Background: Insomnia is common in patients with major depressive disorder. Although antidepressants improve mood, insomnia often persists as a result of physiological hyperarousal. The orexin-2 receptor is increasingly being recognized as a new target for the treatment of persistent insomnia in major depressive disorder . Aim: This exploratory study investigated the effects of seltorexant on objective sleep parameters and subjective depressive symptoms in antidepressant treated major depressive disorder patients with persistent insomnia. Methods: Twenty male and female patients received a single dose of 10, 20, 40 mg seltorexant and placebo with a washout period of seven days in a double-blind four-way crossover study. Effects on latency to persistent sleep, total sleep time and sleep efficiency were assessed with polysomnography. Subjective changes in mood were explored by the Quick Inventory of Depressive Symptomatology Self-Report. Safety was recorded and suicidal ideation and behavior were assessed with the Columbia Suicide Severity Rating Scale. Results: Latency to persistent sleep was significantly shorter for all doses of seltorexant compared to placebo. Placebo least square mean was 61.05 min with least square mean ratios treatment/placebo (80% confidence interval) of 0.32 (0.24–0.44), 0.15 (0.11–0.2) and 0.17 (0.12–0.23) 19.69, 9.2, 10.15 for 10, 20 and 40 mg seltorexant respectively, (all p<0.001). Total sleep time was significantly longer for all doses of seltorexant compared to placebo. Sleep efficiency was significantly improved. The Quick Inventory of Depressive Symptomatology Self-Report demonstrated a trend to mood-improvement for the 40 mg group. Conclusions: Seltorexant showed a statistically significant, dose-dependent decrease in latency to persistent sleep, and increase in total sleep time and sleep efficiency combined with a tendency toward subjectively improved mood.
The aim was to investigate the ability of a battery of pain models to detect analgesic properties of commonly used analgesics in healthy subjects.The battery consisted of tests eliciting electrical, mechanical and thermal (contact heat and cold pressor)-pain and included a UVB model, the thermal grill illusion and a paradigm of conditioned pain modulation. Subjects were administered fentanyl 3 μg kg-1 , phenytoin 300 mg, (S)-ketamine 10 mg and placebo (part I), or imipramine 100 mg, pregabalin 300 mg, ibuprofen 600 mg and placebo (part II). Pain measurements were performed at baseline and up to 10 h post-dose. Endpoints were analysed using a mixed model analysis of variance.Sixteen subjects (8 female) completed each part. The pain tolerance threshold (PTT) for electrical stimulation was increased (all P < 0.05) compared to placebo for (S)-ketamine (+10.1%), phenytoin (+8.5%) and pregabalin (+10.8%). The PTT for mechanical pain was increased by pregabalin (+14.1%). The cold pressor PTT was increased by fentanyl (+17.1%) and pregabalin (+46.4%). Normal skin heat pain detection threshold was increased by (S)-ketamine (+3.3%), fentanyl (+2.8%) and pregabalin (+4.1%). UVB treated skin pain detection threshold was increased by fentanyl (+2.6%) and ibuprofen (+4.0%). No differences in conditioned pain modulation were observed.This study shows that these pain models are able to detect changes in pain thresholds after administration of different classes of analgesics in healthy subjects. The analgesic compounds all showed a unique profile in their effects on the pain tasks administered.
Rationale: Assessment of the effects of medicines on the risks of car driving must be derived from laboratory tests, simulated driving or real on-road driving tests. Relevance of tests is determined by their sensitivity and predictive ability for the probability of accidents or damage. This cannot be determined directly, but methods should be able to at least detect the effects of a positive control in dosage known to be clearly associated with increased risk. Objectives: A driving simulator was evaluated in comparison with a battery of validated tests of CNS performance, the NeuroCart®. Alcohol in a concentration exactly at the legal limit (0.5 g L −1 ) and well above (1.0 g L −1 ) as well as alprazolam (1 mg) was used as positive control. Methods: This was a randomised, cross-over study using a double dummy blinded design in 24 healthy study subjects (12 M, 12 F) aged 20–43 years. Alcohol was infused intravenously using a validated clamping protocol to obtain concentrations of 0.5 g L −1 and on another occasion 1.0 g L −1 . Alprazolam was given orally. Driving tests and lab tests were done at regular time intervals during a study day. Results: Alprazolam and alcohol significantly affected the main parameters of driving in the simulator and affected scores of safe driving and alprazolam increased the odds ratio of a virtual crash. Several laboratory measurements of psychomotor performance were affected by the reference substances as expected and correlated significantly with the driving performance Conclusions: The driving simulator can detect effects of reference substances at levels that are known to negatively affect driving.
Since glycinergic neurotransmission plays an important inhibitory role in the processing of sensory and motor information, intrathecal glycine (ITG) administration may be a potential therapy for both pain and movement disorders in patients with complex regional pain syndrome (CRPS). Aims of the current study, which is the first report on ITG in humans, were to evaluate its safety and efficacy. ITG treatment during 4 weeks was studied in CRPS patients with dystonia in the period before they received intrathecal baclofen treatment. Twenty patients were assessed and after exclusion of one patient, the remaining 19 patients were randomized in a double-blind placebo-controlled crossover study. Safety was assessed by clinical evaluation, blood examinations and electrocardiograms. Efficacy measures involved pain (numeric rating scale, McGill pain questionnaire), movement disorders (Burke-Fahn-Marsden dystonia rating scale, unified myoclonus rating scale, tremor research group rating scale), activity (Radboud skills questionnaire, walking ability questionnaire), and a clinical global impression (CGI) and patient's global impression score (PGI). Treatment-emergent adverse events were generally mild to moderate and not different from placebo treatment. During ITG treatment growth hormone levels were slightly increased. Although there was a trend to worsening on the CGI and PGI during ITG treatment, there were no significant differences between ITG and placebo treatment in any of the outcomes. ITG given over 4 weeks was ineffective for pain or dystonia in CRPS. Although no serious adverse events occurred, further studies are required to rule out potential neurotoxicity of ITG.
The objectives of this study were to investigate the multiple-dose tolerability, safety, pharmacokinetics, and pharmacodynamics of the dual orexin receptor antagonist almorexant. Healthy subjects received daily doses of almorexant (100, 200, 400 or 1000 mg) or placebo in the morning for four days followed by two days with evening administration (Days 5–6). Each dose level was investigated in a new group of 10 subjects (eight active, two placebo, 1:1 sex). Dose-dependent increases in frequency and intensity were observed for somnolence and other adverse events. Pharmacokinetics at steady state showed rapid absorption, low concentrations eight hours post-dose, and minimal accumulation. Following evening, administration absorption was delayed and C max decreased. Almorexant at 400 and 1000 mg administered in the morning reduced vigilance, alertness, visuomotor coordination, and motor coordination assessed in a psychometric test battery. Polysomnography recordings following evening administration showed a trend towards shorter latency to sleep stages 3 and 4, and shorter latency to, and longer time in, rapid-eye-movement sleep at higher doses when compared to placebo. Whether these findings in healthy subjects translate into relevant sleep-enabling effects in insomnia patients needs to be investigated in future studies.
Sleep disorders are common in the elderly population. Orexin receptor antagonism has been proposed as a new sleep-enabling approach to treat insomnia. The tolerability, pharmacokinetics, and pharmacodynamics of ascending single doses of almorexant, a dual orexin receptor antagonist, were investigated in healthy elderly male and female subjects. In this double-blind, placebo- and active-controlled study, each dose (100, 200, and 400 mg) was investigated in a separate group of 12 subjects (almorexant, placebo, and zolpidem 10 mg in an 8:2:2 ratio). Morning doses of almorexant were well tolerated. As expected for sleep-enabling compounds, somnolence and fatigue were frequently reported. Other adverse events included headache and nausea. Muscular weakness was reported at a higher incidence only with the highest almorexant dose. The pharmacokinetic profile of almorexant was characterized by a median time to the maximum concentration of 1.5 hours, quick disposition with a distribution half-life of 1.6 hours, and rapidly decreasing concentrations to approximately 20% of the maximum concentration over 8 hours, with a terminal half-life of 32 hours. Objective pharmacodynamic measures showed decreases in saccadic peak velocity and adaptive tracking performance and increases in body sway with the 400-mg dose of almorexant. Subjective assessments revealed a dose-dependent decrease in alertness. Almorexant had no effects on mood, calmness, subjective internal and external perception, and feeling high. These findings provide a solid basis to study the effects of almorexant in elderly patients with insomnia.
Background: Preclinical research suggests that cannabidiol (CBD) may have therapeutic potential in pathological anxiety. Dosing guidelines to inform future human studies are however lacking. Aim: We aimed to predict the therapeutic window for anxiety-reducing effects of CBD in humans based on preclinical models. Methods: We conducted two systematic searches in PubMed and Embase up to August 2021, into pharmacokinetic (PK) and pharmacodynamic (PD) data of systemic CBD exposure in humans and animals, which includes anxiety-reducing and potential side effects. Risk of bias was assessed with SYRCLE’s RoB tool and Cochrane RoB 2.0. A control group was an inclusion criterion in outcome studies. In human outcome studies, randomisation was required. We excluded studies that co-administered other substances. We used the IB-de-risk tool for a translational integration of outcomes. Results: We synthesised data from 87 studies. For most observations (70.3%), CBD had no effect on anxiety outcomes. There was no identifiable relation between anxiety outcomes and drug levels across species. In all species (humans, mice, rats), anxiety-reducing effects seemed to be clustered in certain concentration ranges, which differed between species. Discussion: A straightforward dosing recommendation was not possible, given variable concentration–effect relations across species, and no consistent linear effect of CBD on anxiety reduction. Currently, these results raise questions about the broad use as a drug for anxiety. Meta-analytic studies are needed to quantitatively investigate drug efficacy, including aspects of anxiety symptomatology. Acute and (sub)chronic dosing studies with integrated PK and PD outcomes are required for substantiated dose recommendations.
In patients with Huntington's disease (HD), instrumental daily activities such as working and driving become affected at a relatively young age. For most patients, the decision to quit driving is difficult and affects their independence and social activities.
Aims
To investigate if differences in driving performance between HD gene carriers and healthy individuals can be detected with a driving simulator. Furthermore, we wanted to determine which cognitive and motor symptoms contribute to driving performance in HD.
Methods
We included 58 HD gene carriers (28 premanifest HD, 30 manifest HD) and 29 controls in this cross-sectional study. All participants were active drivers and underwent neuropsychological, motor, and psychiatric evaluations. A driving simulator, including an urban and motorway scenario, was used to assess driving performance.
Results
Manifest HD drove slower compared to controls and premanifest HD when speed limits increased (80 and 100 km/h) and they had a less steady speed compared to premanifest HD on the motorway and in a 30 km/h zone. Manifest HD also had a larger standard deviation of the lateral position (i.e., more weaving of the car) compared to controls and premanifest HD on the motorway. Postural instability and slower speed of processing were predictors of the driving simulator outcome measures. There were no significant differences between premanifest HD and controls.
Conclusions
Manifest HD drive more cautious in a driving simulator when speed limits increase compared to premanifest HD and controls and they have less vehicle control on the motorway. Increased postural instability and slower speed of processing are predictive of worse driving simulator performance in manifest HD. This might assist clinicians in their referral for an official on-road driving test. More studies are necessary to determine if a driving simulator can be used to monitor longitudinal changes in fitness to drive.
