WBR0392

Author	[[PageAuthor::Serge Korjian M.D. (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pharmacology
Sub Category	SubCategory::Infectious Disease
Prompt	[[Prompt::A 35-year-old HIV-positive man presents to the infectious disease clinic for a routine follow-up. His most recent CD4 count 3 months ago was 670 cells/mm3 and his viral load was low to undetectable. At the time, the physician did not initiate high active antiretroviral therapy (HAART). Over the past month, the patient had been admitted twice to the hospital for a community-acquired pneumonia and for a gastroenteritis. His current lab results are remarkable for a CD4 of 231 cells/mm3 and a viral load of 325,000 copies/ml. Given his current lab findings, the infectious disease physician decides to initiate HAART for this patient. Which of the following drug combinations is most suitable for this patient?]]
Answer A	AnswerA::Tenofovir + emtricitabine + abacavir
Answer A Explanation	AnswerAExp::This combination has 3 NRTIs, a combination that is usually not recommended.
Answer B	AnswerB::Darunavir + raltegravir + lamivudine
Answer B Explanation	AnswerBExp::This combination has only 1 NRTI, which is usually not recommended. Darunavir is a protease inhibitor and raltegravir is an integrase inhibitor.
Answer C	AnswerC::Efavirenz + tenofovir + nevirapine
Answer C Explanation	AnswerCExp::This combination has only 1 NRTI, which is is usually not recommended. Efavirenz and nevirapine are both NNRTIs.
Answer D	AnswerD::Ritonavir + tenofovir + lopinavir
Answer D Explanation	AnswerDExp::This combination has only 1 NRTI. Ritonavir and lopinavir are both protease inhibitors.
Answer E	AnswerE::Raltegravir + tenofovir + emtricitabine
Answer E Explanation	AnswerEExp::This combination is most suitable because it includes 2 NRTIs (tenofovir + emtricitabine) and 1 integrase inhibitor.
Right Answer	RightAnswer::E
Explanation	[[Explanation::Highly active antiretroviral therapy (HAART) was introduced following the failure of earlier early regimens that consisted of only 2 drugs to sustain a therapeutic benefit. HAART consists of 3 or more therapeutic agents and is associated with a remarkable improvement in clinical outcomes among HIV-positive patients. The CD4 count and viral load are the two lab tests that determine the optimal timing for initiation of HAART. A CD4 count below 350 cells/mm3 or any AIDS-defining illness indicate the need for therapy. Viral load >100,000 copies/ml is not considered an absolute indication for treatment, and physicians may delay initiation of therapy depending on the CD4 counts. The recommended regimens include a combination of 2 nucleoside reverse transcriptase inhibitors (NRTIs) plus either a non-nucleoside reverse transcriptase inhibitor (NNRTI), a protease inhibitor, or an integrase inhibitor. The most commonly prescribed combinations include: Efavirenz + tenofovir + emtricitabine Ritonavir-boosted atazanavir + tenofovir + emtricitabine Ritonavir-boosted darunavir + tenofovir + emtricitabine Raltegravir + tenofovir + emtricitabine Educational Objective: HAART consists of 3 or more agents including a combination of 2 nucleoside reverse transcriptase inhibitors (NRTIs) plus either a non-nucleoside reverse transcriptase inhibitor (NNRTI), a protease inhibitor, or an integrase inhibitor. References: Piacenti FJ. An update and review of antiretroviral therapy. Pharmacotherapy. 2006;26(8):1111-33. U.S. Department of Health and Human Services. Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents. 2009. First Aid 2014 page 193]]
Approved	Approved::Yes
Keyword	WBRKeyword::HAART, WBRKeyword::HIV, WBRKeyword::AIDS, WBRKeyword::CD4 count, WBRKeyword::HIV drugs
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::