What do nucleoside analog antiviral drugs inhibit?

However, they have activity against both DNA dependent and RNA dependent DNA polymerases. They are believed to inhibit viral replication by several mechanisms, either by competitive inhibition of the viral polymerase or by DNA chain termination.

Which drugs are nucleoside analogs?

Actually, nucleoside analogues are a large class of agents that include drugs for cancer (cytarabine, gemcitabine, mercaptopurine, azacytidine, cladribine, decitabine, fluorouracil, floxuridine, fludarabine, nelarabine), and rheumatologic diseases (azathioprine, allopurinol) and even bacterial infections (trimethoprim) …

Is entecavir a nucleoside or nucleotide?

Entecavir, a new guanosine nucleoside analogue with specific activity against HBV DNA polymerase, represents a third agent within the nucleoside/nucleotide HBV polymerase inhibitor class.

Which antiviral drug is thymidine analog?

Trifluridine☆ A thymidine analog that inhibits DNA polymerase activity, trifluridine is an antiviral drug used primarily as a treatment of Herpes Simplex Virus (HSV-1 and HSV-2) and vaccinia virus [Drug Facts and Comparison (2001)].

Is acyclovir a nucleoside analog?

Acyclovir (9-[2-hydroxymethyl]guanine) is a nucleoside analog that selectively inhibits the replication of herpes simplex virus types 1 and 2 (HSV-1, HSV-2) and varicella-zoster virus (VZV).

How do nucleoside analogues work?

Nucleoside analogues mimic endogenous nucleosides, exploiting cellular metabolism and becoming incorporated into both DNA and RNA. This property makes nucleoside analogues effective at inhibiting viral replication and stopping cancer cell proliferation.

Is AZT a nucleoside analog?

Nucleoside analogue reverse transcriptase inhibitors including didanosine (ddI), lamivudine (3TC), stavudine (d4T), zalcitabine (ddC), and zidovudine (ZDV, formerly AZT) are used to treat human immunodeficiency virus (HIV) infection.

Is tenofovir a nucleoside analogue?

Tenofovir, a novel nucleotide analog, belongs to the class of acyclic nucleoside phosphonates. Tenofovir is phosphorylated in situ to the virologically active tenofovir diphosphate. Tenofovir diphosphate inhibits human immunodeficiency virus (HIV-1 and HIV-2) DNA polymerases.

Which drug is not a nucleoside analog?

The widely used vasodilator and antiarrhythmic agents, hydralazine [38], and procainamide [39], have been demonstrated to be non-nucleoside analog DNMT inhibitors. These drugs exhibit less cytotoxicity because they do not require incorporation into DNA [18].

Is Remdesivir a nucleoside analog?

Remdesivir is a nucleoside analog, one of the oldest classes of antiviral drugs. It works by blocking the RNA polymerase that coronaviruses and related RNA viruses need to replicate their genomes and proliferate in the host body.

Is valacyclovir a nucleoside analog?

Acting as an oral prodrug, valacyclovir is converted in vivo to acyclovir. Acyclovir, a nucleoside analog, is phosphorylated by virally-encoded thymidine kinase and subsequently by cellular enzymes, yielding acyclovir triphosphate, which competitively inhibits viral DNA polymerase. (See “Acyclovir: An overview”.)

Is AZT an example of nucleoside analogues?

Why are nucleoside analogs active only against replicating viruses?

Why are nucleoside analogs active only against replicating viruses? Nucleoside analogs work by being incorporated into growing strands of DNA/RNA. This indirectly shuts down further extension of these chains. However, new strands of viral DNA/RNA are only being created when the virus is replicating.

How does AZT inhibit the RT enzyme?

After being activated by phosphorylation in vivo, AZT inhibits HIV replication by blocking a critical HIV enzyme called reverse transcriptase. This enzyme uses the virus’s RNA genome as a template to build a DNA version that can be inserted into the host’s genome.

Is AZT a protease inhibitor?

AZT is used in combination with several other anti-HIV drugs, usually including drugs from different classes, such as protease inhibitors and/or non-nukes (non-nucleoside reverse transcriptase inhibitors). Combinations such as this are called antiretroviral therapy, or ART.

What is nucleoside analog reverse transcriptase inhibitors?

Nucleoside reverse transcriptase inhibitors (NRTIs) are structural nucleoside analogues of DNA nucleotides which prevent reverse transcription of the HIV genome, thereby inhibiting the action of HIV-1 RT and viral replication .

What type of inhibitor is remdesivir?

Remdesivir (RDV) is an investigational compound with a broad spectrum of antiviral activities against RNA viruses, including severe acute respiratory syndrome–CoV and Middle East respiratory syndrome (MERS–CoV). RDV is a nucleotide analog inhibitor of RNA-dependent RNA polymerases (RdRps).

What class of drug is remdesivir?

Remdesivir is in a class of medications called antivirals. It works by stopping the virus from spreading in the body.

What is the difference between valacyclovir and acyclovir?

Valacyclovir (Valtrex) and acyclovir (Zovirax) are antiviral drugs that work by interfering with viral DNA replication. Both drugs target the same viruses but valacyclovir provides longer duration of action, therefore, doses can be taken fewer times every day – this is the only real advantage.

What do nucleotide analogues do?

Nucleoside and nucleotide analogues can be used in therapeutic drugs, including a range of antiviral products used to prevent viral replication in infected cells.

What are nucleos (t) ide analog inhibitors of HBV?

Nucleos(t)ide analog inhibitors of HBV reverse transcriptase are prodrugs that need to be converted in their active triphosphate forms by cellular kinases. Activated nucleos(t)ide inhibitors compete with natural nucleotide substrates for incorporation into the elongating DNA chain.

What is the best nucleoside analogue for hepatitis B?

They are administered orally, and most of them have an excellent tolerance and safety profile. Lamivudine is the only nucleoside analogue licensed for chronic hepatitis B.

Which nucleoside/nucleotide inhibitors of HBV polymerase inhibit protein priming?

Approved nucleoside/nucleotide inhibitors of the HBV polymerase include lamivudine, adefovir, telbivudine, entecavir and tenofovir. Although most of them target DNA elongation, guanosine and adenosine analogs (e.g. entecavir and tenofovir, respectively) also impair protein priming.

What are the antiviral nucleoside analogs?

Other antiviral nucleoside analogues are negative enantiomers (L-forms: lamivudine, emtricitabine, telbivudine) of the natural (D-form) nucleosides and interfere with replication, partially because of steric hindrance when they are taken up by the viral polymerase or added to the DNA molecule.