Analyzing Sleep Abnormalities in HIV‐Infected Patients Treated with Efavirenz

Cognitive behavior therapy for chronic insomnia occurring within the context of medical and psychiatric disorders

Insomnia is a pervasive problem for many patients suffering from medical and psychiatric conditions. Even when the comorbid disorders are successfully treated, insomnia often fails to remit. In addition to compromising quality of life, untreated insomnia may also aggravate and complicate recovery from the comorbid disease. Cognitive behavior therapy for insomnia (CBT-I) has an established efficacy for primary insomnia, but less is known about its efficacy for insomnia occurring in the context of medical and psychiatric conditions. The purpose of this article is to present a rationale for using CBT-I in medical and psychiatric disorders, review the extant outcome literature, highlight considerations for adapting CBT-I procedures in specific populations, and suggest directions for future research. Outcome studies were identified for CBT-I in mixed medical and psychiatric conditions, cancer, chronic pain, HIV, depression, posttraumatic stress disorder, and alcoholism. Other disorders discussed include: bipolar disorder, eating disorders, generalized anxiety, and obsessive compulsive disorder. The available data demonstrate moderate to large treatment effects (Cohen's d, range=0.35-2.2) and indicate that CBT-I is a promising treatment for individuals with medical and psychiatric comorbidity. Although the literature reviewed here is limited by a paucity of randomized, controlled studies, the available data suggest that by improving sleep, CBT-I might also indirectly improve medical and psychological endpoints. This review underscores the need for future research to test the efficacy of adaptations of CBT-I to disease specific conditions and symptoms.

Are Adverse Events of Nevirapine and Efavirenz Related to Plasma Concentrations?

Objective

The relationships between adverse events (AEs) and plasma concentrations of nevirapine (NVP) and efavirenz (EFV) were investigated as part of the large, international, randomized 2NN study.

Methods

Treatment-naive, HIV-1-infected patients received NVP (once or twice daily), EFV or their combination, each in combination with lamivudine and stavudine. Blood samples were collected on day 3 and weeks 1, 2, 4, 24 and 48. Concentrations of NVP and EFV were quantitatively assessed by a validated HPLC assay. Individual Bayesian estimates of the area under the plasma concentration–time curve over 24 h (AUC24h), and minimum and maximum plasma concentrations (Cmin and Cmax) as measures for drug exposure of NVP and EFV, were generated using a previously developed population pharmacokinetic model. Pharmacokinetic parameters were compared for patients with and without central nervous system (CNS) and psychiatric AEs, hepatic events, liver enzyme elevations (LEEs) and rash. Furthermore, it was investigated whether a clear cut-off for a pharmacokinetic parameter could be identified above which the incidence of AEs was clearly increased. AEs were also related to demographic parameters and baseline characteristics.

Results

In total, from 1077 patients, NVP (3024 samples) and EFV (1694 samples) plasma concentrations and AE data (825 observations) were available. For all patients Cmin, Cmax and AUC24h were determined. When corrected for known covariates of gender, CD4 cell count at baseline, region, hepatitis coinfection and possible interactions between these factors, no significant associations between AEs and any tested exposure parameter of NVP was observed. Also, no target Cmin value, above which patients were at increased risk for AEs, could be established. On the other hand, geographical region, hepatitis coinfection, CD4 cell count and gender were found to be significantly related with the incidence of CNS and psychiatric AEs, hepatic events, LEEs and rash during the treatment with NVP. The occurrence of elevated liver enzymes during the first 6 weeks in the EFV-containing arm was significantly ( P=0.036) correlated to the exposure of EFV (Cmin). Only hepatitis coinfection impacted on LEEs during the first 6 weeks of treatment. With an EFV Cmin above 2.18 mg/l during the induction phase, patients were 4.4 (range 1.3–15.5) times more at risk for elevated liver enzymes. No other correlations between AEs and EFV pharmacokinetics or patient characteristics could be identified.

Conclusions

Pharmacokinetic parameters of NVP did not have a relationship to AEs in the 2NN trial when corrected for known covariates. The value of periodical drug monitoring of NVP as a way to prevent toxicity is therefore limited. Treating physicians should instead focus on factors that are more predictive of AEs (gender, CD4 count and hepatitis coinfection). High EFV Cmin levels resulted in elevated liver enzyme values during the first 6 weeks of treatment. Regular measurement of EFV levels and liver enzymes at the start of therapy may therefore be advised.

Long-Term Neuropsychiatric Disorders on Efavirenz-Based Approaches

BACKGROUND

Efavirenz has been associated with neuropsychiatric disorders, although little is known about its long-term toxicity.

OBJECTIVE

To assess neuropsychiatric disorders and their relation to efavirenz plasma levels as well as quality of life, psychologic status, and adherence in HIV-infected patients on long-term efavirenz-based antiretroviral therapy.

METHODS

Cross-sectional study comparing 60 patients on an efavirenz-based approach (EFV group) and 60 patients on a protease inhibitor-containing regimen (PI group) for at least 1 year. Adverse events, efavirenz plasma levels, quality of life, psychologic status, and adherence were assessed.

RESULTS

The mean time on treatment was 91.1 +/- 39.5 weeks in the EFV group and 119.9 +/- 67.4 weeks in the PI group. Mild dizziness, sadness, mood changes, irritability, lightheadedness, nervousness, impaired concentration, abnormal dreams, and somnolence were reported more frequently in the EFV group than in the PI group (P < 0.05). Forty-nine of 60 patients presented with therapeutic efavirenz plasma levels (range: 1.0-4.0 mg/L). Efavirenz plasma levels were similar in subjects with and without neuropsychiatric disorders. No significant differences were found between the EFV group and the PI group regarding quality of life and psychologic status. Sixty percent of patients in the EFV group and 55% in the PI group reported adherence >/=95%.

CONCLUSIONS

Mild and clinically tolerable neuropsychiatric disorders may persist in patients after a mean of 2 years using an efavirenz-based approach. Quality of life and psychologic status remained good in both study groups. Interventions to enhance long-term adherence should be applied in clinical practice.

Influence of 516G>T polymorphisms at the gene encoding the CYP450-2B6 isoenzyme on efavirenz plasma concentrations in HIV-infected subjects

We examined 516G>T polymorphisms at the gene encoding the cytochrome P450 in 100 human immunodeficiency virus-positive subjects who were receiving efavirenz (EFV). Elevated plasma EFV concentrations were found in 40% of subjects with the polymorphic homozygous genotype and 19% of subjects with the heterozygous genotype. Conversely, 20% of subjects with the wild-type genotype had subtherapeutic concentrations of EFV. CYP2B6-516 genotyping may help to identify subjects who have plasma EFV concentrations that are outside of the therapeutic range.

Efavirenz for HIV-1 infection in adults: an overview

Efavirenz (Sustiva), Bristol-Myers Squibb) is a non-nucleoside reverse transcriptase inhibitor that has been used successfully since the late 1990s to treat HIV-1 infection, and has since become a cornerstone of antiretroviral therapy. The efficacy and potency of efavirenz has been established in many clinical trials and cohort studies, where it has been compared with unboosted or ritonavir (Norvir, Abbott Laboratories Ltd)-boosted protease inhibitors, nevirapine (Viramune, Boehringer Ingelheim Ltd); and three nucleoside analog-based regimens. Pharmacokinetics allowing for a convenient once-daily administration make efavirenz one of the first agents to be included in once-daily regimens. Tolerability of efavirenz is satisfactory, although CNS-related toxicity can occur, and is still poorly understood. New insights into the pharmacokinetics of efavirenz could help to manage this unwanted toxicity. This drug profile will examine the principal data concerning the efficacy, pharmacokinetics and safety that have made efavirenz a standard of care in HIV-1 therapy, and will comment on new data that could change the way efavirenz is used in the near future.