Drug therapy. Current status of benzodiazepines

Multiple drug use and psychiatric comorbidity in patients admitted to the hospital with severe benzodiazepine dependence

This study aimed to evaluate the concurrent and lifetime psychiatric comorbidity and drug use patterns in patients admitted to the hospital for detoxification from benzodiazepines. Psychiatric assessments using the Structured Clinical Interview for DSM-III-R with a psychosis screening module (SCID-P and II) were conducted in 30 inpatients admitted to the medical unit treatment unit of the Clinical Research and Treatment Institute of the Addiction Research Foundation for the treatment of severe benzodiazepine dependence. Patients (mean age, 36 years; range, 22-58; number of DSM-III-R criteria met for benzodiazepine substance dependence, > or = 7 out of 9 [73%], all 9 criteria [40%]) used benzodiazepines and other drugs over prolonged periods of time at high doses, and their daily functioning was substantially impaired (Mean Global Assessment of Functioning Score, 48; range, 31-60). The most common lifetime psychiatric diagnoses were major depression (33%), other psychoactive drug dependence (100%) (opioids, 77%; alcohol, 53%), and panic disorder (30%). Current psychiatric diagnoses in addition to benzodiazepine dependence included other psychoactive substance use disorders (83%) (opioids, 67%; cocaine, 13%; multiple concurrent substance use, 17%), panic disorder (13%), and generalized anxiety disorder, (20%). Personality disorders included antisocial (42%), avoidant (25%), and borderline (17%). These findings demonstrate that in patients severely dependent on benzodiazepines, additional psychoactive substance use and mental disorders are prominent. The pattern of drug use and psychiatric comorbidity differentiates these patients from therapeutic-dose benzodiazepine users.

Clinical similarity and biological diversity in the response to alprazolam in patients with panic disorder and generalized anxiety disorder

Thirty-six patients with panic disorder (PD) and 35 patients with generalized anxiety disorder (GAD) participated in an open alprazolam treatment phase that preceded controlled withdrawal from alprazolam. Clinical ratings, blood pressure and heart rate were obtained along with plasma measurements of cortisol, ACTH, growth hormone and catecholamines. A similar clinical response profile was evident in both groups with rapid onset of improvement within the first week. The two diagnostic groups differed in their biological response to alprazolam. PD patients had a significant reduction in blood pressure, plasma cortisol and a trend toward significant reduction in plasma epinephrine, which were not seen in the GAD patients. GAD patients showed a significant reduction in plasma norepinephrine. These findings provide further evidence that PD and GAD are biologically distinct syndromes.

Diazepam potentiates the positive inotropic effect of isoprenaline in rat ventricle strips: role of cyclic AMP

The responses of the electrically driven right ventricle strip of the rat heart to isoprenaline and other cyclic AMP-related inotropic agents were recorded in the absence and in the presence of diazepam. Isoprenaline, in concentrations ranging from 10 nM to 1 microM, significantly increased, in a concentration-dependent manner, the contractile force in this preparation. Diazepam (10 microM) produced a leftward shift in the isoprenaline concentration-response curve and significantly reduced its EC50. Higher concentrations of diazepam (100 microM) produced no further shift, but reduced the maximum of the concentration-response curve of isoprenaline. Forskolin (0.5-10 microM), which directly stimulates adenyl cyclase, also produced a concentration-dependent increase in cardiac contractility. Diazepam (10 microM) displaced to the left the concentration-response curve for forskolin and reduced its EC50. The cyclic AMP analogous dibutyryl cyclic AMP (0.1-1 mM) produced concentration-dependent positive inotropic effects which were not significantly modified in the presence of diazepam (10 microM). Diazepam (10 microM) significantly enhanced the cyclic AMP production induced by isoprenaline (0.1 microM) and forskolin (10 microM) by about 136% and 35% respectively. These results indicate that diazepam potentiates the positive inotropic effect induced by beta-adrenoceptor agonists, probably by increasing cyclic AMP production induced by these agents.

Development and preliminary application of high-performance liquid chromatographic assay of urinary metabolites of diazepam in humans

A simple high-performance liquid chromatographic method for the measurement of diazepam (DZP) and its major metabolites, N-desmethyldiazepam (DMDZP), temazepam (TZP) and oxazepam (OZP) in urine was developed. Preliminary studies of DZP metabolism were also undertaken in four healthy volunteers after administration of a single oral dose (4 mg) of DZP. The assay allowed the simultaneous determination of all analytes in 1 ml of urine and the detection limit was 2 ng/ml with a signal-to-noise ratio of 3. None of 22 drugs and 17 metabolites, except for mianserin, maprotiline and imipramine N-oxide, interfered with the detection of DZP metabolites. Recoveries of the analytes and the internal standard (prazepam) were > 82%. Intra- and inter-assay coefficients of variation for all analytes were < 5.5 and 4.1%, respectively. The mean (+/- S.D.) cumulative urinary excretions of DMDZP, TZP and OZP over 96 h after a single oral administration of DZP were 3.9 +/- 0.4, 6.6 +/- 1.4 and 2.8 +/- 0.6% of the dose, respectively. The urinary excretion of DZP was under the detection limit.

Isolation and structure elucidation of novel products of the acidic degradation of diazepam

The acidic degradation of diazepam in methanolic aqueous solution has been investigated. Apart from the known degradation products, 2-(N-methylamino)-5-chlorobenzophenone and glycine, produced by the hydrolytic cleavage of the benzodiazepinone ring, five novel products were isolated and fully characterized by their spectroscopic features and independent synthesis. Substituted 2-amino-3,5-dichlorobenzophenones and 2,4-dichloroacridinones were found, the formation of which in the reaction media is mechanistically intriguing. The role of these unexpected products in accelerated studies of diazepam stability is discussed.

The benzodiazepines as adjuvant analgesics

There has been long-standing debate regarding whether benzodiazepines possess analgesic properties that are independent of their effects on mood and alertness. A careful review of the literature reveals insufficient evidence to support the contention that the benzodiazepines have meaningful analgesic properties in most clinical circumstances. Treatment with the benzodiazepines may reduce complaints of pain, but this seems to be an indirect effect related to their psychotropic properties, such as alleviation of anxiety and, in selected cases, depression. In the absence of definitive data, clinical experience suggests a potential role for treatment with benzodiazepines for acute muscle spasm, concomitant chronic pain and anxiety, and lancinating neropathic pain, in which case clonazepam and alprazolam may be the agents of choice. They should probably not be considered as first-line choices even for the above indications, since potential benefits must be considered in the context of potential for the development of cognitive impairment, physical and psychological dependence, worsening depression, overdose, and other side effects.

Impact of regulation on benzodiazepine prescribing to a low income elderly population, New York State

On 1 January 1989, in an effort to reduce diversion of benzodiazepines for illicit use and reduce inappropriate prescribing, a regulation was implemented requiring the reporting of all benzodiazepine prescriptions to the New York State Department of Health. To assess the impact of the regulation on prescribing practices to the elderly, we followed the number of benzodiazepines and other central nervous system medications prescribed to a cohort of participants in an elderly pharmaceutical insurance program. Benzodiazepines were prescribed for 4652 (22%) of the 20,944 patients studied. By the last quarter of 1989, benzodiazepines were prescribed for 3120 (15%) patients, a decrease of 33%. The number of prescriptions of benzodiazepines decreased by 5010 (45%), from 11,123 to 6113. Decreases in the number of prescriptions were similar across benzodiazepine brands (range 40-56%). Statistically significant (p < 0.05) decreases were seen in all sex, age, race and marital status groups. Increases in number (and percent increases) of prescriptions for miscellaneous anxiolytics (i.e. hydroxyzine (399, 69%), meprobamate (299, 149%), buspirone (263, 111%), chloral hydrate (138, 265%), antidepressants (658, 19%), barbiturates (150, 29%), and tranquilizers (198, 19%), some of which may be more toxic or less effective, were noted. New York State's reporting regulation was effective in reducing both the number of patients being prescribed benzodiazepines and the number of prescriptions given to those who remain on benzodiazepines in the elderly population studies.

Relationship between subjective effects and drug preferences: ethanol and diazepam

The relationship between subjective effects and drug preferences in normal volunteers was explored in a meta-analysis of several previously published studies. Subjective effects of, and preference for, ethanol and diazepam vs. placebo were measured using a choice procedure. Subjects were grouped according to their drug choices: 'non-choosers' never chose drug, whereas 'choosers' always chose drug. The two groups were compared on their subjective responses to drug and on demographic variables. Ethanol decreased Arousal, Elation, Positive Mood and Vigor, and increased Anxiety, Depression and Fatigue in the non-choosers, whereas it increased Arousal and Vigor in the choosers. Ethanol choosers were also more likely to be males and/or full-time students than non-choosers. Diazepam produced sedative-like effects in both choosers and non-choosers, but markedly decreased Anxiety and increased Friendliness in choosers only. Diazepam choice was also associated with more frequent recreational use of marijuana and stimulants. Thus, both demographic variables and subjective drug effects were related to drug preference.

Alcohol withdrawal: what is the benzodiazepine of choice?

OBJECTIVE

To review the literature concerning the use of benzodiazepines for treatment of alcohol withdrawal and to determine if the current literature assessment justifies the use of lorazepam as first-line therapy.

DATA SOURCES

A thorough review of the literature was performed with an online database (BRS Colleague). Articles directed at the targeted issue were chosen and additional references were obtained from the bibliographies of these articles.

STUDY SELECTION

Clinical trials and case reports concerning the use of chlordiazepoxide, diazepam, and lorazepam in alcohol withdrawal treatment were reviewed.

DATA SYNTHESIS

Lorazepam is considered by many to be the drug of choice for alcohol withdrawal because it undergoes glucuronidation and has an intermediate half-life. These characteristics have suggested its superiority when treating elderly patients or patients with liver disease. However, some studies suggest that a drug with a longer half-life would provide smoother withdrawal. In addition, the number of patients with liver disease treated for alcohol withdrawal is unknown. These and other factors question the recommendation of lorazepam as the drug of choice.

CONCLUSIONS

Well-controlled comparison studies should be performed before recommending the routine use of lorazepam for treating alcohol withdrawal syndrome.

Propranolol versus diazepam in the management of the alcohol withdrawal syndrome: double-blind controlled trial

Thirty-seven male alcoholics admitted electively for detoxification were randomized to treatment with either diazepam or propranolol. Subjects were comparable both in age and in duration and quantity of alcohol consumed. Admission laboratory parameters did not distinguish between the groups. Eleven subjects required no medication to control withdrawal signs/symptoms. Both groups showed improvement in blood pressure, pulse, and withdrawal tremor. None of the subjects randomized to diazepam manifested withdrawal seizures or hallucinations. By contrast, one subject in the propranolol group had a single withdrawal seizure. Another subject manifested increasing withdrawal that required parenteral paraldehyde treatment. Thus, this study confirms that a significant number of subjects admitted electively for alcohol withdrawal can be managed without medication. Minor tranquilizers still remain the "gold standard" for management of the withdrawal syndrome.

Midazolam in patients receiving anticancer chemotherapy and antiemetics

Benzodiazepines lessen anxiety and improve comfort in cancer patients. Midazolam is an effective benzodiazepine with a rapid onset and short duration of action, properties that could permit its use in outpatient areas or in short but stressful situations. Two consecutive trials were undertaken to study midazolam as an adjunct in patients receiving anticancer chemotherapy. Each studied midazolam given as a short infusion 30 min prior to chemotherapy at dose levels ranging from 0.01 to 0.05 mg/kg. Trial I determined the safety, sedation, and dose of midazolam in patients receiving chemotherapy of low to moderate emetic potential. Twenty-two patients were entered. No significant respiratory depression or oxygen desaturation was observed. At the optimal dose level (0.04 mg/kg), sedation began a median of 3 min following administration and continued for a median of 38 min. Sixty-four percent of patients experienced mild sedation. Trial II studied the same doses of midazolam when used in combination with intravenous metoclopramide and dexamethasone in patients receiving cisplatin > or = 100 mg/m2. Nineteen patients were entered; 79% experienced mild sedation. At the 0.04-mg/kg dose level, sedation began a median of 18 min following administration and continued for a median of 170 min. Midazolam can be given safely to patients receiving chemotherapy with and without concomitant antiemetics. The predictability and duration of its sedative effects suggest it can be used in outpatients.

Long-term drug treatment of panic disorder

Drug treatment of panic disorder with benzodiazepines and antidepressants has been established as efficacious in the short-term (6-8 weeks). The efficacy of medications during long-term (i.e., continuous) treatment has not often been addressed and a review of the evidence is presented. Most data exists for the long-term effectiveness of benzodiazepines. Experience with the triazolobenzodiazepine, alprazolam, is reviewed together with some other high potency drugs, e.g., clonazepam. Tricyclic antidepressants are also effective in the long-term treatment of panic and the relevant studies are presented. Long-term efficacy for monoamine oxidase inhibitors is not as clearly established. The issue of relapse following drug withdrawal is addressed and some strategies for patient management in long-term therapy are discussed.

Benzodiazepine receptor binding of benzodiazepine hypnotics: Receptor and ligand specificity

Benzodiazepine (BDZ) hypnotics bind at a specific receptor located on postsynaptic neurons. Some data support specificity of binding for several hypnotics to receptor subtypes. We evaluated BDZ receptor binding in cerebral cortical membranes using agonist, antagonist, and subtype-specific ligands for commonly used hypnotics and their metabolites. All hypnotics competed similarly at BDZ1 and BDZ2 receptor subtypes except quazepam and its metabolite 2-oxo-quazepam and to a lesser extent hydroxyethyl flurazepam (EtOH) flurazepam. These compounds had relative specificity for the BDZ1 site. Triazolam, estazolam, and flurazepam bound equally to sites labeled by agonists and antagonists but desalkylflurazepam, EtOH flurazepam, temazepam, quazepam, and 2-oxo-quazepam did not; in addition, these four compounds did not bind to the "peripheral" BDZ site labeled by Ro 5-4864. BDZ hypnotics differ in their receptor subtype and ligand binding characteristics.

Effects of zopiclone on subjective evaluation of sleep and daytime alertness and on psychomotor and physical performance tests in athletes

1. In a double-blind cross-over study 8 athletes received during 2 sessions of 2 nights zopiclone (7.5 mg) or placebo. 2. Residual effects on subsequent daytime functions were evaluated both subjectively by visual analogue scales as well as objectively by a test battery measuring psychomotor and physical skills. 3. Zopiclone had some favourable effects on self-estimated sleep quality and daytime sleepiness. 4. Psychomotor and physical performance tests did not show any significant difference between zopiclone and placebo. 5. We conclude that zopiclone has useful hypnotic activity without significant adverse effects on athletic performance.

Response of three hormones to diazepam challenge in sons of alcoholics and controls

This study evaluates the hypothesis that the decreased reaction to ethanol reported for sons of alcoholics will also be observed following infusions of a benzodiazepine. The investigation compared 37 men who were family history positive for alcoholism with 37 family history negative controls on postinfusion levels of cortisol, prolactin, and growth hormone following 0.12 and 0.20 mg/kg of diazepam given IV over 7 minutes. The results demonstrated no evidence of a decreased response for the sons of alcoholics on the levels of these three hormones.

Persistent elevation in GABAA receptor subunit mRNAs following social stress

Stress is associated with alterations in GABA/benzodiazepine binding and function. We evaluated effects of social stress on GABAA receptor subunit (alpha 1 and gamma 2) mRNAs by Northern hybridization. In cortex, no change was observed in either subunit mRNA immediately after stress, but a 4 hours mRNAs for both subunits were increased. These changes persisted for 72 hours after stress, and returned to baseline levels at 7 days. No changes in mRNAs were observed in sham-treated mice. No changes in either subunit mRNA were observed in stressed or sham-treated mice in cerebellum or hippocampus. In undefeated resident mice, mRNAs for both subunits in cortex were unaffected at 24 hours after the stress episode. Social stress is associated with increases in GABAA receptor alpha 1 and gamma 2 subunit mRNAs in cortex.

Measuring anxiety in nonhuman primates: effect of lorazepam on macaque scratching

Lorazepam (0.2 mg/kg IM) was given to group-living female macaques to assess the effect of anxiolytic treatment on scratching, a behavior pattern referred to as a displacement activity in the primate literature. Lorazepam selectively diminished scratching behavior. The drug effect was status-dependent: especially low-ranking animals showed a marked reduction in scratching. Lorazepam exerted a direct effect on scratching, that is the effect was not due to sedation or mediated by the influence of the drug on other behaviors. These results provide pharmacological validation to the ethological finding that scratching may be a manifestation of anxiety in monkeys. In addition, they suggest to use scratching as a behavioral measure in studies investigating nonhuman primate models of anxiety.

A guide to benzodiazepine selection. Part II: Clinical aspects

To suit the specific needs of various clinical situations, selection of an appropriate benzodiazepine derivative should be based on consideration of their different pharmacokinetic and pharmacodynamic properties. Benzodiazepine derivatives that are rapidly eliminated produce the most pronounced rebound and withdrawal syndromes. Benzodiazepines that are slowly absorbed and slowly eliminated are most appropriate for the anxious patient, since these derivatives produce a gradual and sustained anxiolytic effect. Rapidly absorbed and slowly eliminated benzodiazepines are usually more appropriate for patients with sleep disturbances, since the rapid absorption induces sleep and the slower elimination rate may induce less tolerance to the sedative effect. Rational selection of a benzodiazepine for the elderly and for the suspected drug abuser is more problematic. The relevant pharmacokinetic and clinical considerations for these users are discussed. Certain derivatives may possess pharmacodynamic properties not shared by the entire benzodiazepine class; empirical studies have suggested the existence of anti-panic properties for alprazolam and clonazepam, antidepressant properties for alprazolam, and anti-manic properties for clonazepam and possibly lorazepam.

Pharmacologic aspects of benzodiazepine tolerance and dependence

Benzodiazepines, which are among the safest and most effective drugs, possess all the characteristic of abuseable compounds. Although there appear to be differences in potency among compounds and variations in sensitivity among individuals, benzodiazepines have clear reinforcing properties. Tolerance to the depressant effects of benzodiazepines is rapid, but tolerance to the anxiolytic effects develops slowly and to a limited extent. Although abusers use very high doses, most long-term users persist at daily doses in the low therapeutic range (10-20 mg of diazepam or its equivalent) without dose escalation. Physical dependence is a risk associated with long-term use, even at therapeutic doses. The withdrawal syndrome is mild at low doses. Continued self-administration of low therapeutic doses is maintained to alleviate withdrawal symptoms. The advances in the recent understanding of the molecular biology of the benzodiazepine receptor gives hope to the development of new anxiolytic compounds with less dependence liability than the present ones.

Prenatal exposure to benzodiazepine--I. Prenatal exposure to lorazepam in mice alters open-field activity and GABAA receptor function

Prenatal exposure to benzodiazepines may lead to developmental abnormalities in humans and animals. To assess the behavioral and neurochemical effects of such exposure, pregnant mice were treated with lorazepam, 2 mg/kg/day, from days 13-20 of gestation, and open-field activity was assessed in offspring at 3 and 6 weeks of age and the function of GABAA receptors at 6 weeks of age. Activity was increased in mice exposed to lorazepam, compared to untreated or vehicle-treated controls at 3 weeks, but was unchanged at 6 weeks. Muscimol-stimulated uptake of chloride was decreased in lorazepam-treated mice, compared to controls, with a decrease in maximum uptake but no change in the EC50 for muscimol. Concentrations of lorazepam in maternal plasma and brain showed a similar brain:plasma ratio as previously reported and concentrations in fetal brain were about 50% of maternal levels. Lorazepam persisted for 48 hours after birth in dams but not in the offspring. These results indicate persistent behavioral and neurochemical alterations after prenatal exposure to lorazepam. This model may be useful in assessing other effects of prenatal exposure to benzodiazepine.

A guide to benzodiazepine selection. Part I: Pharmacological aspects

Since absorption rates, volumes of distribution and elimination rates differ greatly among the benzodiazepine derivatives, each benzodiazepine has a unique plasma concentration curve. Although the time to peak plasma levels provides a rough guide, it is not equivalent to the time to clinical onset of effect. Two half-lives can be described: the alpha half-life, the rate of decline in plasma concentrations due to the process of drug redistribution from the central to the peripheral compartment, and the beta half-life, the rate of decline due to the process of drug elimination due to metabolism. The frequent classification of benzodiazepines into long, intermediate, and short-"acting" categories based on their terminal beta half-lives is unfounded; the duration of action is much more dependent on the alpha half-life. Benzodiazepines with short beta half-lives are commonly thought to be preferable because they accumulate less. However, with repeated use, sedation and cognitive neuromotor impairment usually diminish progressively despite stable or even rising benzodiazepine plasma concentrations, whereas anxiolytic effects generally persist over time.

Diazepam (Valium): its dependency liability

Reports of the withdrawal syndrome following discontinuation of diazepam and drug dependence fears have contributed to diazepam's displacement as the most popular anxiolytic agent. Reports of the withdrawal syndrome, the factors involved in withdrawal, and the remedies proposed for diazepam withdrawal symptoms are reviewed.

Decreased density of benzodiazepine receptors in lymphocytes of anxious patients: reversal after chronic diazepam treatment

Peripheral-type benzodiazepine receptors were measured in human circulating lymphocytes using 3H-PK 11195 as specific ligand. In a group of outpatients with anxiety disorders a significant decrease of receptor density (-37%) was found compared with age-matched controls. In these patients long-term diazepam treatment restored binding density to normal levels: the effect persisted after drug withdrawal. Acute i.v. diazepam administration did not change receptor density. The observed receptor changes could reflect a down-regulation phenomenon and indicate that lymphocyte function reflect central nervous events.

Chronic benzodiazepine antagonist treatment and its withdrawal upregulates components of GABA-benzodiazepine receptor ionophore complex in cerebral cortex of rat

Effect of chronic administration of benzodiazepine (BZ) receptor antagonist Ro 15-1788 (flumazenil) (4 mg/kg once daily for 14 days) treatment and its withdrawal on locomotor activity, body temperature, and the binding pattern of receptor ligands that bind to GABA-BZ receptor ionophore complex in different regions of the brain of the rat was studied. Ro 15-1788 (x 14 d) increased the specific binding of [3H]ethyl-8-fluoro-5-6-dihydro-5-methyl-6-oxo-4H- imidazo[1,5 alpha][1,4]benzodiazepine-3-carboxylate [( 3H]Ro 15-1788), [3H]ethyl-8-azido-5-6-dihydro-5-methyl-6-oxo-4H- imidazo[1,5 alpha][1,4]benzodiazepine-3-carboxylate [( 3H]Ro 15-4513), [3H]flunitrazepam, and [35S]t-butylbicyclophosphorothionate [( 35S]TBPS) in cerebral cortex, and this increase in binding remained upregulated during the drug withdrawal at 24 h. The binding of [3H]Ro 15-1788 was also found significantly increased in the hippocampus, but not in cerebellum and striatum. The chronic Ro 15-1788 treatment did not alter the specific binding of [3H]GABA. Rosenthal analysis of the saturation isotherms indicated that the observed upregulation in the binding pattern of [3H]Ro 15-1788 and [3H]Ro 15-4513 in the cerebral cortex was due to an increase in the binding capacity (Bmax). The receptor affinity (Kd) was not changed. The withdrawal of Ro 15-1788 following its chronic administration also enhanced locomotor activity. However, no apparent change in body temperature was observed either due to chronic treatment or withdrawal. These data indicate that chronic Ro 15-1788 treatment and its withdrawal may produce an upregulation of subunits which bind the positive (benzodiazepines), negative (inverse agonist), and neutral (antagonist) ligands of benzodiazepine receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Estazolam and flurazepam: a multicenter, placebo-controlled comparative study in outpatients with insomnia

A multicenter, double-blind placebo-controlled clinical trial was designed to compare the safety and efficacy of estazolam compared with flurazepam as hypnotics. Outpatients complaining of insomnia were randomized to receive either estazolam 2 mg, flurazepam 30 mg or placebo for 7 consecutive nights. The analysis of efficacy was based on the patients' daily assessments of sleep and the investigators' global evaluations. Adverse events which were considered by the investigator to be attributable to, or of unknown relationship to the test medication were analyzed. The patient subjective questionnaire indicated that estazolam and flurazepam significantly improved all parameters (P less than .05) as compared to placebo. A marked or moderate improvement in sleep was reported by 81% (58/72), 78% (63/81) and 36% (27/76) of estazolam, flurazepam, and placebo recipients, respectively. There were no significant differences in hypnotic effect between estazolam and flurazepam. All efficacy parameters of the investigators' global evaluation improved significantly more (P less than .05) for patients receiving estazolam or flurazepam (except quality of sleep) than for those receiving placebo. The percentage of patients reporting any adverse experience was greatest for flurazepam (72%), followed by estazolam (59%), and placebo (43%). Somnolence and hypokinesia were the most commonly reported adverse events. An analysis of the global evaluation of side effects showed that flurazepam had a significantly worse side effect profile than estazolam (P less than .05) or placebo (P = .001). Estazolam and flurazepam effectively, and comparably, relieved insomnia when administered for 7 nights in adult patients complaining of insomnia. Estazolam demonstrated a more favorable side effect profile than flurazepam.

Chlorpyrifos toxicosis in two cats

Organophosphate compounds are widely employed for control of external parasites in cats and for control of insects in homes and yards. Chlorpyrifos is a long-acting organophosphate (OP) available for use as a systemically and topically acting parasiticide and insecticide in cattle. Its use on cats is not recommended, and no previous clinical cases of toxicosis have been described. Two cases of chronic chlorpyrifos toxicosis in cats are presented and pathophysiology as well as treatment are discussed. The cats had been showing signs of chronic organophosphate toxicosis before diazepam administration. Signs of acute organophosphate toxicosis were precipitated after diazepam was given. Treatment with pralidoxime chloride (2-PAM) and atropine was attempted. Response to treatment was dramatic and complete recovery was achieved with six injections of pralidoxime and atropine administration.

Growth hormone response to intravenous diazepam and placebo in 82 healthy men

Growth hormone (GH) response to placebo and two different doses of diazepam (0.12 mg/kg and 0.20 mg/kg) were evaluated in 82 healthy young men. Both diazepam doses had a significant effect on the growth hormone secretion, with peak values occurring between 30 and 60 min postinfusion, after which levels returned to baseline. There was also a small but significant change in this hormone over time after placebo, but this was reflected by a slow rise following the saline infusion. Individual GH responses to diazepam were variable and, when a cut-off point of 7.5 ng/ml GH increase before 90 min postdrug administration was used, 1% of the men demonstrated a response after placebo, 17% after low-dose diazepam, and 37% following high-dose diazepam. The clinical implications and limitations of these findings are discussed.

Use of flumazenil in intoxicated patients with coma. A double-blind placebo-controlled study in ICU

In a double-blind placebo-controlled prospective clinical trial we studied the efficacy and safety of the benzodiazepine antagonist, flumazenil. In 23 patients admitted to the Intensive Care Unit with coma due to overdose with benzodiazepines or other sedatives, flumazenil i.v. (up to 2 mg or placebo) was given. In 13 patients given flumazenil the Glasgow Coma Scale (GCS) increased significantly from 4.9 to 7.8 (p less than 0.05). Six of these 13 patients, including mainly benzodiazepine mono-intoxications, needed only one series of injections (up to 1.0 mg flumazenil); the GCS increased thereby from 4.5 to 10.7 within a maximum of 5 min (p less than 0.01). In the remaining 7 patients, needing two series of injections of flumazenil (up to 2.0 mg), GCS did not rise significantly and coma was related to intoxications with nonbenzodiazepine sedatives, flunitrazepam and in one patient, encephalitis. In the 10 patients receiving placebo, the GCS did not change. A significant increase in the GCS from 5.5 to 10.8 (p less than 0.001) was, however, observed when flumazenil (up to 1.0 mg) was given after placebo. In patients with EEG monitoring the changes in waveform pattern paralleled the clinical response. Effects could be detected within 1-2 min after flumazenil injection and lasted up to 45 min. There were no adverse reactions or benzodiazepine withdrawal symptoms. We conclude that flumazenil is an effective and safe drug in the treatment of benzodiazepine overdose. The use of flumazenil is of diagnostic value in mixed-drug intoxications or coma of unknown origin and is of therapeutic importance for reversal of benzodiazepine intoxications.

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.

Changes in the prescription patterns of psychotropic drugs for cancer patients during a 10-year period

The use of psychotropic drugs was studied in 200 cancer patients admitted to a medical oncology unit at Memorial Sloan-Kettering Cancer Center, New York, in December 1987. When compared with a similar survey that studied prescription practices 10 years ago, there was a 30% increase in the use of psychotropic agents. Whereas prescription rates for different drug classes remained relatively stable, psychotropic drugs are now used for a greater range of reasons. The introduction of several new agents, especially short-acting benzodiazepines, has altered the physician's choices. Despite awareness of the different properties of psychotropic medications and their increased use, they are still underused, especially the antidepressants and antipsychotics when prescribed for psychologic distress.

The benzodiazepines as drugs of abuse

Benzodiazepines are rarely used as "party" or "good time" drugs. Recent studies of drug abuse liability have found that benzodiazepines are minor euphoriants: they are neither sought nor valued on the same level as cocaine, methaqualone, or even alcohol. Although they do have mild to moderate euphoriant effects in recreational drug users, detoxified chronic alcoholics and, at very high dosages, detoxified sedative "addicts", only a small proportion of patients entering drug abuse treatment programs cite benzodiazepine use as their primary drug problem. However, it is difficult to estimate the extent to which benzodiazepines are primary drugs of abuse, i.e. the extent of their ability to induce euphoria with psychic dependence and active drug-seeking behavior. This may be due in part to inconsistent or ambiguous reporting terminology and reliance on laboratory studies without comparisons with actual street use. In addition, it is unclear if patients admitted to emergency rooms for non-medical use of benzodiazepines are typical of all patients who abuse these drugs. This article will examine the current data available on benzodiazepine abuse and will assess the extent to which benzodiazepines are used as primary drugs of abuse.

Interaction of caffeine with the GABAA receptor complex: alterations in receptor function but not ligand binding

Behavioral and neurochemical evidence indicates interactions between caffeine and other adenosine receptor ligands and the gamma-aminobutyric acid (GABA)-benzodiazepine system. To assess the effects of caffeine on binding and function at the GABAA receptor, we studied the effects of behaviorally-active doses of caffeine on benzodiazepine and Cl- channel binding and on overall function of the GABAA receptor as measured by Cl- uptake. There was no effect of caffeine on benzodiazepine receptor binding in cortical synaptosomal membranes at concentrations of 1-100 microM. No effects on benzodiazepine binding were found ex vivo in mice treated with caffeine, 20 and 40 mg/kg. At the putative Cl- channel site labeled by t-butylbicyclophosphorothionate (TBPS), binding was unchanged in vitro after caffeine treatment (1 and 10 microM) in washed and unwashed membranes. However, in ex vivo studies caffeine (20 and 40 mg/kg) increased numbers of TBPS sites in unwashed but not washed membranes. Muscimol-stimulated Cl- uptake into cortical synaptoneurosomes was decreased in mice treated with caffeine, 20 and 40 mg/kg. Similar results were observed in in vitro preparations treated with 50 microM but not 100 microM caffeine. These results indicate that caffeine administration significantly alters the Cl- transport function of the GABAA receptor complex.

Chronic benzodiazepine administration. IV. Rapid development of tolerance and receptor downregulation associated with alprazolam administration

The triazolobenzodiazepine compound alprazolam may have unique clinical effects compared to other benzodiazepines, and both behavioral and neurochemical studies have indicated unusual results after acute doses of alprazolam. To determine the effects of chronic dosage in mice, alprazolam (2 mg/kg/day) was administered via osmotic pumps for 1-14 days, and open-field activity, plasma and brain concentrations, benzodiazepine receptor binding in vivo and in vitro, [35S]t-butylbicyclophosphorothionate ([35S]TBPS) binding, and muscimol-stimulated chloride uptake were determined. Alprazolam decreased motor activity after 1 and 2 days, but tolerance developed by day 4 and persisted to day 14. Plasma and brain concentrations remained constant during the 2-week period. Benzodiazepine receptor binding in vivo was decreased at day 4 compared to day 1 in cortex (CX) and hypothalamus (HYPO), and remained depressed to day 14 in CX but not HYPO. Benzodiazepine binding in vitro and [35S]TBPS binding were decreased in CX at day 7. Muscimol-stimulated [36Cl-] uptake was decreased at days 4 and 7 compared to day 1, but at day 14 uptake was similar to day 1. These results indicate that behavioral tolerance and receptor downregulation develop rapidly during chronic alprazolam administration. Behavioral and neurochemical changes were similar to those associated with lorazepam administration, but occurred more rapidly and with different regional specificity.

Lorazepam discontinuation promotes 'inverse agonist' effects of benzodiazepines

1. The effects of lorazepam discontinuation on responses to benzodiazepine agonists and antagonists were studied in mice. 2. The convulsant dose of pentylenetetrazol was decreased after an acute dose of lorazepam (0.5 mg kg-1) at 4 days after drug discontinuation, compared to 1 or 7 days after discontinuation or to vehicle treatment. 3. The percentage of mice undergoing convulsions after an acute dose of FG 7142 (40 mg kg-1) was increased at 4 days after lorazepam discontinuation, compared to 1 or 7 days after discontinuation or to vehicle treatment. 4. After an acute dose (0.5 mg kg-1), lorazepam concentrations in cortex tended to be greater in lorazepam-treated compared to vehicle-treated mice at 4 days after discontinuation compared to 1 and 7 days. 5. These data indicate a shift toward reduced agonist sensitivity and increased inverse agonist sensitivity in mice 4 days after lorazepam discontinuation.

Reinforcing and subjective effects of diazepam in nondrug-abusing volunteers

Preference for diazepam was assessed in 18 light and 12 moderate social drinkers using a cumulative dosing procedure. The 7-session procedure consisted of: 1) four sampling sessions, during which participants ingested color-coded capsules containing either diazepam (five 4-mg capsules administered at 30-min intervals; total dose 20 mg) or placebo, and 2) three choice sessions, during which they could ingest up to 7 capsules of their preferred color of capsule, each separated by 30 min. Subjective (mood) and behavioral (performance) measures were obtained throughout the 4-hour sessions. The light social drinkers chose diazepam over placebo on 66% of the choice sessions, and ingested a mean dose per session of about 16 mg. The moderate drinkers chose diazepam on 100% of the choice sessions, and ingested an average dose of 25 mg per session. Diazepam produced sedation in both groups, but in the moderate drinkers it also increased measures of subjective effects suggestive of "euphoria." The results indicate that diazepam can serve as a positive reinforcer under laboratory conditions in nondrug-abusing individuals who are moderate users of alcohol and other drugs. Greater reinforcing efficacy may be indicative of higher risk of abuse. The results illustrate the usefulness of the cumulative dosing procedure to measure both drug preference and dose preference.

Double blind study on the efficacy and safety of tetrabamate and chlordiazepoxide in the treatment of the acute alcohol withdrawal syndrome

1. Efficacy and safety of tetrabamate and chlordiazepoxide in the treatment of the acute or Primary Alcohol Withdrawal Syndrome (PAWS) were assessed during a randomized double blind clinical trial, carried out on sixty male alcoholic in-patients. 2. The two drugs were administered four times a day in double dummy conditions, according to a fixed-flexible decreasing dosage schedule (six days basic regimen). 3. Drug efficacy was measured daily throughout the study period using a battery of standard instruments for collecting quantitative clinical, behavioral, psychopathological and laboratory data. Side effects were daily recorded. 4. Tetrabamate was found to be as efficient as chlordiazepoxide in reducing the intensity of the PAWS, improving sleep and vital signs rapidly and alleviating anxiety progressively. 5. Tetrabamate was found particularly beneficial for severe tremor. Psychomotor and mood scores consistently favored tetrabamate, suggesting psychoanaleptic properties of this compound (increased diurnal vigilance). 6. Side effects were minimal with tetrabamate and generally of weak intensity with chlordiazepoxide. 7. The results of this study indicate that tetrabamate may represent a new alternative drug of choice for the therapy of the acute alcohol withdrawal syndrome.

Lorazepam administration during embryonic development alters GABAA receptor binding and function

Prenatal exposure to diazepam has been reported to lead to behavioral alterations in young and mature animals, but the neurochemical basis of this effect is uncertain. To examine effects of embryonic benzodiazepine exposure on the gamma-aminobutyric acidergic (GABA)ergic) system, we assessed binding and function at the GABAA receptor complex in chick embryos treated with lorazepam, 2 mg/kg, for 2-10 days. There was no change in benzodiazepine receptor binding in cortex after lorazepam administration, but a decrease in the number of chloride channel sites was observed. Overall function at the GABAA receptor complex as assessed by chloride uptake into cortical synaptoneurosomes was decreased after 10 days of lorazepam, and possibly increased after 4 days of lorazepam. Similar results were obtained when embryos were treated for 2- and 4-day periods beginning on day 8. These results indicate that chronic lorazepam administration to embryos alters binding and function in the GABA system measured soon before hatching. These alterations, if persistent, may contribute to the behavioral changes seen in animals exposed prenatally.

Relative abuse liability of lorazepam and diazepam: an evaluation in 'recreational' drug users

The subjective, psychomotor and cognitive effects of oral doses of lorazepam (0, 1.5, 3 and 6 mg) and diazepam (0, 10, 20 and 40 mg) were studied under double-blind conditions in 14 volunteers with histories of 'recreational' benzodiazepine use/abuse. For each subject, drug was administered over 4 test days in a 2 (drug) by 4 (dose level) mixed design. Drug was the between-groups factor while dose was the within-subjects factor. Test days were separated by at least 1 week. The results showed that subjective ratings of drug 'liking' and the psychomotor and cognitive effects of lorazepam were generally similar to those of diazepam over the range of doses studied. Lorazepam, however, tended to produce effects of longer duration than diazepam. Since previous studies have shown that diazepam has a relatively high abuse liability among the benzodiazepines, the present findings suggest that lorazepam shares this property with diazepam is subjects with a history of 'recreational' drug use/abuse.

Meprobamate use in the elderly. A report from the Dunedin program

Meprobamate use was studied in an ambulatory elderly population in Dunedin, Florida. All participants taking this medication were mailed a questionnaire concerning their pattern of use. From 2,278 subjects, 30 (1.3%) reported the use of this drug. The average age of participants using this drug was 81.3 years. Five participants began using the drug over 27 years ago and over one-half of the respondents reported using the drug on a regular basis for over 10 years. With this type of history of meprobamate use, one might expect to encounter a large number of patients in the future who, in a similar manner, have been using benzodiazepines for many decades.

Benzodiazepine abuse and management of anxiety in the community

Medication is largely inappropriate in the management of anxiety, and benzodiazepines are not apparently effective in the minor affective disorders commonly seen in general practice (Catalan and Gath, 1985). Enough has been said to indicate that other measures are likely to be more helpful and to reduce the tendency to prescribe benzodiazepines. The taking of these drugs threatens to become epidemic and while medical agencies are by no means the only sources, sensible prescribing will go--and may already have gone, as the DHSS (1986) figures suggest--some way toward limiting consumption of these drugs. The DHSS needs to record more specific data relating to benzodiazepine use and abuse. Comparative trials of benzodiazepines and alternative non-benzodiazepine methods of anxiety management need to be set up as matter of urgency. The (no doubt) false impression that the pharmaceutical industry is dragging its feet in planning and sponsoring such trials should be speedily dispelled. Benzodiazepine prescribing, if it increases, may well in itself become a major danger to public health.