At present there is no cure for HIV/AIDS. However, strides have been made in developing therapies that suppress or manage the replication of the virus and prevent and treat opportunistic infections and diseases. Combined these medical advances have allowed those with access to care to remain relatively healthy for a longer period of time.
Antiretroviral therapy HIV cannot be stopped in the body but it can be suppressed with the use of antiretroviral drugs. These drugs suppress HIV by targeting some of the retrovirus enzymes that allow it to replicate. The specific enzymes - reverse transcriptase and protease - are present in different stages of the viral replication process.
One strategy or therapy to control HIV is the combination of antiretroviral drugs referred to as, highly active antiretroviral therapy (HAART). The objective of this aggressive therapy is to inhibit the growth and replication of HIV by reducing the amount of viral load to levels that are very low or non-detectable. The scientific reasoning behind HAART is to prevent the virus from making resistant mutations. By combining three or more drugs, the virus has to make three or more simultaneous mutations which is much less likely than making resistance to just one.
In HAART, a combination of three or more drugs in the following classes is usually prescribed:
Nucleoside-analog Reverse Transcriptase Inhibitors (NRTI) – act against the HIV reverse transcriptase enzyme found early in the replication process
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI) – bind against the HIV reverse transcriptase enzyme
Protease Inhibitors – act against the HIV protease enzyme found later in the replication process
HAART is effective, however there are unfortunately increasing reports of drug-resistance to one or more of the drugs in the therapy.
A new class of drugs, fusion inhibitors/chemochines (which act against HIV’s ability to fuse and enter the host immune cell) are now prescribed if drug resistance is seen.
Limits of Antiretroviral Therapies Antiretroviral therapy does have side effects, the most common of which are nausea and vomiting. However, some patients experience more serious side effects such as changes in their metabolic system and toxicity to the antiretroviral drugs on other cells in the body. These side effects can lead to additional medical complications.
Antiretroviral therapy – particularly HAART – poses significant compliance problems. Treatment regimens require taking many drugs (up to 20) throughout the day and adhering to strict dietary guidelines. Compliance to HAART is difficult to maintain. Due to drug side effects and the psychological strain of adhering to strict guidelines, many patients without medical consultation, decrease their required drug dosage, discriminately discontinue and resume therapy, or stop therapy completely. By not fully complying with HAART, it has been proved that not only will HIV levels rise but that there is a greater likelihood of drug resistance.
Lastly, and perhaps most frustrating for both patient and medical practitioner, is that with time resulting HIV mutations often become resistant to antiretroviral drugs thereby limiting their effectiveness.
