Antiretroviral therapy
Introduction
Antiretroviral therapy (ART) refers to the use of a combination of antiretroviral (ARV) drugs to suppress the HIV virus and stop the progression of the disease. ART also prevents onward transmission of HIV. It is a critical component of the global response to HIV/AIDS.
History and Development
The development of antiretroviral therapy has been a significant milestone in the history of HIV/AIDS. The first ARV drug, Zidovudine (AZT), was approved by the FDA in 1987. The introduction of combination ART in 1996, often referred to as Highly Active Antiretroviral Therapy (HAART), marked a turning point in the history of the epidemic.
Mechanism of Action
Antiretroviral drugs work by interfering with the replication of the HIV virus. They target different stages of the HIV lifecycle, including entry into the host cell, reverse transcription, integration into the host genome, transcription, and assembly and release of new virus particles.
Classes of Antiretroviral Drugs
There are several classes of antiretroviral drugs, each targeting a different stage of the HIV lifecycle. These include Nucleoside Reverse Transcriptase Inhibitors (NRTIs), Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs), Protease Inhibitors (PIs), Integrase Inhibitors (INIs), and Entry Inhibitors.
Treatment Regimens
The goal of antiretroviral therapy is to achieve and maintain viral suppression. This is typically achieved by a combination of three or more antiretroviral drugs from at least two different classes. The choice of regimen depends on a variety of factors, including the individual's health status, potential drug interactions, potential side effects, and the likelihood of adherence to the regimen.
Adherence to Therapy
Adherence to antiretroviral therapy is critical for achieving and maintaining viral suppression. Poor adherence can lead to drug resistance and treatment failure. Strategies to improve adherence include patient education, medication reminders, and the use of fixed-dose combination pills.
Side Effects and Toxicities
Antiretroviral drugs can have side effects and toxicities, which can affect adherence to therapy. Common side effects include nausea, diarrhea, and rash. More serious toxicities can include liver damage, bone marrow suppression, and metabolic abnormalities.
Drug Resistance
Drug resistance is a major challenge in the treatment of HIV. Resistance can occur when the virus mutates and becomes resistant to the effects of antiretroviral drugs. Resistance testing is recommended before starting therapy and in cases of treatment failure.
Future Directions
Research is ongoing to develop new antiretroviral drugs and treatment strategies. This includes the development of long-acting injectable formulations, the use of gene therapy to make cells resistant to HIV, and the search for a functional cure for HIV.