Comparative Effectiveness and Toxicity of Statins Among HIV-Infected Patients.

BACKGROUND: dyslipidemia is common and is often treated with 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors (statins). Little is known about the comparative effectiveness of statins among human immunodeficiency virus (HIV)-infected patients. This study compared the effectiveness and toxicity of statins among HIV-infected patients in clinical care. METHODS: we conducted a retrospective cohort study of patients starting their initial statin medications at 2 large HIV clinics (N = 700). The primary observation was change in lipid levels during statin therapy. Secondary observations included whether individualized National Cholesterol Education Program (NCEP) goals for low density lipoprotein cholesterol (LDL-C) and non-high density lipoprotein cholesterol (non-HDL-C) levels were reached, and toxicity rates. We used linear regression to examine change in lipid levels, controlling for baseline lipid values and demographic and clinical characteristics. We conducted secondary analyses using propensity scores to address confounding by indication. RESULTS: the most commonly prescribed statins were atorvastatin (N = 303), pravastatin (N = 280), and rosuvastatin (N = 95). One year after starting a statin therapy, patients who received atorvastatin or rosuvastatin had significantly greater decreases in total cholesterol, LDL-C, and non-HDL-C than patients on pravastatin. The likelihood of reaching NCEP goals for LDL-C levels was higher with the use of rosuvastatin (OR 2.1; P = .03) and atorvastatin (odds ratio [OR], 2.1; P = .001) compared with that of pravastatin. The likelihood of reaching NCEP goals for non-HDL-C levels was higher for rosuvastatin (OR 2.3; P = .045) but not atorvastatin (OR, 1.5; P = .1) compared with pravastatin. Toxicity rates were similar for all 3 statins: 7.3% for atorvastatin, 6.1% for pravastatin, and 5.3% for rosuvastatin. CONCLUSIONS: our findings suggest that atorvastatin and rosuvastatin are preferable to pravastatin for treatment of HIV-infected patients with dyslipidemia, due to greater declines in total cholesterol, LDL-C, and non-HDL-C, with similar lower toxicity rates.

Pharmacokinetics of nelfinavir and indinavir in HIV-1-infected pregnant women.

BACKGROUND: Protease inhibitor (PI)-based combination antiretroviral therapy is often indicated for treatment of maternal HIV disease, but little is known about PI pharmacokinetics during pregnancy. Increased cytochrome P450 activity may affect the disposition of PI and decrease drug exposure. METHODS: Steady-state PI pharmacokinetics, measured by the area under the plasma concentration versus time curve (AUC(tau)), were evaluated in women on stable antiretroviral regimens containing nelfinavir (n = 9) or indinavir (n = 4) with or without ritonavir (n = 2) during the second and third trimesters of pregnancy and postpartum. Cytochrome P450 activity was assessed by measuring the urine 6 beta-hydroxycortisol to cortisol ratio (6 beta-OHF/F). RESULTS: AUC(tau) in women on indinavir alone decreased and 6 beta-OHF/F ratios increased during pregnancy compared with postpartum control values (n = 2). Nelfinavir results demonstrated no clear change and were highly variable. CONCLUSIONS: The results for indinavir suggest that metabolic induction occurs during pregnancy, which apparently resolves spontaneously postpartum. This may warrant dosage adjustment during pregnancy. This induction is offset by concomitant use of ritonavir. Nelfinavir results were variable and, therefore, the impact of pregnancy on nelfinavir disposition was not fully determined.

The effects of cannabinoids on the pharmacokinetics of indinavir and nelfinavir.

BACKGROUND AND OBJECTIVES: The use of cannabinoids for appetite stimulation and the management of wasting and antiretroviral side-effects has become a common practice in the care of HIV-infected individuals. We present pharmacokinetic data from a randomized placebo-controlled study designed to evaluate the metabolic effects of smoked marijuana and dronabinol in HIV-infected patients receiving indinavir (IDV) or nelfinavir (NFV). METHODS: Subjects on stable regimens containing IDV 800 mg every 8 h (n = 28) or NFV 750 mg three time a day (n = 34) were randomized to one of three treatment arms: 3.95% THC marijuana cigarettes, dronabinol 2.5 mg capsules or placebo capsules administered three times daily. Serial blood sampling was performed at baseline and on day 14 of treatment. The changes in NFV and IDV pharmacokinetics were measured as the median percentage change from baseline. RESULTS: At day 14, the 8-h area under the curve (AUC(8)) changed by -10.2% (P = 0.15), maximum concentration (C(max)) by -17.4% (P = 0.46), and minimum concentration (C(min)) by -12.2% (P = 0.28) for patients in the NFV marijuana arm (n = 11). Similar decreases had occurred by day 14 among patients in the IDV marijuana arm (n = 9): AUC8 had changed by -14.5% (P = 0.074), C(max) by -14.1% (P = 0.039), and C(min) by -33.7% (P = 0.65). CONCLUSION: Despite a statistically significant decrease in C(max) of IDV in the marijuana arm, the magnitude of changes in IDV and NFV pharmacokinetic parameters in the marijuana arm are likely to have no short-term clinical consequence. The use of marijuana or dronabinol is unlikely to impact antiretroviral efficacy.

Population pharmacokinetics of enfuvirtide in pediatric patients with human immunodeficiency virus: searching for exposure-response relationships.

OBJECTIVE: Our objective was to describe the population pharmacokinetics and pharmacodynamics of enfuvirtide acting on viral ribonucleic acid in children with human immunodeficiency virus 1. METHODS: A 1-compartment population pharmacokinetic model with first-order absorption and elimination was fit to subcutaneous and intravenous dose pharmacokinetic data from a 2-part study, as follows: an intensive-sample pharmacokinetic design (observed dose) (subcutaneous and intravenous, n = 12) followed by a sparse-sample design (unobserved dose) (subcutaneous, n = 15). The parameters of this model are clearance (CL), volume of distribution (V), absorption rate (k(a)), bioavailability (F), and both interindividual and residual variability. Plasma ribonucleic acid concentrations over time were used to build a population viral pharmacodynamics model with the following parameters: viral clearance (CL(v)), initial viral concentration (A(0)), duration (tau) and rate (R) of preinfected cell-based viral input after enfuvirtide was begun, and interindividual and residual variability. RESULTS: The mean population CL and V of enfuvirtide for a child with a mean body weight of 21.3 kg were 1.42 L/h and 5.67 L, respectively. Patient weight affected CL and V. Volume appeared to differ between intensive and sparse sampling occasions, and this difference also affected the residual error variance. Time after the beginning of therapy did not significantly affect any pharmacokinetic parameter, supporting the absence of metabolic induction and inhibition. Although trends were present, no statistically significant relationship was seen between any pharmacokinetic-based individual enfuvirtide exposure measure and any virologic response measure. CONCLUSIONS: Regarding pharmacokinetics and pharmacodynamics, no statistically significant correlation between exposure measures and viral clearance was observed.