Antiretroviral Treatment - AIDS/HIV
Antiretrovirals refer to a group of drugs which together form the main medical treatment designed to combat HIV and AIDS.
HIV is regarded as a retrovirus and these types of drugs can slow down the growth of the virus and prevent people from becoming ill. They are NOT a cure.
Antiretrovirals are also referred to as anti-HIV or HIV antiviral drugs. To be effective they have to be taken in combination every day for the rest of someone’s life and they can be a very powerful foe against HIV.
This is known as combination therapy. Three or more antiretrovirals taken together are termed Highly Active Antiretroviral Therapy (HAART) which is very aggressive – and very successful.
Doctors prefer to give antiretrovirals in combination because it reduces the rate at which one of the drugs can become resistant to the virus - in other words it would be hard for a resistant mutant of one of the drugs to get round all three and render them useless. Also the different drugs have different effects on the virus so as a combined whole are usually far more successful.
Antiretrovirals are usually divided into four groups:
Nucleoside Reverse Transcriptase Inhibitors (NRTI)
These drugs are also known quite aptly as “nukes” and work by blocking the enzymes the virus uses to target new cells. Unfortunately although they make HIV unable to affect more cells they can’t do anything about the cells already infected. The drugs include AZT which was the first ever drug given to attack HIV, as well as Abacavir, Trizivir and Truvada.
Non-nucleoside Reverse Transcriptase Inhibitors (NNRTI)
These work slightly different to the “nukes” in that they join together in a different way to prevent the HIV virus from duplicating. They only have an effect on newly infected cells. Drugs include Nevirapine, Delavirdine and Efavirenz.
These basically block the enzyme protease which is one of the many enzymes that HIV uses to replicate itself. The protease in HIV attacks healthy proteins and viruses, cutting them up and assembling them into a functioning HIV virus. Unlike NRTIs and NNRTIs, these drugs can slow down the reproduction of the virus in cells that have been infected for a long time.
Fusion and Attachment Inhibitors
These are new antiretrovirals which are still at the clinical testing stage. They can prevent HIV from reproducing and attaching to cells by blocking the proteins which allow the virus to do exactly that. Drugs include Enfuvirtide.
Needless to say all these antiretrovirals can have unpleasant side effects, the most common being nausea, sickness, fatigue and diarrhoea. Severe side effects include muscle wasting and pain, anaemia and a low white blood cell count (white blood cells are important in the immune system to fight infection.)