The dual modulatory effects of efavirenz on GABAA receptors are mediated via two distinct sites

Safety of low dose efavirenz regimen in Indian adults with HIV-1 infection: Insights from a phase 4 interventional randomised trial

BACKGROUND

A randomized interventional phase 4 study in the Indian population confirmed the non-inferiority of the combination tenofovir/lamivudine/efavirenz (TLE)-400 to TLE600. The current manuscript describes in detail the safety profile and patient-reported safety outcomes obtained from the phase 4 study.

METHODS

This investigation was part of a phase 4 non-inferiority study with a blinded assessment, conducted across 17 sites in India. The duration of the study was 24 weeks. Safety endpoints assessed included all the adverse events (AEs) related to the study treatment (TLE400 and TLE600). The depression anxiety stress 21-item scale questionnaire and efavirenz-related symptom questionnaire were also used to measure depression, anxiety, stress, and patient experience.

RESULTS

A total of 68 patients (52.3%) reported 261 AEs and 87 patients (64.9%) reported 379 AEs related to study treatment in TLE400 group and TLE600 group respectively, P = .037. The reported AEs associated with central nervous system disorders were lower in the TLE400 group with 41 patients (31.5%) to 61 patients (45.5%) in the TLE600 group. The change from mean baseline value for depression anxiety stress 21-item scale at week 28 in TLE400 group and TLE600 group was -5.1 and -6.2 respectively. Similarly, the mean change from baseline score of efavirenz-related symptoms at week 28 in TLE400 group and TLE600 group were -5.1 and -4.1 respectively.

CONCLUSION

The low dose efavirenz (400 mg) in combination with tenofovir and lamivudine had a better safety and tolerability profile than the standard dose of efavirenz (600 mg) in combination with tenofovir and lamivudine. Thus, low dose efavirenz should be preferred over the standard dose.

Prolonged efavirenz exposure reduces peripheral oxytocin and vasopressin comparable to known drugs of addiction in male Sprague Dawley rats

Introduction

Several drugs of abuse (DOA) are capable of modulating neurohypophysial hormones, such as oxytocin (OT) and vasopressin (VP), potentially resulting in the development of psychological abnormalities, such as cognitive dysfunction, psychoses, and affective disorders. Efavirenz (EFV), widely used in Africa and globally to treat HIV, induces diverse neuropsychiatric side effects while its abuse has become a global concern. The actions of EFV may involve neurohypophysial system (NS) disruption like that of known DOA. This study investigated whether sub-chronic EFV exposure, at a previously-determined rewarding dose, alters peripheral OT and VP levels versus that of a control, ∆⁹-tetrahydrocannabinol (∆⁹-THC), methamphetamine (MA) and cocaine.

Materials and methods

To simulate the conditions under which reward-driven behavior had previously been established for EFV, male Sprague Dawley rats (n = 16/exposure) received intraperitoneal vehicle (control) or drug administration across an alternating sixteen-day dosing protocol. Control administration (saline/olive oil; 0.2 ml) occurred on odd-numbered and drug administration (EFV: 5 mg/kg, ∆⁹-THC: 0.75 mg/kg, MA: 1 mg/kg, or cocaine: 20 mg/kg) on even-numbered days followed by euthanasia, trunk blood collection and plasma extraction for neuropeptide assay. Effect of drug exposure on peripheral OT and VP levels was assessed versus controls and quantified using specific ELISA kits. Statistical significance was determined by Kruskal-Wallis ANOVA, with p < 0.05. Ethics approval: NWU-00291-17-A5.

Results

Delta-9-THC reduced OT and VP plasma levels (p < 0.0001, p = 0.0141; respectively), cocaine reduced plasma OT (p = 0.0023), while MA reduced plasma VP levels (p = 0.0001), all versus control. EFV reduced OT and VP plasma levels (p < 0.0001; OT and VP) versus control, and similar to ∆⁹-THC.

Conclusion

EFV markedly affects the NS in significantly reducing both plasma OT and VP equivalent to DOA. Importantly, EFV has distinct effects on peripheral OT and VP levels when assessed within the context of drug dependence. The data highlights a possible new mechanism underlying previously documented EFV-induced effects in rats, and whereby EFV may induce neuropsychiatric adverse effects clinically; also providing a deeper understanding of the suggested abuse-potential of EFV.

HIV-Associated Apathy/Depression and Neurocognitive Impairments Reflect Persistent Dopamine Deficits

Individuals living with human immunodeficiency virus type 1 (HIV-1) are often plagued by debilitating neurocognitive impairments and affective alterations;the pathophysiology underlying these deficits likely includes dopaminergic system dysfunction. The present review utilized four interrelated aims to critically examine the evidence for dopaminergic alterations following HIV-1 viral protein exposure. First, basal dopamine (DA) values are dependent upon both brain region andexperimental approach (i.e., high-performance liquid chromatography, microdialysis or fast-scan cyclic voltammetry). Second, neurochemical measurements overwhelmingly support decreased DA concentrations following chronic HIV-1 viral protein exposure. Neurocognitive impairments, including alterations in pre-attentive processes and attention, as well as apathetic behaviors, provide an additional line of evidence for dopaminergic deficits in HIV-1. Third, to date, there is no compelling evidence that combination antiretroviral therapy (cART), the primary treatment regimen for HIV-1 seropositive individuals, has any direct pharmacological action on the dopaminergic system. Fourth, the infection of microglia by HIV-1 viral proteins may mechanistically underlie the dopamine deficit observed following chronic HIV-1 viral protein exposure. An inclusive and critical evaluation of the literature, therefore, supports the fundamental conclusion that long-term HIV-1 viral protein exposure leads to a decreased dopaminergic state, which continues to persist despite the advent of cART. Thus, effective treatment of HIV-1-associated apathy/depression and neurocognitive impairments must focus on strategies for rectifying decreases in dopamine function.

Coronaridine congeners potentiate GABAA receptors and induce sedative activity in mice in a benzodiazepine-insensitive manner

To determine whether (+)-catharanthine induces sedative- or anxiolytic/anxiogenic-like activity in male mice, proper animal paradigms were used. The results showed that (+)-catharanthine induces sedative-like activity in the 63-72 mg/Kg dose range in a flumazenil-insensitive manner, but neither this effect nor anxiolytic/anxiogenic-like activity was observed at lower doses. To determine the underlying molecular mechanism of the sedative-like activity, electrophysiological and radioligand binding experiments were performed with (+)-catharanthine and (±)-18-methoxycoronaridine [(±)-18-MC] on GABA_A (GABA_ARs) and glycine receptors (GlyRs). Coronaridine congeners both activated and potentiated a variety of human (h) GABA_ARs, except hρ1. (+)-Catharanthine-induced potentiation followed this receptor selectivity (EC₅₀'s in μM): hα1β2 (4.6 ± 0.8) > hα2β2γ2 (12.6 ± 3.8) ~ hα1β2γ2 (14.4 ± 4.6) indicating that both α1 and α2 are equally important, whereas γ2 is not necessary. (+)-Catharanthine was >2-fold more potent and efficient than (±)-18-MC at hα1β2γ2. (+)-Catharanthine also potentiated, whereas (±)-18-MC inhibited, hα1 GlyRs with very low potency. Additional [³H]-flunitrazepam competition binding experiments using rat cerebellum membranes clearly demonstrated that these ligands do not bind to the benzodiazepine site. This is supported by the observed activity at hα1β2 (lacking the BDZ site) and similar effects between α1- and α2-containing GABA_ARs. Our study shows, for the first time, that (+)-catharanthine induced sedative-like effects in mice, and coronaridine congeners potentiated human α1β2γ2, α1β2, and hα2β2γ2, but not ρ1, GABA_ARs, both in a benzodiazepine-insensitive fashion, whereas only (+)-catharanthine slightly potentiated GlyRs.

Depression and Suicidal Ideation Among HIV-Infected Adults Receiving Efavirenz Versus Nevirapine in Uganda: A Prospective Cohort Study

BACKGROUND

Evidence regarding potential adverse neuropsychiatric effects of efavirenz is conflicting, and data from sub-Saharan Africa, where 70% of persons living with HIV (PLHIV) reside and efavirenz is used as first-line therapy, are limited.

OBJECTIVE

To estimate associations between efavirenz use and depression and suicidal ideation among PLHIV in Uganda.

DESIGN

Prospective observational cohort study. (ClinicalTrials.gov: NCT01596322).

SETTING

Mbarara, Uganda.

PARTICIPANTS

Adult PLHIV enrolled at the start of antiretroviral therapy (ART) and observed every 3 to 4 months from 2005 to 2015.

MEASUREMENTS

The exposure of interest was time-varying efavirenz use, defined as use during the 7 days and in 60 or more of the 90 days before a study visit, compared with nevirapine use. Self-reported outcomes were depression, defined as a mean score greater than 1.75 on the Hopkins Symptom Checklist depression subscale, and suicidal ideation. Multivariable-adjusted generalized estimating equations (GEE) logistic regression, Cox proportional hazards regression, and marginal structural models were fit to estimate the association between efavirenz use and the risk for depression and suicidal ideation.

RESULTS

694 participants (median age, 33 years; median pretreatment CD4+ count, 1.8 × 109 cells/L) contributed 1200 person-years of observation (460 person-years receiving efavirenz). No baseline differences in depression or suicidal ideation were found between patients ever exposed to efavirenz and those never exposed to efavirenz and receiving nevirapine (P > 0.80 for both). Of 305 participants ever-exposed to efavirenz, 61 (20.0%) and 19 (6.2%) had depression and suicidal ideation, respectively, on at least 1 follow-up visit, compared with 125 (32.1%) and 47 (12.1%) of the 389 who received nevirapine. In adjusted GEE models, efavirenz use was associated with decreased odds of depression compared with nevirapine use (adjusted odds ratio, 0.62 [95% CI, 0.40 to 0.96]) and was not significantly associated with suicidal ideation (adjusted odds ratio, 0.61 [CI, 0.30 to 1.25]). Time-to-event and marginal structural models yielded similar estimates.

LIMITATION

Nonrandom assignment to treatment and substantial differences between the efavirenz and nevirapine groups.

CONCLUSION

No evidence was found that use of efavirenz in first-line ART increased the risk for depression or suicidal ideation compared with nevirapine use among PLHIV in Uganda.

PRIMARY FUNDING SOURCE

National Institutes of Health.