What is the mechanism of action of nucleoside reverse transcriptase inhibitors NRTIs in chronic hepatitis B infection?

What is the mechanism of action of nucleoside reverse transcriptase inhibitors NRTIs in chronic hepatitis B infection?

Mode of Action – NRTI Nucleoside Reverse Transcriptase Inhibitors (NRTIs) inhibit reverse transcription by causing chain termination after they have been incorporated into viral DNA. For these drugs to be active they need to be phosphorylated intracellularly.

Which drug is responsible for inhibition of viral reverse transcriptase?

The NRTIs were the first class of ARVs available for the treatment of HIV infection. NRTIs inhibit the HIV reverse transcriptase enzyme, which is responsible for the reverse transcription of viral RNA into DNA.

What does reverse transcriptase inhibitors do?

Nucleoside reverse transcriptase inhibitors (NRTIs) block reverse transcriptase (an HIV enzyme). HIV uses reverse transcriptase to convert its RNA into DNA (reverse transcription). Blocking reverse transcriptase and reverse transcription prevents HIV from replicating.

What are the two different mechanisms of action for antiretrovirals?

Current ARV mechanisms of action: Block reverse transcriptase to disrupt copying of HIV genetic code (NRTIs; NNRTIs) Block protease enzyme, preventing maturation of new virions (PIs) Prevent fusion of HIV with cell membranes (Fusion inhibitors)

What mechanism of action or pharmacological action is best associated with protease inhibitors?

Protease inhibitor drugs block the action of protease enzymes. This prevents protease enzymes from doing their part in allowing HIV to multiply, interrupting the HIV life cycle as a result. This can stop the virus from multiplying.

How can retroviral growth be inhibited?

RNAi could also inhibit the growth of RSV and HIV in cell culture. Analysis of the step of the retroviral life cycle that is inhibited by RNAi revealed that it primarily prevented accumulation of the viral RNAs synthesized late during infection.

What is the process of reverse transcription?

In biology, the process in cells by which an enzyme makes a copy of DNA from RNA. The enzyme that makes the DNA copy is called reverse transcriptase and is found in retroviruses, such as the human immunodeficiency virus (HIV). Reverse transcription can also be carried out in the laboratory.

What viruses use reverse transcriptase?

Reverse transcriptases are used by viruses such as HIV and hepatitis B to replicate their genomes, by retrotransposon mobile genetic elements to proliferate within the host genome, and by eukaryotic cells to extend the telomeres at the ends of their linear chromosomes.

Which of the following is a possible side effect of antiretrovirals?

Other side effects from antiretroviral drugs can include:

• hypersensitivity or allergic reactions, with symptoms such as fever, nausea, and vomiting.
• bleeding.
• bone loss.
• heart disease.
• high blood sugar and diabetes.
• lactic acidosis (high lactic acid levels in the blood)
• kidney, liver, or pancreas damage.

What are the adverse effects of protease inhibitors?

Confirmed potential side effects of protease inhibitors are:

• Insulin resistance.
• Nausea and diarrhea.
• Development of gallstones or kidney stones.
• Changes in how things taste.
• Insomnia.
• Elevated numbers in liver function tests.
• Rash or dry skin.
• Elevated cholesterol.

Are protease inhibitors bad?

Protease inhibitors and statins taken together may raise the blood levels of statins and increase the risk for muscle injury (myopathy). The most serious form of myopathy, called rhabdomyolysis, can damage the kidneys and lead to kidney failure, which can be fatal.

What steps in viral cycle are drug targets?

Main Targets for Antiviral Drugs Specific events in virus replication identified as targets for antiviral agents are viral adsorption, penetration, uncoating, and viral nucleic acid synthesis as well as viral protein synthesis.

What is the mechanism of action of reverse transcriptase inhibitors?

Mechanism of action. Reverse transcriptase inhibitors are active against HIV, a retrovirus. The drugs inhibit RNA virus replication by reversible inhibition of viral HIV reverse transcriptase, which reverse transcribes viral RNA into DNA for insertion into the host DNA sequence (see Fig.

How does reverse transcriptase work in HIV?

When HIV infects a cell, reverse transcriptase copies the viral single stranded RNA genome into a double-stranded viral DNA. The viral DNA is then integrated into the host chromosomal DNA, which then allows host cellular processes, such as transcription and translation, to reproduce the virus.

What are the causes of reverse transcriptase resistance?

This results from mutations in the N-terminal polymerase domain of the reverse transcriptase that reduce the enzyme’s affinity or ability to bind to the drug . A prime example for this mechanism is the M184V mutation that confers resistance to lamivudine (3TC) and emtricitabine (FTC).

What happens when an NRTI is added to a viral DNA?

As a result, following incorporation of an NRTI or an NtRTI, the next incoming deoxynucleotide cannot form the next 5′–3′ phosphodiester bond needed to extend the DNA chain. Thus, when an NRTI or NtRTI is incorporated, viral DNA synthesis is halted, a process known as chain termination.