Integrase and entry inhibitors

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Integrase and entry inhibitors

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A 26-year-old man presents to the clinic for evaluation of fever, fatigue, and sore throat, which have been ongoing for 2 weeks. He thinks he may have “mono.” The patient has had sexual intercourse with three partners over the past year and has been using condoms inconsistently. Temperature is 38.2°C (100.8°F), blood pressure is 110/85 mmHg, and pulse is 73/min. Physical examination reveals cervical and supraclavicular lymphadenopathy. The tonsils are erythematous but normal in size. An HIV PCR test is positive for HIV-1. The patient is started on an antiretroviral regimen of emtricitabine, tenofovir, and dolutegravir. What is the mechanism of action by which dolutegravir acts as an HIV medication?  


Entry inhibitors and integrase inhibitors are groups of medications that are used in HAART, or highly active antiretroviral therapy, which is the combination of medications used in the treatment of AIDS.

AIDS is caused by a retrovirus called human immunodeficiency virus, or HIV.

Entry inhibitors act by preventing the binding of HIV to the CD4+ cell receptors, thereby preventing its entry into the cell.

Integrase inhibitors inhibit the viral integrase enzyme, which is needed to incorporate the HIV proviral DNA into the host cell DNA.

HIV is a single-stranded, positive-sense, enveloped RNA retrovirus that targets cells in the immune system that have a molecule called CD4 on their membrane.

These include macrophages, dendritic cells, and especially CD4+ T-helper cells.

Normally, the CD4 molecule helps these cells attach to and activate other immune cells when there’s an infection.

HIV has 2 proteins, gp120 and gp41 that form a complex on its envelope, which it uses to attach to the CD4 molecules.

Next, it uses this complex to attach to a co-receptor on the immune cell before it can gain entry.

The most common co-receptor that HIV binds to the CXCR4 co-receptor on T-cells; or the CCR5 co-receptor found on T-cells, macrophages, monocytes, and dendritic cells.

When HIV binds to the CD4 and the co-receptors, the viral envelope fuses with the cell membrane of the immune cell, releasing its single-stranded RNA and some viral enzymes, like reverse transcriptase and integrase into the helpless host cell’s cytoplasm.


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  2. "Rang and Dale's Pharmacology" Elsevier (2019)
  3. "Goodman and Gilman's The Pharmacological Basis of Therapeutics, 13th Edition" McGraw-Hill Education / Medical (2017)
  4. "Metabolic, mitochondrial, renal and hepatic safety of enfuvirtide and raltegravir antiretroviral administration: Randomized crossover clinical trial in healthy volunteers" PLOS ONE (2019)
  5. "Structure of the CCR5 Chemokine Receptor-HIV Entry Inhibitor Maraviroc Complex" Science (2013)
  6. "HIV-1 Antiretroviral Drug Therapy" Cold Spring Harbor Perspectives in Medicine (2012)

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