What is the Difference Between NNRTI and NRTI

The key difference between NNRTI and NRTI is that NNRTI works by non competitively inhibiting the reverse transcriptase of the HIV virus while NRTI works by competitively inhibiting the reverse transcriptase of the HIV virus.

NNRTI (non-nucleoside reverse transcriptase inhibitor) and NRTI (nucleoside reverse transcriptase inhibitor) are two classes of antiretroviral drugs. They are used for the treatment of AIDS (acquired immune deficiency syndrome). Both NNRTI and NRTI interfere with the process of RNA to DNA reverse transcription of the virus. However, their mechanisms are entirely different.

CONTENTS

1. Overview and Key Difference
2. What is NNRTI
3. What is NRTI
4. Similarities – NNRTI and NRTI
5. NNRTI vs NRTI in Tabular Form
6. Summary – NNRTI vs NRTI

What is NNRTI?

Non-nucleoside reverse transcriptase inhibitor (NNRTI) is a class of antiretroviral drugs used for the treatment of AIDS. NNRII works by non-competitively inhibiting the reverse transcriptase of the HIV virus. Antiretroviral drugs are classes of HIV drugs. NNRTI binds to and blocks HIV reverse transcriptase enzyme. HIV uses reverse transcriptase to convert its RNA to DNA. Blocking reverse transcriptase and reverse transcription prevents HIV from replicating.

The mechanism of action of this drug class is completely different from other antiretroviral drug classes. NNRTI drugs bind directly to HIV reverse transcriptase at a hydrophobic site remote from the enzyme’s active site to produce a conformational change that prevents substrate binding of an enzyme. They have greater antiviral activity than nucleoside analogue inhibitors and are better tolerated. Moreover, the resistance for this drug class emerges by single point mutations in the reverse transcriptase enzyme, which reduce the binding of the drugs to the hydrophobic binding site. They are highly effective when they are used in combination with at least two other antiretroviral drugs.

NNRTIs are the third class of antiretroviral drugs that were developed. This class of drugs was first described at the Rega Institute for Medical Research (Belgium). Furthermore, some examples of NNRTIs include Efavirenz, Nevirapine, Delavirdine, Etravirine, Rilpivirine, and Doravirine.

What is NRTI?

Nucleoside reverse transcriptase inhibitor (NRTI) is a class of antiretroviral drugs used for the treatment of AIDS. It also works by competitively inhibiting the reverse transcriptase of the HIV virus. It was the first class of antiretroviral drugs developed. NRTI drug class works in different ways, but one of the main ways is competing with reverse transcriptase for their interaction with HIV genetic material. These drugs have a nucleoside structure and depend on phosphorylation for activity. There are two types of HIV: HIV-1 and HIV-2. NRTIs are effective against both HIV-1 and HIV-2 types.

There are several FDA-approved NRTIs. They include Abacavir, Emtricitabine, Lamivudine, Tenofovir alafenamide, Tenofovir disoproxil fumarate, and Zidovudine. Most people with HIV infection take more than one NRTI at a time. Furthermore, NRTIs can induce mitochondrial impairment, which leads to a number of adverse events such as symptomatic lactic acidosis.

What are the Similarities Between NNRTI and NRTI?

• NNRTI and NRTI are two classes of antiretroviral drugs used for the treatment of AIDS.
• Both NNRTI and NRTI interfere with the process of RNA to DNA reverse transcription.
• Both are effective drug classes against the HIV-1 type.

What is the Difference Between NNRTI and NRTI?

NNRTI is a class of antiretroviral drugs used for the treatment of AIDS and works by non competitively inhibiting the reverse transcriptase of the HIV virus, while NRTI is a class of antiretroviral drugs used for the treatment of AIDS and works by competitively inhibiting the reverse transcriptase of HIV virus. Thus, this is the key difference between NNRTI and NRTI. Furthermore, NNRTI has greater antiviral activity and is better tolerated than NRTI.

The below infographic presents the differences between NNRTI and NRTI in tabular form for side-by-side comparison.

Summary – NNRTI vs NRTI

NNRTI and NRTI are two classes of antiretroviral drugs. NNRTI works by non-competitively inhibiting the reverse transcriptase of HIV virus, while NRTI works by competitively inhibiting the reverse transcriptase of HIV virus. So, this is the key difference between NNRTI and NRTI.

Reference:

1. “Non-Nucleoside Reverse Transcriptase Inhibitor (NNRTI): NIH.” Cinical Info.
2. Yoder, Kathleen. “Nucleoside/Nucleotide Reverse Transcriptase Inhibitors.” Healthline, Healthline Media.

Image Courtesy:

1. “Delavirdine synthesis” By Nuklear – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Abacavir 3d structure” By Giorgiogp2 – Own work (CC BY-SA 3.0) via Commons Wikimedia