• This study compares CYP3A enzyme activity in HIV positive persons who are on ritonavir with subjects not taking antiretrovirals.
  
  
• Cytochrome CYP3A is the major liver enzyme that metabolizes PIs and NNRTIs.
  
  
• Ritonavir inhibits CYP3A and acutely increases levels of other HIV medications.
  
  
• Chronic ritonavir use induces CYP3A and thus may increase metabolism of other medications. The presence of liver disease may further modify this effect.
  

• Men on ritonavir (>400 mg/day, i.e., not on Kaletra) OR on no antiretrovirals.
  
  
• Chronic viral hepatitis or normal liver function (no decompensated liver disease).
  
  
• No active substance abuse, active alcoholism, or in methadone treatment.
  
  
• Not on other medications which affect CYP3A activity (we will screen).
  
  
• Exclusion criteria for this pilot study were chosen to minimize the known effect of gender and race on CYP3A activity.
  

• Two separate overnight stays in the GCRC (CSU) to monitor drug levels for 24 hours. The two GCRC admissions will occur 1-4 weeks apart.
  
  
• Administration of a single dose of IV or oral midazolam (Versed), which is metabolized by CYP3A to measure enzyme activity by clearance of midazolam metabolites.
  
  

• Participation in this study carries no direct benefit to subjects other than being tested for chronic hepatitis which has been recommended for persons with HIV infection.
  
  
• These results may provide valuable information about the function of the major enzyme systems responsible for drug metabolism (clearing drugs) in humans with HIV infection and may help increase safety and efficacy of antiretroviral treatments for HIV.
  

To find out more about the Cytochrome (CYP3A) study, call:
(617) 636-3636.

Privacy and confidentiality are strictly maintained.

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