Pharmacokinetics of brotizolam in the elderly

Safety of brotizolam in hospitalized patients

PURPOSE

The objective of this study was to evaluate the safety of brotizolam in hospitalized patients.

METHODS

A single-center, comparative retrospective cohort analysis of patients hospitalized in internal medicine wards. Patients treated with brotizolam were compared to patients not treated with any benzodiazepines during hospitalization. Primary outcome was any of the following safety events: mechanical ventilation, delirium, and falls.

RESULTS

Six hundred patients were included after exclusion in the final analysis; 300 treated with brotizolam (treatment) and 300 not treated with any benzodiazepines (comparator). The brotizolam-treated patients were older with more comorbidities and psychotropic medications. After adjustment using multivariate logistic regression analysis with propensity score, the primary outcomes occurred at significantly higher rates in treated patients than in untreated patients (17 vs. 2 events; OR = 7.33). Any psychotropic medication administered during hospitalization was found by logistic regression to be the main independent risk factor for the studied safety outcomes while age, comorbidities, and the cause of hospitalization were not.

CONCLUSIONS

Treatment with brotizolam during hospitalization in internal medicine wards is linked to a higher risk of respiratory deterioration, delirium, and falls. Use of psychotropic medications during hospitalization is the main independent risk factor of safety outcomes. Further research is needed to fully evaluate the risks and benefits of sleep induction medications in hospitals.

Analysis of the variability of the pharmacokinetics of multiple drugs in young adult and elderly subjects and its implications for acceptable daily exposures and cleaning validation limits

The elderly constitute a significant, potentially sensitive, subpopulation within the general population, which must be taken into account when performing risk assessments including determining an acceptable daily exposure (ADE) for the purpose of a cleaning validation. Known differences in the pharmacokinetics of drugs between young adults (who are typically the subjects recruited into clinical trials) and the elderly are potential contributors affecting the interindividual uncertainty factor (UF_H) component of the ADE calculation. The UF_H values were calculated for 206 drugs for young adult and elderly groups separately and combined (with the elderly assumed to be a sensitive subpopulation) from published studies where the pharmacokinetics of the young adult and elderly groups were directly compared. Based on the analysis presented here, it is recommended to use a default UF_H value of 10 for worker populations (which are assumed to be approximately equivalent to the young adult groups) where no supporting pharmacokinetic data exist, while it is recommended to use a default UF_H value of 15 for the general population, to take the elderly into consideration when calculating ADE values. The underlying reasons for the large differences between the exposures in the young adult and elderly subjects for the 10 compounds which show the greatest separation are different in almost every case, involving the OCT2 transporter, glucuronidation, hydrolysis, CYP1A2, CYP2A6, CYP2C19, CYP2D6, CYP3A4 or CYP3A5. Therefore, there is no consistent underlying mechanism which appears responsible for the largest differences in pharmacokinetic parameters between young adult and elderly subjects.

Variables influencing patient satisfaction for hypnotics: difference between zolpidem and brotizolam

WHAT IS KNOWN AND OBJECTIVE

The pharmacokinetics of zolpidem and brotizolam is affected by gender and age, that is, increased clearance in males taking zolpidem and younger subjects taking brotizolam. The purpose of this study was to determine the variables including gender and age influencing patient satisfaction for hypnotics, zolpidem and brotizolam.

METHODS

The study included 329 patients who were treated with zolpidem (n = 172) and brotizolam (n = 157) for insomnia. Patients were interviewed to evaluate individual satisfaction and drug efficacy. The factors associated with dissatisfaction of zolpidem and brotizolam were identified using multiple logistic analysis.

RESULTS AND DISCUSSION

Of the participating patients, 40 (23%) and 41 (26%) complained of dissatisfaction with zolpidem and brotizolam, respectively. An insufficient amount of sleep (<6 h) and the number of awakenings were common factors cited for dissatisfaction for both drugs. Males were found to report a higher rate of dissatisfaction for zolpidem, whereas patients younger than 65 years and those receiving corticosteroid therapy reported a higher rate of dissatisfaction with brotizolam.

WHAT IS NEW AND CONCLUSION

These results suggested that patient satisfaction was different between zolpidem and brotizolam in terms of gender for zolpidem and age and corticosteroid co-administration for brotizolam, which could be used to help choose a better drug among the two in patients with insomnia.

Hypnotic drugs, psychomotor performance and ageing

This review examines studies, reported since 1976, in which the residual effects of hypnotic drugs on psychomotor performance have been evaluated in older people. The 33 studies involved a total of 934 subjects (aged 60-96 y), evaluated 21 different products, utilized 26 test procedures, and reported 169 drug versus placebo (or drug versus drug) comparisons, of which 42 were associated with significant residual impairment. While performance decrements were more associated with longer half-life drugs, repeated dosing, and frailty, these characteristics were often unreliable in predicting outcome. Significant improvements in performance were rare, and usually consistent with practice effects. While this literature provides a useful basis for clinical caution, it is not characterized by experimental rigour, and provides little or no empirical basis for predicting those real-life skills most likely to be affected. Issues of subject selection, experimental design, testing strategies, and data analysis need to be addressed if the risks and benefits of hypnotic drug use in later life are to be more clearly understood.

Clinical pharmacokinetics of anxiolytics and hypnotics in the elderly. Therapeutic considerations (Part II)

Part I of this article, which appeared in the previous issue of the Journal, discussed the scope of and scientific basis for special pharmacokinetic studies of anxiolytic and hypnotic drugs in the elderly, and examined the methodology and results of such studies and the prediction of pharmacokinetic changes. In Part II the authors continue their review, focusing on age-related pharmacodynamic changes in the effects of these drugs, the attempts to correlate pharmacokinetic with pharmacodynamic findings, and the clinical applications of these data.

Hepatic drug metabolism and aging

Although there is considerable variation in the effect of age on drug biotransformation, the metabolism of many drugs is impaired in the elderly. Age-related physiological changes, such as a reduction in liver mass, hepatic metabolising enzyme activity, liver blood flow and alterations in plasma drug binding may account for the decreased elimination of some metabolised drugs in the elderly. It is difficult, however, to separate an effect of aging from a background of marked variation in the rate of metabolism due to factors such as individual metabolic phenotype, environmental influences, concomitant disease states and drug intake. The prevailing data suggest that initial doses of metabolised drugs should be reduced in older patients and then modified according to the clinical response. In most studies the elderly appear as responsive as young individuals to the effects of compounds which induce or inhibit the activity of cytochrome P450 isozymes. Concurrent use of other agents, which induce or inhibit drug metabolism, mandates dose adjustment as in younger patients. Many questions remain unanswered. For instance, limitations of in vitro studies prevent any firm conclusion about changes in hepatic drug metabolising enzyme activity in the elderly. With aging, some pathways of drug metabolism may be selectively affected, but this has not been adequately scrutinised. The possibility that metabolism of stereoisomers may be altered in the elderly has not been adequately tested. The effect of aging on the distribution of polymorphic drug metabolism phenotypes is still not established, despite potential implications for disease susceptibility and survival advantage.

Neurochemical and pharmacokinetic correlates of the clinical action of benzodiazepine hypnotic drugs

Benzodiazepine derivatives are presumed to exert their pharmacologic activity via interaction with specific molecular recognition sites, termed benzodiazepine receptors, within the brain. The various benzodiazepines used in clinical practice differ considerably in their intrinsic receptor affinity, but the qualitative character of the drug-receptor interaction is similar or identical among this class of drugs. All benzodiazepines are lipophilic (lipid-soluble) substances that relatively rapidly cross the blood-brain barrier and equilibrate with brain tissue. After equilibrium is attained, a constant brain:plasma ratio is maintained, such that plasma concentrations proportionately reflect concentrations of drug in brain. Brain concentrations are proportional to the extent of receptor occupancy, which in turn determines the acute behavioral effect. Clinical differences among benzodiazepines largely reflect differences in pharmacokinetic properties. The onset of action after single oral doses reflects the rate of absorption from the gastrointestinal tract, whereas the duration of action is determined by the rate and extent of drug distribution to peripheral tissues, as well as by the rate of elimination and clearance. During multiple dosage, long half-life drugs accumulate, with the concurrent possibility of daytime sedation. However, a benefit of long half-life drugs is that rebound insomnia on abrupt termination is unlikely. Short half-life drugs accumulate minimally and have a lower likelihood of producing daytime sedation. However, they may be more likely to produce rebound insomnia on abrupt discontinuation.

Alprazolam in the elderly: pharmacokinetics and pharmacodynamics during multiple dosing

Previous studies have suggested that elderly men eliminate alprazolam more slowly than young adults. This study in the elderly was designed to determine whether a change in pharmacokinetics influences the response to alprazolam during multiple dose regimens. In addition, the study was designed to determine alprazolam pharmacokinetics and the degree to which its hydroxymetabolites accumulate, the degree of psychomotor impairment, and whether tolerance to impairment and sedation develops during three different multiple dose regimens. Twenty-six subjects completed this study. The subjects were randomized into one of three treatment groups: 0.25 mg q8h, 0.5 mg q8h, and 2 mg q12h. Subjects remained in the clinic for 8 days (day -2-day 5). Day 0 was used as a drug free testing day to establish baseline scores for sedation, digit symbol substitution (DSS), card sorting (CS) tasks, and two computer tests. Subjects received the drug according to schedule on days 1 through 4, with day 5 as the washout day. Blood samples were assayed for alprazolam, alpha-hydroxyalprazolam and 4-hydroxyalprazolam. Alpha-hydroxyalprazolam concentrations were below assay detection limits in all subjects in the 0.25 and 0.5 mg q8h groups and less than or equal to 2.6 ng/ml in the 2 mg q12h group. When detectable, 4-hydroxyalprazolam concentrations were less than 10% of the corresponding alprazolam concentration. Mean alprazolam oral clearance values in the three treatment groups ranged between 0.54 and 0.62 ml/min/kg and half-lives were in excess of 21 h. Degree of sedation and impairment was dose related. Sedation and impairment was not higher on day 4 despite concentrations 2-3 times as great as on day 1, indicating development of tolerance. Subjects were not, however, back to baseline level of performance on day 4.

Brotizolam. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy as an hypnotic

Brotizolam is a new thienotriazolodiazepine derivative with a pharmacological profile similar to that of benzodiazepines. It is indicated for use as an hypnotic in the management of insomnia, although it also has anticonvulsant, antianxiety and muscle relaxant properties in animals. In clinical trials brotizolam 0.125 to 0.5mg improved sleep in insomniacs similarly to nitrazepam 2.5 and 5mg, flunitrazepam 2mg and triazolam 0.25mg, whilst brotizolam 0.5mg was shown to be superior to flurazepam 30mg in some studies. Brotizolam is an effective hypnotic for hospital patients awaiting surgery, in whom it also reduces anxiety. Brotizolam has an elimination half-life of about 5 hours, which is 'intermediate' compared with the shorter-acting hypnotic, triazolam, and longer-acting benzodiazepines. Consequently, it is able to induce sleep without producing early morning rebound insomnia, and can also maintain sleep throughout the night. Brotizolam at dosages below 0.5mg at night usually produced minimal morning drowsiness; no residual impairment of psychomotor performance occurs following dosages within the recommended range of 0.125 to 0.25 mg/kg. No serious side effects have been reported to date and the most frequently observed adverse experiences are drowsiness, headache and dizziness. Mild rebound insomnia may occur in some patients when treatment is stopped. Thus, brotizolam is a useful hypnotic which can be used in patients who have difficulty in falling asleep and also in patients who are troubled by night-time awakenings. Used in the recommended dosage it may be particularly useful for patients in whom daytime impairment of performance is unacceptable.

Pharmacokinetics of loprazolam and its principal metabolite in young subjects and elderly hospital patients

1. The pharmacokinetics of loprazolam and its principal pharmacologically active metabolite, the piperazine N-oxide, were compared in young subjects (aged 21-25 years) and elderly patients (aged 63-86 years) following single oral evening doses (0.5 mg and 1 mg). 2. Plasma loprazolam was assayed by a specific h.p.l.c./g.c. method. The N-oxide metabolite was assayed by gas chromography. 3. Mean times to peak plasma concentration of loprazolam did not differ significantly between young and elderly subjects and ranged from 1.6-2.7 h. There was, however, a longer mean time to peak concentration of the N-oxide metabolite in the elderly but this was only statistically different after the 0.5 mg dose (4.5 mg young, 6.4 h elderly). 4. Mean peak plasma concentrations of loprazolam did not differ significantly between young and elderly nor did plasma concentrations of the N-oxide metabolite. 5. Although the mean elimination half-life of loprazolam was not statistically significantly different between young and elderly subjects (range 10.9-16.0 h) there was a trend towards somewhat longer half-lives in the elderly. Furthermore, there was a small but significant increase in the half-life of the N-oxide metabolite in the elderly after the 1 mg dose from 11.7 h to 16.7 h. 6. The areas under the plasma concentration time curves for both loprazolam and its N-oxide were greater in the elderly being some 50-68% (mean 132.0 and 111.5 ng/ml h) above those found in young subjects (mean 89.8 and 66.0 ng/ml h).(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma protein binding of drugs in the elderly

Binding to plasma proteins can affect the pharmacokinetics and pharmacodynamics of drugs. Age is one of many factors which can affect plasma protein binding of drugs. Unfortunately, very few generalities can be drawn from the studies of the effect of age on protein binding. Whether age has an effect on protein binding is dependent not only on the drug, but also on the manner in which the study is conducted. Several studies involve patients with various disease states making assessment of the effect of age alone on protein binding difficult. Results of different studies on the same drug do not always agree--in one case finding no change in protein binding with age and in another, a significant increase or decrease in protein binding. Most drugs which exhibit increased binding (decreased free fraction) in elderly subjects are basic and tend to have a greater affinity for alpha 1-acid glycoprotein than for albumin. The list of drugs exhibiting decreased binding (increased free fraction) in the elderly is longer and includes both acidic and basic drugs. The impact of changes in protein binding with age is dependent on the magnitude of the change, on the pharmacokinetic characteristics of the drug and on its therapeutic index. Some changes, although statistically significant, are not likely to be of importance clinically. From the studies reviewed, the free fraction is changed by greater than 50% in the elderly for only a few drugs, e.g. acetazolamide, diflunisal, etomidate, naproxen, salicylate, valproate and zimeldine.

Pharmacokinetics of temazepam compared with other benzodiazepine hypnotics--some clinical consequences

When the various benzodiazepine hypnotics are studied, large differences are seen with regard to their pharmacokinetic properties and metabolism in man. Some are eliminated from the body at a relatively slow rate (e.g. nitrazepam), others are metabolized rather rapidly (temazepam, triazolam). Some benzodiazepine hypnotics have major active metabolites that are slowly eliminated (flurazepam, quazepam), while others have non-active metabolites (temazepam, lormetazepam). In hypnotic treatment, the duration of drug action should be restricted to the duration of the night, hence a compound with a relatively short elimination half-life may represent a more rational choice. An overview is given of the pharmacokinetics of the currently available benzodiazepine hypnotics with emphasis on temazepam and other hydroxylated benzodiazepines.

Kinetic and dynamic interaction of brotizolam and ethanol

Thirteen healthy male volunteers ingested a single 0.25 mg dose of the thienodiazepine hypnotic, brotizolam, on two occasions: once with a typical social cocktail (containing 60 ml of vodka), and in a second trial with an 'ethanol-placebo' cocktail. Brotizolam kinetics were determined from multiple plasma concentrations measured during the 24 h after dosage. Coadministration of brotizolam with ethanol, as opposed to the placebo cocktail, slightly imparied brotizolam clearance (1.85 vs 2.19 ml min-1 kg-1 P less than 0.005), increased peak plasma concentrations (5.3 vs 4.3 ng ml-1, P less than 0.05), and prolonged elimination half-life (5.2 vs 4.4 h, P less than 0.05). There was evidence of impairment of performance, although not statistically significant, for the first 4-6 h after brotizolam dosage in the reaction time test, the digit-symbol substitution test, and a tracking task. None of these was enhanced by ethanol. In both trials, brotizolam produced significant increases in self-rated perceptions of sedation, fatigue, feeling 'spaced-out', and thinking slowed down. These effects were more intense during the brotizolam-ethanol as compared to brotizolam-placebo. In both trials, recovery was essentially complete by 6-8 h after dosage. Coadministration of brotizolam with ethanol produces a small but significant impairment of brotizolam clearance. Brotizolam produced self-rated perceptions of sedation and fatigue during 4-6 h after dosage, but objective impairment of psychomotor performance was minimal. Subjective perceptions of sedation were enhanced by ethanol coadministration, but the effects on psychomotor performance were not.

Elimination of brotizolam in elderly patients after multiple doses

Plasma brotizolam levels were measured in 5 elderly patients given 0.25 mg daily. The half-life of brotizolam elimination was 6.0 h after a single dose and 6.9 h after continuous administration for 3 weeks. The brotizolam concentration in plasma 2 h after the dose was 3.5 and 3.4 ng/ml, respectively, on the first and last days of the study. Brotizolam levels measured several times during the study 10 h after dosing were between 1.2 and 1.8 ng/ml. Thus, administration of brotizolam 0.25 mg/d to elderly patients for 3 weeks led neither to its accumulation nor to faster elimination. The half-life of brotizolam elimination in elderly patients was in the upper range of that found in young volunteers.

Research in the Division of Pharmacology

Within the Center for Bio-Pharmaceutical Sciences pharmacological research has its emphasis on kinetics of drug disposition, and its interrelationship with pharmacodynamics. The benzodiazepines present a class of related compounds where comparative studies have been performed. Both in humans and in animal models the relationship between plasma levels and central effects has been studied. Also the factors that influence individual responses to the same dose of a drug have been investigated. One of the approaches is the predictive value of antipyrine metabolite formation. Nifedipine shows polymorphism in oxidation, but it is possible to obtain the desired pharmacodynamic effect while minimizing side effects even in slow metabolizers.

Efficacy and acceptability of brotizolam in the elderly

Efficacy of and tolerance to brotizolam were studied over 6 days in elderly patients (62 to 93 years) suffering from sleep disturbance requiring medication: 62.9% used 0.125 mg and 32.0% used 0.25 mg. Effectiveness of brotizolam was assessed as good-to-satisfactory in 87.1% of the patients. Efficacy of and tolerance to brotizolam were compared with nitrazepam in mainly elderly patients (56-91 years) with sleep disturbances requiring medication. Efficacy was assessed as good-to-satisfactory in 89.8% of patients with 0.125 mg brotizolam, 93.9% with 0.25 mg brotizolam and 95.9% with 5 mg nitrazepam. Patients reported improved sleep with all three preparations. The dose range of brotizolam recommended for the elderly is 0.125-0.25 mg, though for the vast majority of patients the lower dose will be sufficient.

Pharmacokinetics of oral brotizolam in patients with liver cirrhosis

Disposition of oral brotizolam (0.5 mg) was studied in male patients with liver cirrhosis (patients) and in other patients (control) matched for age, weight, smoking and drinking habits. Absorption of brotizolam was relatively rapid in both groups with a median peak time (range) of 1.0 (0.5-2.0) h. Peak concentrations were also similar with median values of 7.1 (3.2-10.7) ng/ml in patients and 9.4 (2.9-19.0 ng/ml) in controls. Elimination half-life was longer in patients than in controls. The median values were 12.8 (9.4-25) h and 6.9 (4.4-8.4) h respectively (P less than 0.01). In two patients hardly any drug elimination was observed, indicating severe impairment of drug metabolizing activity. The prolongation of the elimination half-life was likely to be due to a decrease in clearance (45 ml/min in patients compared with 64 ml/min in controls), and an increase in volume of distribution (0.62 l/kg and 0.39 l/kg respectively). Median values of protein unbound fraction of brotizolam were 9.2 (7.8-10.4) % in controls and 12.4 (10.4-18.9) % in patients. Clearance of unbound drug was 612 ml/min and 380 ml/min respectively.