JH is a 60-year-old-man who is seen in clinic for follow up after initial testing confirmed positive for HIV infection. His HIV RNA is 1,500,000 copies/mL and CD4+ T-cell count is 90 cells/mm3. He has no documented opportunistic infections. No resistance mutations were identified. His HLA-B*5701 is negative. He has NKDA and has a Clcr of 80 ml/min. Which of the following prophylaxis regimens would be required?
D. Trimethoprim/sulfamethoxazole plus azithromycin
E. No prophylaxis is required
Answer with rationale:
HIV management is becoming a major component of primary care. I spoke to a former resident of mine a few weeks ago who informed me that the institution was hiring a primary care pharmacist with some HIV training as opposed to vice versa. There are so many effective single tablet regimens available that are very well tolerated! However, knowing how to provide prophylaxis when patient's have low CD4 counts are crucial to avoid an opportunistic infection.
The answer is A (trimethoprim/sulfamethoxazole). Since this patient's CD4 count is less than 200 cells/mm3, prophylaxis vs. Pneumocystis jirovecii pneumonia (PJP) is required for which trimethoprim/sulfamethoxazole would be appropriate. Additionally, his actual CD4 is below 100 cells/mm3 which would then require prophylaxis vs. Toxoplasmosis gondii. Fortunately, trimethoprim/sulfamethoxazole also provides prophylaxis vs. this organism. Rifampin is only used as prophylaxis in close contacts of patients with N. meningitidis when meningitis is confirmed. Answers C and D are incorrect as azithromycin only provides prophylaxis vs. MAC which is not required at this time. Answer E is incorrect as anytime the CD4 count is below 200 cells/mm3 prophylaxis is required.
This question also has some extra "noise" that often will present itself in an exam. Sometimes extra information is provided in a question that will have nothing to do with answering the question. Knowing that the patient is HLA-B*5701 negative is helpful but only when selecting the actual HIV regimen (abacavir could be part of regimen).
Have a great weekend!