Antiviral Drug Classes & Mechanisms of Action and MCQ for GPAT, NIPER JEE, NEETPG , Nursing Exams
Antiviral Drug Classes & Mechanisms of Action
| Class | Example Drugs | Target Virus | Mechanism of Action |
|---|---|---|---|
| 1. Entry Inhibitors | Maraviroc, Enfuvirtide | HIV | Block entry of virus into host cells. Maraviroc blocks CCR5 receptor; Enfuvirtide inhibits fusion of viral envelope. |
| 2. Reverse Transcriptase Inhibitors (RTIs) | NRTIs: Zidovudine, Lamivudine NNRTIs: Nevirapine, Efavirenz |
HIV | Inhibit reverse transcriptase enzyme which converts viral RNA to DNA. NRTIs mimic nucleosides; NNRTIs bind directly to RT. |
| 3. Integrase Inhibitors | Dolutegravir, Raltegravir | HIV | Inhibit integrase enzyme, blocking integration of viral DNA into host genome. |
| 4. Protease Inhibitors | Ritonavir, Lopinavir | HIV, HCV | Inhibit viral protease enzyme, preventing cleavage of viral polyproteins → blocks maturation. |
| 5. Neuraminidase Inhibitors | Oseltamivir, Zanamivir | Influenza A & B | Block neuraminidase enzyme → prevents release of new virions from infected cells. |
| 6. RNA Polymerase Inhibitors | Remdesivir, Sofosbuvir | SARS-CoV-2, HCV | Inhibit viral RNA-dependent RNA polymerase → prevent viral RNA replication. |
| 7. DNA Polymerase Inhibitors | Acyclovir, Ganciclovir | HSV, VZV, CMV | Inhibit viral DNA polymerase → block DNA replication. |
| 8. Capsid Inhibitors | Pleconaril | Enteroviruses | Block uncoating of virus by targeting capsid proteins. |
| 9. M2 Ion Channel Inhibitors | Amantadine, Rimantadine | Influenza A | Block M2 proton channel → inhibit viral uncoating. (Rarely used due to resistance) |
| 10. Monoclonal Antibodies | Palivizumab | RSV | Bind to viral surface proteins to neutralize virus or prevent attachment. |
Notes Summary
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HIV Drugs target multiple stages: entry (Maraviroc), fusion (Enfuvirtide), reverse transcription (NRTIs/NNRTIs), integration (INSTIs), maturation (protease inhibitors).
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Influenza Drugs inhibit neuraminidase (Oseltamivir) or M2 protein (Amantadine).
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Herpesviruses (HSV/CMV) are targeted by DNA polymerase inhibitors like Acyclovir.
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HCV and SARS-CoV-2 targeted by RNA polymerase inhibitors (Sofosbuvir, Remdesivir).
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Monoclonal antibodies provide passive immunity for specific viruses.
MCQs Based on Mechanism of Action
1. Which antiviral drug class inhibits the integration of viral DNA into the host genome?
A. NRTIs
B. Protease Inhibitors
C. Integrase Inhibitors
D. NNRTIs
Answer: C. Integrase Inhibitors
2. Which of the following drugs blocks viral entry by binding to the CCR5 receptor?
A. Dolutegravir
B. Lamivudine
C. Maraviroc
D. Oseltamivir Answer: C. Maraviroc
3. Oseltamivir works by:
A. Blocking viral reverse transcription
B. Inhibiting neuraminidase enzyme
C. Blocking CCR5 co-receptor
D. Inhibiting viral integration Answer: B. Inhibiting neuraminidase enzyme
4. Which class of drugs mimics nucleosides and terminates viral DNA synthesis?
A. NNRTIs
B. NRTIs
C. Protease inhibitors
D. Neuraminidase inhibitors Answer: B. NRTIs
5. Which of the following targets the RNA-dependent RNA polymerase in SARS-CoV-2?
A. Maraviroc
B. Remdesivir
C. Raltegravir
D. Zanamivir Answer: B. Remdesivir