Antiretroviral treatment of HIV or human immunodeficiency virus
Introduction
What is HIV?
HIV HUMAN IMMUNODEFICIENCY HIV is a retrovirus (its genome is RNA) that destroys certain cells of the immune system. When HIV damages the immune system, it is easier to get serious and even die from diseases than normal the body could overcome.
The most common HIV transmission form is through unprotected sexual relations, although there is also parenteral and vertical transmission. This virus can also be transmitted to the baby during pregnancy, childbirth or during the breastfeeding process.
Once the virus has been contracted, it remains in the body for life since there is currently no cure for this type of retrovirus; But there are drugs that show that antiretroviral treatments can decrease the amount of HIV in blood, so much that it may not appear in a test, when this happens, HIV is almost impossible to transmit.
This type of virus has a short half life, and DNA copies have high variability, since there is a high mutation rate caused by the large number of errors in the transcription of said virus. The reason for this is that, the conversion of the DNA is carried out by the inverse transcriptase enzyme and this enzyme does not correct errors, so that it provides a great variability of copies.
Many of the mutations are lower than the original virus, although some are superior to the base virus and can enable the virus to resist antiretroviral treatment.
The best defense against resistance is the maximum virus suppression, since reducing the amount of active copies, the mutation rate is reduced.
What is AIDS?
AIDS is a disease caused by HIV. This virus produces damage to the organism’s immune system, so a person has AIDS when he contracts dangerous infections or has an extremely low number of CD4 cells (they are a type of lymphocyte). T CD4 lymphocytes help coordinate the immune response by stimulating other immunocytes, such as macrophages, T CD8 lymphocytes and B lymphocytes to combat infection.
Not everyone who has HIV has AIDS, but all those who have AIDS have HIV, because AIDS is the most serious phase of HIV infection, over time, it ends up causing death.
What are antiretrovirals?
They are specific antiviral medications that are responsible for treating retrovirus infections. An example of this can be the human immunodeficiency virus (HIV), which is the virus responsible for the acquired immuno syndrome (AIDS).
Antiretroviral treatment not only eliminates HIV infection, but also maintains viral replication, increasing the number of CD4+ lymphocytes and decreasing morbidity and mortality. It also improves the quality of life and prevents HIV transmission by sexual path.
Antiretroviral treatment
Combined therapy
GENERAL
Millions of copies are daily produced by HIV in the agency. This virus can exchange its components so as not to be affected by antiretroviral drugs, creating resistance to these medications. The current therapeutic approach is based on the powerful combination of several anti-vih drugs, in order to minvar this pharmacological resistance, this treatment plan is known as combined therapy name.
Goal
The objective of combined therapy is to maintain a low number of viral copies. For this, different antiretroviral drugs are combined, increasing the number of obstacles to viral mutation. Antiretrovirals If they occur individually, they do not have the ability to suppress HIV infection, so they should be used in combinations. These combinations of antiretrovirals can be of synergism (pharmacological or toxicological interaction in which the combined biological effect of one or more chemical substances is greater than the sum of the effects of each element only) positive or negative, this limits the number of combinations available.
A clear example would be the combination of DDI (didosina) and azt (zidovudina) is of negative synergism, since, when administered together, each drug inhibits the action of the other.
Combined therapy effectiveness
The annual appearance of antiretroviral drugs has shown that combined therapy is the most effective treatment for HIV.
Combinations have been carried out, integrating new drugs that have been previously tested.
Combined therapy can:
- Increase viral suppression
- Prevent medication resistance
- Optimize drug exposure
- Simplify the dose
You can also create unexpected toxicity and pharmacological antagonism for sub -therapy concentrations.
Drug classes
There are currently the following types of medications for the treatment of HIV infections, they are classified according to their mechanism of action. And the transcriptase reverse inhibitors and protease inhibitors can be differentiated.
Transcribed Reverse Inhibitors (IRT)
Transcribed back inhibitors (IRT) are classified into two subgroups: nucleosides and non -nucleosides.
- IRT (nucleotides and nucleosides)
They are blocking drugs of the inverse transcriptase of HIV, a key enzyme for the replication of the virus and for the initial infection of the CD4 cells. The operation mechanism of transcriptase back inhibitors is to introduce nucleotides and nucleosides into the viral DNA replacing the natural construction blocks of the DNA, so that the subsequent replication of HIV is prevented by a process called the end of the chain.
Drugs: Zidovudina, Didanosina, Zalcitabina, Estavudina, Ziagen
- IRT (no nucleosides)
They are blockers of the action of the inverse transcriptase of HIV, decreasing the rhythm of chemical reactions that take place during DNA synthesis.
Drugs: Nevirapina, Delavirdina, Efavirenz
Protease inhibitors (IP)
They attack HIV protease enzyme that breaks virus protein chains that are not able to infect more cells.
Drugs: Saquinavir, Indinavir, Ritonavir, Nelfinavir, Amprenavir
Drugs used in combined therapy
Drugs inhibitors of the transcriptase reverse (IRT)
Transcribed back inhibitors (IRT) are classified into two subgroups: nucleosides and non -nucleosides.
- IRT (nucleotides and nucleosides)
They are drugs that hinder the operation of the inverse transcriptase of HIV, fundamental enzyme for the replication of the virus and for the initial infection of CD4 cells. They respectively introduce nucleotides and nucleosides in the viral DNA to replace the natural construction blocks of the DNA, preventing the subsequent replication of HIV through a process that is known as the end of the chain.
Drugs: Zidovudina, Didanosina, Zalcitabina, Estavudina, Ziagen
Zidovudina
Zidovudina, also known as suzidopathyidine or AZT was the first antiretroviral medicine (ARV).
It is an inhibitor of the inverse transcriptase enzyme of the nucleoside analogous type and is considered the basic axis of antiretroviral therapy. This type of inhibited what you do is block the reverse transcriptase (an enzyme produced by HIV and that retrovirus uses to make the transcription of RNA to DNA), produced by HIV and that the retrovirus uses to make the transcription of RNA to DNA), when making this blockade, retrovirus multiplication is prevented.
Zidovudine triffosphate (TZDV) is incorporated into the viral DNA by competitive blocking of the purified transcriptase of HIV, but this drug, it needs to be phosphorylated to be active against this enzyme. The TZDV competitively inhibits DNA VHB polymerase in a way similar to the inhibition of transcriptase back. The protective effect of zidovudine against HIV -induced cytopathogenicity can be blocked in relation to the dose by thymidine, although thymidin has no cytotoxic effect inherent in HIV -infected cells.
Didanisine
It is a synthetic analogous nucleoside. This drug, inside the cell, is converted by cellular enzymes, to Dideoxaxiadenosine 5 ′ -Tiffosphate (DDATP). The DDATP inhibits the activity of the transcriptase reverse of HIV both in competition with the natural substrate, as for its incorporation into the viral DNA interrupting the growth of retroviral DNA.
- IRT (no nucleosides)
They are blocking drugs of the action of the reverse transcriptase of HIV, decreasing the rhythm of key chemical reactions that occur during DNA synthesis.
Drugs: Nevirapina, Delavirdina, Efavirenz
Efavirenz
This is an Irtnns that shows good inhibitory activity against HIV-1.
The reduction of susceptibility to Efavirenz has been reported in HIV-1 variants that contain simple and multiple mutations of the back-transcriptase enzyme. Some studies have recently demonstrated that the resistance profile of Efavirenz overlaps with that of the Irtnns Nevirapina and Delavirdina.
Drugs protease inhibitors (IP)
Saquinavir
The Saquinavir is part of a class of medications known as protease inhibitors. The functioning of this drug is to reduce the amount of HIV in the blood. Although the Saquinavir does not cure HIV, it can reduce the possibility of developing acquired immunodeficiency syndrome (AIDS) and HIV -related diseases, such as serious infections or cancer.
Indinavir
The mechanism of action of this protease inhibitor is by union of the drug to the active protease site and inhibits the activity of the enzyme. This makes the formation of viral particles inhibited. Ritonavir
It is an IP with an HIV-1 resistance profile similar to that of the Indinavir, but different from the Saquinavir. This drug inhibits HIV ASPARTIC PROTEAS. This enzyme is essential for the processing of products of GAG and GAG-POL genes (viral protein precursor genes) in the functioning of viral enzymes and HIV proteins cutting. Inhibition results in the release of non -infectious viral particles immature.
conclusion
Recent advances achieved with combined therapy offer new hopes to HIV+. The treatment based on 3 drugs has produced improvements in the clinical field, more survival time and increased the quality of life of many people. As for the toilets, antiretroviral therapy has facilitated the care of HIV patients+.
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