Treating HIV (human immunodeficiency virus), the virus that causes AIDS, is one of most rapidly evolving fields in medicine. New therapies, different combinations of drugs and improved methods for monitoring infection make treatment increasingly complex. There are three important facts about treatment for HIV:

• It is available even for many HIV-infected persons who don't have symptoms yet.

• It can delay progression to AIDS and prolong life.

• It changes all the time, making it critical to remain current with the latest findings.

That's why it's so important that you find an HIV specialist to care for you. Given the speed with which the field changes, many general practice physicians cannot keep up with the latest treatment advances. Being HIV-positive, you may also face unique psychological and social challenges, such as whom to notify, how to handle your feelings, when to start treatment and where to find financial assistance. These are issues that AIDS specialists are familiar with.

An AIDS specialist, typically an infectious disease doctor, will also know the unique ways in which HIV infection impacts a woman's health. For example, HIV-infected women are more likely to experience certain gynecological disorders than HIV-negative women, and are much more likely to have abnormal Pap smears. Consequently, HIV-positive women should have a Pap test every six months if they have symptoms, a prior abnormal Pap test or signs of human papillomavirus infection (HPV), a sexually transmitted disease that causes genital warts and lesions as well as cervical cancer.

In 1996, with the advent of a class of drugs called protease inhibitors, a new model was introduced for treating HIV infection. You've probably heard how these potent drugs used in different combinations have allowed patients once disabled by AIDS to return to work and remain free from serious symptoms. This model uses a powerful combination of at least three drugs from two or more different classes, called combination therapy, or a "drug cocktail." Prior to these powerful drugs, the primary treatment was zidovudine, known as AZT. Patients usually responded to AZT for a little while, but became sick again once the virus mutated and could survive the drug's effects. These mutations occur with other drugs used to treat HIV, as well.

Drug therapy with protease inhibitors can dampen the initial viral surge that spreads through the body. By keeping the virus in check, the drugs can delay the gradual weakening of the immune system.

Additionally, treatment may reduce the chance that an infected person will transmit the virus; if they're effective, the drugs not only reduce the amount of virus in the blood but in bodily fluids, as well.

Finally, people who start early treatment with powerful drug combinations can delay symptoms of infection longer (possibly indefinitely) than those not receiving treatment.

The long-term impact of these drugs remains unknown, however, and once the drugs are stopped, the virus often returns in full force. Moreover, drug-resistant HIV strains continue to develop. Still, while treatment often means taking many pills a day with potentially significant side effects, protease inhibitors and other treatments have turned HIV from a terminal illness into one that can be managed over many years, much like diabetes or high blood pressure.

A treatment management tool introduced in 1996, the viral load test, can accurately monitor how well your body is responding to treatment. The test measures the amount of HIV in your blood-in medical terms, "plasma HIV RNA" and is quantified as "copies per milliliter." The goal is a viral load below 400 copies per milliliter of blood.

Viral load testing is an invaluable treatment guide today in the same way a CD4+ count (testing for white blood cells called T-lymphocytes) was in the first decade of the epidemic. It provides timely information for deciding not only when you should start treatment but when to switch to different drugs if treatment proves ineffective or resistance is developing. The CD4 test is still an important measure, however, indicating the functioning of the immune system.

The overall goal of treatment is to reduce the amount of virus in the bloodstream to a level so low it cannot be detected by the viral load test. Indeed, having "undetectable" virus has become the benchmark for measuring a successful therapy regimen. An undetectable virus does not, however, mean that you're cured or that the virus is completely out of your body.

When should antiretroviral treatment be initiated for an HIV-infected patient? Treatment guidelines from the U.S. Department of Health and Human Services note that any decision regarding beginning or changing antiretroviral therapy (also known as HAART—highly active antiretroviral therapy) should be guided by the results of laboratory tests as well as the individual patient's systematic disease. In general, treatment is recommended when CD4 levels are less than 350 cu. mm or plasma HIV RNA levels are more than 55,000 copies/ml.

Another benefit from HIV treatment is its potential to prevent the serious opportunistic infections that make AIDS a debilitating condition. Prior to protease inhibitors, many AIDS patients were given antibiotics to ward off PJP (Pneumocystis Jirovecii Pneumonia) and MAC (Mycobacterium Avium Complex). Combination drug therapy has allowed many people to stop taking preventive therapy for these AIDS-defining opportunistic infections, if their CD4 counts increase with HAART.

Research has shown that HIV treatment can dramatically reduce the risk of mother-to-infant transmission. Without preventive therapy, about 25 percent of all HIV-positive pregnant women in developed countries pass the virus on to their babies. When women and their infants receive the antiretroviral drug AZT during pregnancy and delivery, however, the risk of transmission drops to below two percent. Today, less than five percent of pregnant women treated with highly effective combinations of multiple anti-HIV drugs pass the virus to their newborns.

With the availability of an effective means of preventing perinatal infection, health care provider are urged to screen all pregnant women for HIV, regardless of individual risk factors. The CDC also recommends postnatal screening for infants not tested before they're born.

Today, 26 drugs are approved for HIV therapy. They fall into four major classes:

• Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) which prevent healthy T-cells from being infected with HIV. These drugs interfere with an enzyme that enables the virus to replicate. NRTIs include:

  • abacavir (Ziagen)

  • abacavir and lamivudine (Epzicom) (abbreviation: ABC+3TC)

  • abacavir, zidovudine and lamivudine (Trizivir) (abbreviation: ABC+AZT+3TC)

  • didanosine (Videx) (abbreviation: ddI)

  • emtricitabine (Emtriva) (abbreviation: FTC)

  • lamivudine (Epivir)

  • stavudine (Zerit) (abbreviation: d4T)

  • tenofovir disoproxil and emtricitabine (Truvada) (abbreviation: TDF+FTC)

  • tenofovir disoproxil fumarate (Viread) (abbreviation: TDF)

  • zalcitabine (Hivid) (abbreviation: ddC)

  • zidovudine and lamivudine (Combivir) (abbreviation: AZT+3TC)

  • zidovudine (Retrovir) (abbreviation: AZT)

• Non-nucleoside reverse transcriptase inhibitors (NNRTIs), which bind to the enzyme reverse transcriptase to prevent the virus from copying itself. They include:

• delavirdine (Rescriptor)

• efavirenz (Sustiva, Stocrin)

• nevirapine (Viramune)

• Protease inhibitors, which prevent the HIV virus from copying itself after entering a cell. They include:

• amprenavir (Agenerase)

• atazanavir (Reyataz)

• darunavir (Prezista)

• fosamprenavir (Lexiva)

• indinavir (Crixivan)

• darunavir (Prezista)

• nelfinavir (Viracept)

• ritonavir (Norvir)

• saquinavir (Invirase and Fortovase)

• tipranavir (Aptivus)

• Fusion inhibitors block the virus' ability to infect certain components of the immune system. So far, just one fusion inhibitor has been FDA approved—enfuviritide (Fuzeon)—but more are on the way.

All AIDS medications carry the potential for toxicity, known as adverse drug reactions. For example, protease inhibitors can redistribute fat cells in some patients. This condition, called lipodystrophy, causes paunches or humps to form in the abdomen or back. Some side effects are life threatening, such as the hypersensitivity reaction associated with Ziagen and the inflammation of the pancreas that can occur with stavudine and didanosine. More common side effects from antiviral drugs are headache, fever, rash and nausea.

You must also watch out for the risk of adverse drug interactions, both with anti-HIV drugs and other pharmaceutical and recreational drugs. An interaction can occur when two anti-HIV drugs have similar side effects. For instance, both zalcitabine and didanosine may cause tingling or pain in the hands, feet and legs, so they shouldn't be prescribed together.

Interactions between anti-HIV drugs and other drugs can make anti-HIV drugs less effective and cause undesirable reactions. The tuberculosis treatment rifabutin, for example, should not be used with the protease inhibitor saquinavir for this reason. This is one more reason you should receive treatment from a provider experienced in HIV care and make sure you tell your health care professional about any medication-prescription or over-the-counter-you're taking, including alternative medicines, supplements, vitamins and minerals.