Medicine & USMLE

Entry Inhibitors (Enfuvirtide, Maraviroc)

  1. Oseltamivir, Zanamivir
  2. Acyclovir (Famciclovir, Valacyclovir)
  3. Ganciclovir
  4. Foscarnet
  5. Cidofovir
  6. NRTIs
  7. NNRTIs
  8. Integrase Inhibitors
  9. Protease Inhibitors
  10. Entry Inhibitors (Enfuvirtide, Maraviroc)
  11. NS5A Inhibitors
  12. NS5B Inhibitors
  13. NS3/4A Inhibitors


Enfuvirtide and Maraviroc are entry inhibitors used to treat HIV. Enfuvirtide is an entry inhibitor that works by binding to gp41, a protein expressed on the HIV envelope. By doing so, enfuvirtide inhibits the fusion between viral and host cell membranes. On the other hand, Maraviroc is an entry inhibitor that attaches to the CCR-5 receptor expressed on macrophages and other immune cells. This blocks the HIV envelope protein, gp120, from binding to CCR-5 to mediate attachment and infection. By doing this, Maraviroc prevents HIV from attaching to cells, ultimately preventing entry. Both Enfuvirtide and Maraviroc work to block HIV entry into cells and can be used to treat patients with HIV. Side effects of enfuvirtide include peripheral neuropathy and a skin reaction at the injection site, while maraviroc can cause hepatotoxicity.

Key Points

  • Enfuvirtide
    • Mechanism
      • Binds gp41
        • Inhibits viral membrane fusion with host CD4+ T-cells (furv = fusion - FA mnemonic)
        • Prevents viral entry
    • Indications
      • HIV
        • Active against HIV-1 but not HIV-2
    • Adverse Effects
      • Skin reaction at injection site
      • Peripheral neuropathy
    • Maraviroc
      • Mechanism
        • Bind CCR-5 on surface of T-cells/monocytes
          • Occupies CCR5 and blocks gp120 from attaching
          • Prevents viral entry
      • Indications
        • HIV
          • Active against both HIV-1 and HIV-2
      • Adverse Effects
        • Hepatotoxicity