A 25-year-old man comes to the office for follow-up. He was diagnosed with HIV several weeks ago following a hospitalization for Pneumocystis pneumonia. He has no other medical problems. His HIV drug susceptibility report shows no evidence of resistance. The patient's treatment regimen includes a drug that is structurally unrelated to nucleosides and is not phosphorylated intracellularly. The drug acts within the cytoplasm of infected cells to inhibit the synthesis of viral DNA from the RNA template. Which of the following agents was most likely used in this patient?

Question

A 25-year-old man comes to the office for follow-up.  He was diagnosed with HIV several weeks ago following a hospitalization for Pneumocystis pneumonia.  He has no other medical problems.  His HIV drug susceptibility report shows no evidence of resistance.  The patient's treatment regimen includes a drug that is structurally unrelated to nucleosides and is not phosphorylated intracellularly.  The drug acts within the cytoplasm of infected cells to inhibit the synthesis of viral DNA from the RNA template.  Which of the following agents was most likely used in this patient?

Quizplus · Accepted Answer

11ec160b_3bf2_0214_9249_51e13500b380_MD0001_00 Retroviral reverse transcriptase inhibitors prevent the synthesis of viral DNA from the RNA template. Nonnucleoside reverse transcriptase inhibitors (NNRTIs) do not require activation via intracellular phosphorylation. The more common NNRTIs include nevirapine and efavirenz. They are best used in conjunction with other antiretroviral agents for the treatment of HIV infection. Adverse effects are common with NNRTIs. Abrupt-onset flulike symptoms, abdominal pain, jaundice, or fever may indicate potentially life-threatening hepatic failure (most likely to occur within the first 6 weeks of NNRTI therapy). Life-threatening skin reactions (eg, Stevens-Johnson syndrome, toxic epidermal necrolysis) have also been observed. (Choices A and E) Zidovudine and emtricitabine are nucleoside reverse transcriptase inhibitors (NRTIs). In general, NRTIs must be converted into their monophosphate forms by a cellular kinase (cellular thymidine kinase) before they can be converted into pharmacologically active triphosphate forms. (Choice B) Enfuvirtide is an HIV fusion inhibitor that binds to HIV envelope gp41 and blocks the conformational changes necessary for the fusion of viral and cellular membranes. Through this mechanism, enfuvirtide denies the HIV genome entry into uninfected CD4⁺ T-cells. Its main site of action is outside the cytoplasm. (Choice D) Ritonavir is an inhibitor of HIV protease that prevents assembly and maturation of the virus. Nonfunctional, noninfectious virions are produced instead. Reverse transcription is not affected. Educational objective: Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are antiretroviral drugs that do not require activation via intracellular phosphorylation. The more common NNRTIs include nevirapine and efavirenz.

A 25-Year-Old Man Comes to the Office for Follow-Up