Treatments Available For HIV And AIDS.

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 infections that resulted. Over the past 10 years, however, therapies have been developed to fight both HIV infection and its associated infections and cancers.

Although there is no treatment currently available that can cure people of HIV or AIDS, a number of therapies have been developed to help them stay healthier and live longer.

• Some medications target HIV itself, to reduce the virus's assault on the immune system, or to even prevent the virus from entering human immune cells.
• Other treatments are used to treat or prevent specific opportunistic infections that threaten the health of people with HIV-damaged immune systems.

Treatments That Suppress HIV

Drugs that interfere with the activity of a retrovirus such as HIV are generally known as antiretrovirals. Nearly all antiretroviral medications currently approved to treat HIV infection target two viral enzymes used by the virus to replicate itself. These enzymes, reverse transcriptase and protease, are involved in different stages of viral replication. A new treatment approved in the past year works in a completely new way by preventing the virus from entering the human immune cells.

Four classes of antiretroviral drugs have been developed to interfere with the activity of these viral enzymes and slow down the multiplication of the virus. These are:

• Nucleoside analog reverse transcriptase inhibitors (NRTIs). NRTIs interrupt an early stage of HIV replication by interfering with the activity of reverse transcriptase. AZT (zidovudine), the first drug approved for treating HIV infection, is an NRTI, as are zalcitabine (ddC), didanosine (ddI), stavudine (d4T), lamivudine (3TC), and abacavir.
• Non-nucleoside reverse transcriptase inhibitors (NNRTIs). NNRTIs also work by hindering the action of reverse transcriptase. This class of drugs includes delavirdine, nevirapine, and efavirenz.
• Protease inhibitors. Protease inhibitors interrupt a later stage of viral replication. This class of drugs includes saquinavir, indinavir, ritonavir, nelfinavir, and amprenavir.
• Fusion inhibitors. Fusion inhibitors prevent HIV from entering human immune cells. The only fusion inhibitor approved to date is enfuvirtide.

Studies have found that various combinations of antiretroviral drugs are more effective in suppressing HIV than antiretroviral drugs used alone. Experts refer to one common treatment approach, usually involving a protease inhibitor combined with two other antiretroviral drugs, as "highly active antiretroviral therapy" or HAART.

Drug combinations, or drug "cocktails," also can help reduce the risk that drug-resistant HIV will develop. When drug resistance occurs, medications that initially succeeded in suppressing the replication of HIV in the patient's body loose their effectiveness. Enfuvirtide works in a unique way that reduces the likelihood of cross-resistance with other HIV drugs.

Antiretroviral drugs have side effects that can limit their use in some people.

• AZT, for example, may result in a loss of blood cells.
• Protease inhibitors can cause nausea, diarrhea, and other symptoms.

Treating AIDS-Related Conditions

Other drugs and therapies are used to prevent or treat opportunistic infections and other AIDS-related conditions:

• Pneumocystis carinii pneumonia. People who develop this lung infection are generally treated with TMP/SMX (a combination of antibiotic drugs) or pentamidine. Doctors also prescribe these medications as preventive therapy for adult patients whose CD4+ T cell counts fall below 200.
• Yeast infections in women. Physicians often prescribe a drug called fluconazole to treat yeast and other fungal infections. Fluconazole also can safely prevent vaginal and esophageal candidiasis without development of drug resistance.
• Severe skin ulcers caused by herpes simplex virus infection. Skin ulcers sometimes respond to an antiviral medication, acyclovir.
• Pelvic inflammatory disease. PID is treated with antibiotics. Women with mild cases may be treated on an outpatient basis. HIV-positive pregnant women suspected of having PID are usually hospitalized, treated with intravenous antibiotics approved for use during pregnancy, and monitored closely.
• HIV-related wasting.Megestrol acetate (Megace) is often prescribed for HIV-associated wasting, but it can cause significant irregular vaginal bleeding in women. Another drug, nandrolone, may not have these side effects and is currently undergoing drug trials.
• Kaposi's sarcoma and other cancers. Cancers are treated with radiation, chemotherapy, or injections of alpha interferon, a genetically engineered, naturally occurring protein.
• CMV Retinitis. Improvements in anti-HIV treatments as well as preventive and therapeutic approaches to managing CMV have resulted in a decreased incidence of CMV retinitis. Today, the incidence of CMV retinitis is about one quarter what it was previous to the introduction of HAART. While early CMV retinitis therapies were delivered intravenously, current treatments include medications in pill form for all stages of CMV retinitis.

What Are Some Of The Problems With AIDS Drug Therapy?

AIDS drugs do not cure the condition, but they help to manage it and postpone life-threatening complications. However, there are problems with AIDS drug therapy:

• Side effects of drugs are a major concern in treatment.
• Another major problem is the cost of the drugs used in treating AIDS. AIDS patients in the United States depend on insurance and government grants to obtain them. The high price of these drugs makes it difficult for third-world countries, which have major AIDS epidemics, to afford to distribute them.

Since antiviral drugs have so far not been curative, the hope is to find a vaccine. The technology for vaccine development is present, and serious efforts are being made to find one.