Evidence of hypertriglyceridemia in managing HIV patients on efavirenz

Switch from efavirenz to nevirapine associated with resolution of efavirenz-related neuropsychiatric adverse events and improvement in lipid profiles

In a large HIV-specialty private practice, patients with undetectable or low-grade-positive viral loads with neuropsychiatric side effects or elevated lipids were switched from efavirenz-to nevirapine-based antiretroviral regimens. This is a retrospective analysis of virologic efficacy and changes in adverse neuropsychiatric effects and serum lipid levels after this switch. Forty patients were evaluated. Thirty-six had undetectable viral loads prior to the treatment switch, and their levels remained undetectable after the switch for a median of 25 months (range, 6 to 59 months). Four patients had persistently low-grade-positive viral loads before the switch; viral loads in two of the four patients remained low-grade-positive, while the levels in two patients became undetectable. Twenty patients reporting neuropsychiatric symptoms (depression, anxiety, or fatigue with or without sleep disturbances) before the switch demonstrated significant improvement, with complete resolution of symptoms in 15 patients. Four patients with isolated sleep disturbances had significant improvement. No rash developed in any patient during the switch. Mean lipid levels improved significantly following the switch. Mean total cholesterol decreased 17.8 mg/dL; low-density lipoprotein cholesterol decreased 25.5 mg/dL; triglycerides decreased 70.1 mg/dL; and high-density lipoprotein cholesterol increased 5.3 mg/dL (all p < 0.05). These results demonstrate that patients who are virologically controlled on efavirenz-containing regimens with treatment-associated side effects can be successfully switched to nevirapine-containing therapy with maintenance of virologic control, reduction in neuropsychiatric side effects, and improvement in dyslipidemia.

Exercise training in HIV-1-infected individuals with dyslipidemia and lipodystrophy

PURPOSE

Highly active antiretroviral therapy has improved the prognosis of human immuno deficiency virus type 1 (HIV-1)-infected individuals, but it has been associated with the development of metabolic and fat distribution abnormalities known as the lipodystrophy syndrome. This study tested the hypothesis that aerobic exercise training added to a low-lipid diet may have favorable effects in HIV-1-infected individuals with dyslipidemia and lipodystrophy.

METHODS

Thirty healthy subjects, carriers of HIV-1, with dyslipidemia and lipodystrophy, all of whom were using protease inhibitors and/or non-nucleoside reverse transcriptase inhibitors, were randomly assigned to participate in either a 12-wk program of aerobic exercise or a 12-wk stretching and relaxation program. All subjects received recommendations for a low-lipid diet. Before and after intervention, peak oxygen uptake, body composition, CD4, viral load, lipid profile, and plasma endothelin-1 levels were measured.

RESULTS

Peak oxygen uptake increased significantly in the diet and exercise group (mean +/- SD: 32 +/- 5 mL x kg(-1) x min(-1) before; 40 +/- 8 mL x kg(-1) x min(-1) after) but not in the diet only group (34 +/- 7 mL x kg(-1) x min(-1) before; 35 +/- 8 mL x kg(-1) x min(-1) after). Body weight, body fat, and waist-to-hip ratio decreased significantly and similarly in the two groups. There were no significant changes in immunologic variables in either group. Likewise, plasma triglycerides, total cholesterol, and HDL cholesterol levels did not change significantly in either group. Plasma endothelin-1 levels were elevated in both groups and presented no significant changes during the study.

CONCLUSION

HIV-seropositive individuals with lipodystrophy and dyslipidemia submitted to a short-term intervention of low-lipid diet and aerobic exercise training are able to increase their functional capacity without any consistent changes in plasma lipid levels.

Induction of CYP3A4 by efavirenz in primary human hepatocytes: comparison with rifampin and phenobarbital

The antiretroviral agent efavirenz enhances the systemic clearance of coadministered drugs that are cytochrome P450 (CYP) 3A4 substrates. The mechanism of the apparent increase in CYP3A4 activity by efavirenz and the magnitude of change relative to other known inducers are not known. The authors tested the hypothesis that increased enzymatic activity by efavirenz entails CYP3A4 induction and activation of the human pregnane X receptor (hPXR), a key transcriptional regulator of CYP3A4. Employing primary cultures of human hepatocytes, they compared the CYP3A4 inductive effects of efavirenz (1-10 microM) to rifampin (10 microM) and phenobarbital (2 mM). A cell-based reporter assay was employed to assess hPXR activation. The authors observed that efavirenz caused a concentration-dependent CYP3A4 induction and hPXR activation. Based on the CYP3A4 activity assay, the average magnitude of induction by efavirenz (5-10 microM) was approximately 3- to 4-fold. In comparison, phenobarbital (2 mM) and rifampin (10 microM) caused a 5- and 6-fold induction, respectively.