Temazepam: a review of its pharmacological properties and therapeutic efficacy as an hypnotic

Pharmacotherapeutic management of insomnia and effects on sleep processes, neural plasticity, and brain systems modulating stress: A narrative review

Introduction

Insomnia is a stress-related sleep disorder, may favor a state of allostatic overload impairing brain neuroplasticity, stress immune and endocrine pathways, and may contribute to mental and physical disorders. In this framework, assessing and targeting insomnia is of importance.

Aim

Since maladaptive neuroplasticity and allostatic overload are hypothesized to be related to GABAergic alterations, compounds targeting GABA may play a key role. Accordingly, the aim of this review was to discuss the effect of GABAA receptor agonists, short-medium acting hypnotic benzodiazepines and the so called Z-drugs, at a molecular level.

Method

Literature searches were done according to PRISMA guidelines. Several combinations of terms were used such as “hypnotic benzodiazepines” or “brotizolam,” or “lormetazepam” or “temazepam” or “triazolam” or “zolpidem” or “zopiclone” or “zaleplon” or “eszopiclone” and “insomnia” and “effects on sleep” and “effect on brain plasticity” and “effect on stress system”. Given the complexity and heterogeneity of existing literature, we ended up with a narrative review.

Results

Among short-medium acting compounds, triazolam has been the most studied and may regulate the stress system at central and peripheral levels. Among Z-drugs eszopiclone may regulate the stress system. Some compounds may produce more “physiological” sleep such as brotizolam, triazolam, and eszopiclone and probably may not impair sleep processes and related neural plasticity. In particular, triazolam, eszopiclone, and zaleplon studied in vivo in animal models did not alter neuroplasticity.

Conclusion

Current models of insomnia may lead us to revise the way in which we use hypnotic compounds in clinical practice. Specifically, compounds should target sleep processes, the stress system, and sustain neural plasticity. In this framework, among the short/medium acting hypnotic benzodiazepines, triazolam has been the most studied compound while among the Z-drugs eszopiclone has demonstrated interesting effects. Both offer potential new insight for treating insomnia.

GABAA receptor positive allosteric modulators modify the abuse-related behavioral and neurochemical effects of methamphetamine in rhesus monkeys

GABA_A receptor positive allosteric modulators (GABA_A receptor modulators) are commonly used for the treatment of insomnia. Nevertheless, the effects of these compounds on psychostimulant-induced sleep impairment are poorly understood. Because GABA_A receptor modulators have been shown to decrease the abuse-related effects of psychostimulants, the aim of the present study was to evaluate the effects of temazepam (0.3, 1.0 or 3.0 mg/kg) and eszopiclone (0.3, 1.0 or 3.0 mg/kg), two GABA_A receptor modulators, on the behavioral neuropharmacology of methamphetamine in adult rhesus macaques (n = 5). Sleep-like measures and general daytime activity were evaluated with Actiwatch monitors. Methamphetamine self-administration (0.03 mg/kg/inf) was evaluated during morning sessions. Methamphetamine-induced dopamine overflow was assessed through in vivo microdialysis targeting the nucleus accumbens. Nighttime treatment with either temazepam or eszopiclone was ineffective in improving sleep-like measures disrupted by methamphetamine self-administration. Acute pretreatment with a low dose of temazepam before self-administration sessions increased methamphetamine self-administration without affecting normal daytime home-cage activity. At a high dose, acute temazepam pretreatment decreased methamphetamine self-administration and attenuated methamphetamine-induced increases in dopamine in the nucleus accumbens, without decreasing general daytime activity. Acute eszopiclone treatment exerted no effects on methamphetamine intake or drug-induced increases in dopamine. Our study suggests that treatments based on GABA_A receptor modulators are not effective for the treatment of sleep disruption in the context of psychostimulant use. In addition, distinct GABA_A receptor modulators differentially modulated the abuse-related effects of methamphetamine, with acute treatment with the high efficacy GABA_A receptor modulator temazepam decreasing the behavioral and neurochemical effects of methamphetamine.

Classics in chemical neuroscience: diazepam (valium)

Diazepam (Valium) is among the most successful drugs from the onset of the psychopharmacological revolution that began during the 1950s. Efficacious in treating a wide-spectrum of CNS disorders, including anxiety and epilepsy, it set the standard for pharmacotherapy in terms of potency, onset of action, and safety. In this Review, the legacy of diazepam to chemical neuroscience will be considered along with its synthesis, pharmacology, drug metabolism, adverse events and dependence, clinical use, and regulatory issues.

Impact of benzodiazepines on posaconazole serum concentrations. A population-based pharmacokinetic study on drug interaction

OBJECTIVES

Posaconazole is broadly used for antifungal prophylaxis and therapy. Current data suggest a concentration-dependent effect. Unlike other triazoles, cytochrome P450 is not a relevant route of biotransformation for posaconazole but glucuronidation, which might lead to a different spectrum of drug interactions. For benzodiazepines, the major metabolic pathway involves oxidation, but some, including lorazepam and temazepam, undergo conjugation to glucuronic acid.

RESEARCH DESIGN AND METHODS

Since 2006 serum levels of posaconazole are determined regularly in all hospitalized patients with intake of this triazole. Here we investigate posaconazole concentration at steady state in relation to the concomitant medication of benzodiazepines.

RESULTS

While similar posaconazole concentrations were determined in samples obtained from patients receiving temazepam when compared to samples without any benzodiazepine, a relevant reduction of posaconazole concentration could be observed in patients with concomitant intake of lorazepam. This difference in posaconazole concentration with or without concomittant intake of lorazepam, was consistently significant for analyses of all samples (median 336 ng/ml vs. 585 ng/ml, p 0.001), for the average concentrations (569 ng/ml vs. 276 ng/ml, p 0.039), and for patients receiving a total daily dose of 800 mg posaconazole (292 ng/ml vs. 537 ng/ml, p 0.003). There was also a similar, but not significant trend for patients with a prophylactic dosage of 200 mg posaconazole three times daily (689 ng/ml vs. 512 ng/ml, p 0.186).

CONCLUSIONS

In this retrospective study, analyzing blood samples from daily clinical practice of patients in various clinical settings and with different indications for antifungal therapy, concomitant medication of lorazepam was associated with decreased posaconazole concentrations. Therefore, lorazepam but not temazepam might induce posaconazole clearance by glucuronidation.

Postmortem toxicology of drugs of abuse

Conducting toxicology on post-mortem specimens provides a number of very significant challenges to the scientist. The range of additional specimens include tissues such as decomposing blood and other tissues, hair, muscle, fat, lung, and even larvae feeding on the host require special techniques to isolate a foreign substance and allow detection without interference from the matrix. A number of drugs of abuse are unstable in the post-mortem environment that requires careful consideration when trying to interpret their significance. Heroin, morphine glucuronides, cocaine and the benzodiazepines are particularly prone to degradation. Moreover, redistributive process can significantly alter the concentration of drugs, particularly those with a higher tissue concentration than the surrounding blood. The designer amphetamines, methadone and other potent opioids will increase their concentration in blood post-mortem. These processes together with the development of tolerance means that no concentration of a drug of abuse can be interpreted in isolation without a thorough examination of the relevant circumstances and after the conduct of a post-mortem to eliminate or corroborate relevant factors that could impact on the drug concentration and the possible effect of a substance on the body. This article reviews particular toxicological issues associated with the more common drugs of abuse such as the amphetamines, cannabinoids, cocaine, opioids and the benzodiazepines.

Effects of after-midnight intake of zolpidem and temazepam on driving ability in women with non-organic insomnia

BACKGROUND

Occasionally, insomniac patients may take a sleeping pill after midnight. This may have consequences on their ability to drive a car and result in an increased risk of car accidents.

METHODS

This double-blind, randomized, placebo-controlled, three-treatment three-period cross-over study investigated the effects of two frequently prescribed hypnotics of different classes in a real life condition on driving performance and psychomotor skills in insomniac women. Single doses of zolpidem 10 mg (Z), temazepam 20 mg (T) or placebo (P) were administered at 2:00 a.m. to 19 women aged 35-60 years in three treatment periods separated by wash-out periods of 3-14 days. After polysomnography at baseline and each treatment night, patients underwent, 5.5 h after drug intake at 7:30 a.m. on the next morning, a STISIM driving simulator test, and a subsequent neuropsychological test (FePsy).

RESULTS

Eighteen insomniac women were included in the analysis (mean age 50 years, mean weight 69 kg, mean BMI 25.6 kg/m2). There were no differences between treatments for the primary outcome measure (mean time to collision; baseline: 0.120 s, P: 0.124, T: 0.118, Z: 0.124; P> or =0.12 for all pairwise comparisons). No differences were recorded for speed deviation and reaction time to tasks for the verum treatments, however, lane position deviation was greater after administration of zolpidem in comparison to both placebo and temazepam (P=0.025 and 0.05, respectively). There were no differences between treatments in the FePsy test. Both medications were well tolerated.

CONCLUSIONS

5.5 h after drug administration there were no major differences in psychomotor performances between both zolpidem and temazepam compared to placebo, which indicates the absence of significant residual effects at that time. However, certain patients were more susceptible than others to the drug effects (two patients with high number of collisions). This underlines the necessity to strongly advocate against the late intake of hypnotics if patients intend to drive a car early the next morning.

Problems with sleep: what should the doctor do?

Complaints of poor sleep are frequent. The physician's assessment should seek to diagnose the social, medical, and psychiatric etiologies of insomnia and to treat the identified causative conditions. Management must match the specific pathology and type of sleep problem.

Association of benzodiazepine injection with the prescription of temazepam capsules

Temazepam capsules have become a popular choice for benzodiazepine injection by injecting drug users, and serious vascular and tissue damage leading to ulcers and gangrene can result. We compared the self-reported benzodiazepine injecting behaviour of 91 heroin users with their Pharmaceutical Benefits Schedule (PBS) records for the preceding 5 years. We found that individuals prescribed PBS temazepam capsules were more likely to report injecting benzodiazepines than individuals who had either not been prescribed PBS temazepam capsules or had been prescribed PBS temazepam tablets. These results provide empirical support for the argument to limit the prescription and supply of temazepam capsules in Australia.

Adverse effects of temazepam in older adults with chronic insomnia

BACKGROUND

Benzodiazepine-hypnotics are frequently used for treating insomnia in older adults; however, there is little information about adverse effects associated with their usage over several weeks, particularly in this segment of the population.

OBJECTIVE

This study reports on the incidence of adverse effects of temazepam in older adults with chronic insomnia and examines whether the addition of cognitive-behaviour therapy (CBT) is associated with less drug used and fewer adverse effects.

METHOD

Sixty patients with chronic and primary insomnia were randomized to temazepam (n = 20), placebo (n = 20) or temazepam plus CBT (n = 20). Data from the physicians' weekly assessments and patients' sleep diaries were used to evaluate adverse effects, the dose (7.5-30 mg) at which they occurred, and drug use patterns over the 8-week course of treatment.

RESULTS

The incidence of adverse effects was infrequent, as shown by the low percentages of complaints reported by patients in the temazepam (7.8%), placebo (10.8%) and combination groups (8.3%). The severity of adverse events was mild and decreased over the course of treatment. The maximum dose was reached by 10 patients receiving temazepam, 14 placebo and 7 in the combined treatment. The average nightly dosage used was 20 mg for both the temazepam and placebo groups and 16 mg for the combined condition. Patients receiving temazepam plus CBT used less drugs, with approximately the same incidence of adverse effects.

CONCLUSION

Temazepam is a safe hypnotic for use by older adults over an 8-week treatment period. There are few adverse effects and behavioural tolerance to those effects develop over time. The addition of cognitive-behavioural intervention reduced both the amount of medication used and the incidence of adverse effects, with comparable sleep improvements.

Analysis of a sleep-dependent neuronal feedback loop: the slow-wave microcontinuity of the EEG

Increasing depth of sleep corresponds to an increasing gain in the neuronal feedback loops that generate the low-frequency (slow-wave) electroencephalogram (EEG). We derived the maximum-likelihood estimator of the feedback gain and applied it to quantify sleep depth. The estimator computes the fraction (0%-100%) of the current slow wave which continues in the near-future (0.02 s later) EEG. Therefore, this percentage was dubbed slow-wave microcontinuity (SW%). It is not affected by anatomical parameters such as skull thickness, which can considerably bias the commonly used slow-wave power (SWP). In our study, both of the estimators SW% and SWP were monitored throughout two nights in 22 subjects. Each subject took temazepam (a benzodiazepine) on one of the two nights. Both estimators detected the effects of age, temazepam, and time of night on sleep. Females were found to have twice the SWP of males, but no gender effect on SW% was found. This confirms earlier reports that gender affects SWP but not sleep depth. Subjectively assessed differences in sleep quality between the nights were correlated to differences in SW%, not in SWP. These results demonstrate that slow-wave microcontinuity, being based on a physiological model of sleep, reflects sleep depth more closely than SWP does.

Eltanolone for induction of anaesthesia in the surgical patient. A comparison of dose requirements in young and elderly patients

BACKGROUND

The relative potency of the steroid anaesthetic agent eltanolone has been compared with respect to induction of anaesthesia in ASA I and II young (18-40 years) and elderly (> 65 years) patients.

METHOD

113 temazepam premedicated patients (60 elderly) were evaluated in an open randomised study. They were allocated to receive doses between 0.05 and 0.75 mg/kg given i.v. over 30 s. The first 33 patients formed a pilot phase; the formal study comprised 80 patients. The primary efficacy variable was loss of verbal contact within 120 s and an effect lasting more than 4 min. All patients breathed 100% oxygen throughout the study period. Safety data (heart rate, blood pressure, respiratory apnoea, involuntary movements, hypertonus and other adverse effects) were noted.

RESULTS

Anaesthesia was adequately induced in 12/40 elderly and 7/40 young patients. The lowest effective induction dose was 0.2 mg/kg in elderly and 0.3 mg/kg in young patients. This gave a relative potency of 0.28 (95% CI 0.12-0.52; P = 0.0039). The cardiovascular effects associated with induction were small; other side-effects included involuntary movement and hypertonus, and respiratory upsets (apnoea, hiccups and coughing).

CONCLUSION

The effective induction dose of eltanolone was significantly lower in the elderly patients; but the drug safety profile was similar in both age groups of patients.

Sudden death and benzodiazepines

A study of 16 deaths associated with toxic concentrations of benzodiazepines during the period of 5 years leading up to July 1994 is presented. Cases where other drugs, including ethanol, had contributed to the death were excluded. All cases were subject to a full macroscopic and microscopic examination by pathologists, and all cases were subject to a full toxicological work-up. Preexisting natural disease was a feature of 11 cases. In the remaining five cases, death was caused solely by benzodiazepines. There were 14 suicides. Nitrazepam and temazepam were the most prevalent drugs detected, followed by oxazepam and flunitrazepam. Minimum toxic femoral blood concentrations of 7-aminonitrazepam, 7-aminoflunitrazepam, and oxazepam were estimated as 0.5, 0.2, and 2 mg/L, respectively. Relating these deaths to prescription rates in Victoria suggest that flunitrazepam may be inherently more toxic if misused than other benzodiazepines currently available on the Australian market.

A clinical trial comparing two doses of oral temazepam for sedation of paediatric dental patients

A study was carried out to compare the effectiveness of two doses of temazepam elixir for the behaviour management of paediatric dental patients. Twenty-two children aged 2-5 years (mean 4.06 years), classified as ASA Class I and II (American Society of Anesthesiologists Classification), were assigned to receive either 0.3 or 0.5 mg/kg temazepam elixir in a double-blind randomized cross-over study. All treatment sessions were videotaped and rated independently by three paediatric dentists for the degree of crying, movement, sleep and overall behaviour at 15-minute intervals while being treated. The results showed no statistically significant differences between the two doses.

Effect of temazepam on blood pressure regulation in healthy elderly subjects

1. Blood pressure regulation was studied in 12 healthy elderly subjects after double-blind randomised administration of placebo, 15 mg and 30 mg temazepam at 10.00 h and 22.00 h. 2. Supine and standing heart rate and blood pressure were measured after daytime administration and supine measurements were obtained during sleep. 3. Temazepam caused a fall in systolic blood pressure and an increase in heart rate after morning administration. These changes were greater in the standing position and were dose-dependent; for standing blood pressure and heart rate 1 h after administration there was a 7 mm Hg fall and 6 beats min-1 increase after 15 mg temazepam and a 10 mm Hg fall and 8 beats min-1 increase after 30 mg temazepam. Temazepam magnified the fall in systolic blood pressure and increase in heart rate that occurred with standing. Temazepam enhanced the fall in systolic blood pressure that occurred during sleep (mean +/- s.d.; placebo: -23 +/- 10 mm Hg, 15 mg temazepam: -31 +/- 13 mm Hg, 30 mg temazepam: -36 +/- 14 mm Hg). 4. These changes in blood pressure regulation caused by temazepam may have clinical importance in some elderly individuals.

Evaluation of temazepam and diphenhydramine as hypnotics in a nursing-home population

Seventeen nursing home residents with sleeping problems were enrolled in a randomized, double-blind, crossover trial of temazepam 15 mg, diphenhydramine (DPH) 50 mg, and placebo. Each drug was given for five consecutive nights with a 72-hour washout period between drugs. Subjects were assessed three times weekly with tests of psychomotor and cognitive function and four times weekly with observer sleep diaries and morning sleep questionnaires. Three subjects failed to complete the study. By report of the subjects, DPH resulted in shorter sleep latency than did placebo (t = 2.77, p less than 0.05). On the fifth night, use of DPH was associated with longer duration of sleep than temazepam (t = 2.88, p less than 0.05). No significant difference in tests of neurologic function was noted although, compared with placebo, subjects performed more poorly on seven of eight tests while taking temazepam and five of eight tests while taking DPH. Several instances of daytime hypersomnolence were noted in subjects taking temazepam and DPH, but none in subjects given placebo.

Clinical trial design: the neglected problem of asymmetrical transfer in cross-over trials

The paper illustrates drawbacks of the popular cross-over design in clinical trials in psychiatry where treatment effects become distorted by, and confounded with, the effects of their order of administration. It is argued that research workers should analyse data from cross-over trials for asymmetries due to order of treatment and seriously doubt the reliability of data if such effects are found. The problem is avoided by the use of separate-groups designs.

Temazepam (Restoril, Sandoz Pharmaceuticals)

Temazepam is a benzodiazepine derivative indicated for the treatment of insomnia. Pharmacokinetic studies of the hard capsule formulation indicate that the mean time to peak is 2.99 hours and the mean elimination half-life is 14.7 hours. Sleep laboratory studies have demonstrated improvements in all sleep parameters except sleep onset latency. Clinically, patients report improvements in all sleep parameters including sleep onset latency. The efficacy of temazepam compares favorably with barbiturates, glutethimide, nitrazepam, lorazepam, oxazepam, and flurazepam. It has not been compared with diazepam in the clinical setting. Side effects include drowsiness, dizziness, and lethargy. The incidence of hangover effects from 15- and 30-mg doses is relatively low. Temazepam has no proven advantages over other benzodiazepine hypnotics. The major issues that need further clarification include temazepam's sleep induction properties and the relative incidence of hangover and rebound insomnia when compared with longer-acting benzodiazepines.