause a
depletion of red or white blood cells, especially when taken in the later stages
of the disease. If the loss of blood cells is severe, treatment with AZT must be
stopped. DdI can cause an inflammation of the pancreas and painful nerve damage.
The
most common side effects associated with protease inhibitors include nausea,
diarrhea and other gastrointestinal symptoms. In addition, protease inhibitors
can interact with other drugs resulting in serious side effects. Investigators
also recently have reported cases of abnormal redistribution of body fat among
some individuals receiving protease inhibitors.
A
number of drugs are available to help treat opportunistic infections to which
people with HIV are especially prone. These drugs include foscarnet and
ganciclovir, used to treat cytomegalovirus eye infections, fluconazole to treat
yeast and other fungal infections, and TMP/SMX or pentamidine to treat Pneumocystis
carinii pneumonia (PCP).
In
addition to antiretroviral therapy, adults with HIV whose CD4+ T-cell counts
drop below 200 are given treatment to prevent the occurrence of PCP, which is
one of the most common and deadly opportunistic infections associated with HIV.
Children are given PCP preventive therapy when their CD4+ T-cell counts drop to
levels considered below normal for their age group. Regardless of their CD4+
T-cell counts, HIV-infected children and adults who have survived an episode of
PCP are given drugs for the rest of their lives to prevent a recurrence of the
pneumonia.
HIV-infected
individuals who develop Kaposi's sarcoma or other cancers are treated with
radiation, chemotherapy or injections of alpha interferon, a genetically
engineered naturally occurring protein.
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Sex
