Drug therapy. Current status of benzodiazepines

Low-dose alprazolam augments motor activity in mice

The triazolobenzodiazepine alprazolam appears to have a unique clinical spectrum, and recent studies indicate unusual binding properties at the benzodiazepine receptor when assessed in vivo at low doses (0.02-0.05 mg/kg). To assess the behavioral activity of alprazolam at low doses, we examined open-field activity after one hour in mice treated with alprazolam, triazolam, and clonazepam. Following triazolam and clonazepam administration, open-field activity decreased in a dose-dependent fashion. In contrast, low doses of alprazolam resulted in an increase in open-field activity, whereas higher doses decreased activity. For all three drugs, activity was linearly related to receptor binding. Pretreatment with a dose of the benzodiazepine antagonist Ro15-1788 sufficient to fully occupy receptors had no effect on open-field activity, but when administered concurrently with alprazolam (0.05 mg/kg) prevented the increase in activity seen with alprazolam alone. Increased open-field motor activity represents a behavioral correlate to the increases in receptor binding seen with low-doses of alprazolam. Changes in activity appear to be mediated at the benzodiazepine receptor, since an antagonist prevents increased activity. These data suggest that the unique clinical effects of alprazolam may be due in part to unusual interactions with the benzodiazepine receptor.

Electroencephalographic changes after short-term exposure to agonists of benzodiazepine receptors in the rat

Naive rats receiving IV diazepam (10 mg/kg), flunitrazepam (2.5 mg/kg) and clonazepam (2 mg/kg) show electroencephalographic (EEG) changes consisting of lengthening of the spindle bursts (7-12 Hz; 200-300 microV) and appearance of 15-30 Hz waves (beta-like activity). These EEG manifestations are associated with signs of behavioral sedation (crouched, eyes open and myorelaxation) and stimulation (gnawing, running, ear twitches and sometimes wet-dog shakes), respectively. Bursts of 2-4 Hz waves can be occasionally observed associated with either marked sedation (lying down, eyes closed and presence of righting reflex) or sleep (stretched in the side with absence of righting reflex). Measurements of the periods spent by the animals in the two EEG patterns within the first hour after intravenous injection show the large preponderance of the spindle bursts over the beta-like activity. After the triazolopyridazine Cl 218,872 (10 mg/kg) the beta-like activity is almost absent, and in no case loss of the righting reflex can be observed. These agonists of BDZ receptors have been injected at the above reported doses for 5 days, once-a-day. At the 5th day, animals receiving diazepam exhibit a preponderance of the EEG and behavioral activation within the first hour after injection. Rats receiving flunitrazepam show a significant increase of the periods of stimulation and a slight decrease of the periods of sedation. These phenomena of "habituation" are absent in animals treated with clonazepam and Cl 218,872.

Health of long term benzodiazepine users

The physical and psychological health of long term (over one year) users of benzodiazepines in one general practice was assessed by patients' self reporting of illness and by general practitioners' records. Of 3741 patients registered with the practice, 82 had been prescribed a benzodiazepine, and 64 of these agreed to enter the study. All but five of these patients were over 40 years of age, nearly a third (19) were given a diagnosis related to depression by interviewers, and between a third and a half reported a current physical illness. Long term treatment with benzodiazepines is not necessarily optimum management but may reflect the realities of general practice.

Benzodiazepine receptors in human brain: characterization, subcellular localization and solubilization

1. Benzodiazepine receptors have been characterized in human brain mainly using [3H]-Ro 15-1788 and [3H]-flunitrazepam. Both ligands present a very high affinity for the receptor sites (Kd values of 0.56 and 1.53 nM respectively). 2. GABA enhanced the affinity of [3H]-flunitrazepam and [3H]-diazepam, but not that of [3H]-Ro 15-1788 and [3H]-methyl-beta-carboline 3-carboxylate for their specific binding sites as well in cerebral as in cerebellar human cortex. 3. Subcellular distribution of the benzodiazepine receptors revealed a main synaptosomal localization in human cerebral cortex, cerebellum and striatum. 4. Solubilized benzodiazepine receptors were obtained using 0.5% sodium deoxycholate and were characterized with [3H]-Ro 15-1788. The solubilized receptors are still coupled to GABA receptors since the [3H]-flunitrazepam specific binding was enhanced in the presence of micromolar concentrations of GABA.

The natural history of tolerance to the benzodiazepines

Dependence on benzodiazepines following continued use is by now a well-documented clinical phenomenon. Benzodiazepines differ in their dependence potential. The present studies were aimed at examining the possibility that differential rates of tolerance development might account for differences in dependence risk. Four studies are reported. The first three studies concerned normal subjects. The development of tolerance over a fifteen day period was demonstrated for three different benzodiazepines (ketazolam, lorazepam and triazolam) using two paradigms. Tolerance in terms of a reduction in effectiveness of a repeated given dose was most notable for the benzodiazepine with a medium elimination half-life (lorazepam) for physiological, behavioural and subjective measures. In the case of the drug with the longest elimination half-life (ketazolam) reduction in effectiveness could only be assumed to be occurring if account was taken of the steady increase in plasma concentrations of active metabolites. For this drug it seemed that the physiological measures were those most likely to demonstrate the development of tolerance. Although triazolam showed few significant drug effects on this paradigm (testing being 12 hours after ingestion of this short half-life benzodiazepine), tolerance was seen to develop on some subjective measures. Using an alternative method of testing tolerance, assessing responses to a diazepam challenge dose, a high degree of tolerance on two-thirds of the measures was observed in subjects when pretreated with the benzodiazepine with the most marked accumulation of active metabolites (ketazolam). The other two drugs also led to tolerance development on a range of measures; this was more marked for lorazepam than triazolam. Blunting of the growth hormone response to diazepam was the most sensitive and reliable method of detecting tolerance to the benzodiazepines. Symptoms on discontinuation of the two weeks' intake of the benzodiazepines were marked for all the drugs but unrelated to either the tolerance induced or the elimination half-life of the particular drug. A further clinical study revealed that tolerance persisted in a group of long-term benzodiazepine users for between four months and two years following complete abstinence from the drug. These patients appeared to be less affected by diazepam in terms of its commonly observed subjective effects, regardless of their original medication. These ex-long-term users of benzodiazepines were, however, more likely to manifest two specific types of effects--immediate 'symptom' reduction and exacerbation of 'withdrawal symptoms' over the subsequent week.(ABSTRACT TRUNCATED AT 400 WORDS)

MIF-1 and Tyr-MIF-1 augment GABA-stimulated benzodiazepine receptor binding

Behavioral evidence in laboratory animals and human beings indicates possible links between the endogenous opiate and gamma-aminobutyric acid (GABA)-benzodiazepine receptor systems, especially with regard to antagonistic properties. To assess possible interactions between endogenous opiate antagonists and benzodiazepine receptor binding, we evaluated the effects of the peptides MIF-1 and Tyr-MIF-1 on benzodiazepine receptor binding in mouse brain membranes. Neither peptide affected receptor binding in cortex over a broad dose range, but both peptides significantly augmented GABA-stimulated benzodiazepine receptor binding at GABA concentrations of 10(-8) and 10(-7) M. Rosenthal-Scatchard analysis indicated that the increase in binding was largely due to increased apparent affinity. Both peptides augmented GABA-enhanced binding at low doses (MIF-1 10(-11) M, Tyr-MIF-1 10(-13) M) with decreased effects at higher doses. In cerebellum and brainstem, MIF-1 tended to enhance GABA-stimulated binding but Tyr-MIF-1 was inactive. These results indicate benzodiazepine-opiate and benzodiazepine-peptide interactions.

Benzodiazepines: selective administration

Benzodiazepines are unique chemicals with anxiolytic, anticonvulsant, muscle relaxant and hypnotic properties. Twelve preparations of this group are available in the U.S.A.: two of them belong to the triazolo and one to the 3-nitro groups, the remaining ones are 3-OH or 2-keto benzodiazepines. A number of commonly employed drugs interact with benzodiazepines. Benzodiazepine receptor antagonists which block only one of its actions have been isolated. These promise to lead to preparations with only anxiolytic action without sedation or anticonvulsant action in the future. Guidelines for the selection of the proper drug and for the prevention of dependence are described.

Azaspirodecanediones in generalized anxiety disorder: buspirone

Buspirone is a new anxiolytic that is structurally unrelated to other psychotropic drugs. The drug is as effective as benzodiazepines for the treatment of generalized anxiety, and superior to placebo. The effect of buspirone on other anxiety disorders, such as panic disorder or post-traumatic stress disorder, remains untested. Although buspirone's mechanism of action is unknown, it clearly does not act on the same receptor systems that are affected by benzodiazepines. Buspirone appears to lack dependence and abuse potential and has little or no sedative effect. In addition, the drug does not potentiate sedative-hypnotic drugs and does not potentiate functional impairment produced by alcohol. Like benzodiazepines, buspirone appears to be safe even when given in very high doses.

Central administration of benzodiazepines alters water absorption by the rat ileum in vivo

Two types of benzodiazepine receptors have been identified in the central nervous system. The aim of these experiments was to determine if ligands for these receptors alter basal water absorption by rat ileum in vivo after central administration. Specifically, the effects on net water flux of the systemic and central administration of diazepam and the central administration of RO 5-4864, a "peripheral" receptor agonist, and of the "central" receptor agonists clonazepam and lorazepam were determined. Diazepam increased absorption at 4.3 mg/250 g body wt i.p. but not at 430 micrograms/250 g body wt. Intracerebroventricular diazepam (28 micrograms) increased water absorption. Larger doses had a greater effect. Intracerebroventricular RO 5-4864 (100 micrograms) increased net water absorption; intracerebroventricular lorazepam (50 or 100 micrograms) or clonazepam (100 micrograms) reduced basal water absorption. Systemic atropine (2 mg/kg i.v.) abolished the effect of lorazepam (100 micrograms i.c.v.). To evaluate the possibility that diazepam and RO 5-4864 have effects similar to those of calcium channel antagonists, nifedipine, nitrendipine, and diltiazem were administered intracerebroventricularly. The dihydropyridine calcium channel antagonists nifedipine and nitrendipine increased basal water absorption. Diltiazem, a benzothiazepine compound, did not alter basal water absorption. We conclude that the binding of benzodiazepine agonists to receptors located in the central nervous system alters net water absorption by the rat ileum. Agonists of the central benzodiazepine receptor reduce basal water absorption via a cholinergic neural pathway. Peripheral agonists increase net water absorption. In this model, diazepam behaves as a peripheral receptor agonist. This study provides further evidence of a role for the central nervous system in the regulation of intestinal absorption of water and ions.

Evidence for control of cardiac vagal tone by benzodiazepine receptors

Previous work has suggested that vagal preganglionic neurons which project to the heart, are tonically inhibited by endogenous gamma-aminobutyric acid (GABA). This study tested the hypothesis that benzodiazepines, which are thought to act by enhancing GABAergic inhibition, would increase heart rate by suppressing cardiac vagal activity in anesthetized rats, and that pretreatment with Ro 15-1788, a specific benzodiazepine receptor antagonist, would prevent tachycardia induced by benzodiazepines. Midazolam (0.05-4 mg/kg i.v.), alprazolam (1 mg/kg i.v.) and chlordiazepoxide (10 and 20 mg/kg i.v.), all evoked significant increases in heart rate. Pretreatment with atropine methobromide (2 mg/kg i.v.) increased the basal heart rate and prevented tachycardia induced by benzodiazepines. Basal heart rate and blood pressure were unchanged after pretreatment with Ro 15-1788 (10 mg/kg), but subsequent administration of any of the benzodiazepines failed to elicit increases in heart rate in these animals. These findings suggest that benzodiazepines may be potent vagolytics and that this effect should be considered before these agents are administered to patients who have suffered a recent myocardial infarction, in whom vagal tone is thought to be protective against fatal ventricular arrhythmias.

Buspirone in the treatment of tardive dyskinesia

Buspirone is a novel anxiolytic chemically unrelated to the benzodiazepines. In clinical trials it has been shown to be as effective as diazepam, with fewer side effects. Buspirone is primarily active in dopaminergic pathways. It has the properties of both a dopamine agonist and antagonist. In this paper a model for treatment of tardive dyskinesia with buspirone is developed, based on dopamine autoreceptor blockade. A clinical trial of buspirone in the treatment of movement disorders is warranted.

Lack of evidence of teratogenicity of benzodiazepine drugs in Hungary

In order to investigate possible teratogenic effects of commonly used benzodiazepines (diazepam, chlordiazepoxide, nitrazepam) in Hungary, four approaches were used: 1. A retrospective case-control study of 630 cases with isolated cleft lip +/- cleft palate, 179 cases with isolated cleft palate, 392 cases of multiple congenital anomalies including cleft lip and/or cleft palate, and their matched control cases; 2. The Case-Control Surveillance System of Congenital Anomalies in Hungary, 1980 to 1984, involving 355 cases with isolated cleft palate, 417 cases with multiple congenital anomalies, and 186 cases with Down's syndrome (as positive controls). Benzodiazepines were taken by 14.9% of 11,073 control pregnant women studied; 3. A prospective study of 33 pregnant women attending the Counselling Clinic following ingestion of benzodiazepines during the first trimester of pregnancy; 4. An observational study involving 12 pregnant women who attempted suicide and one with accidental overdosage with benzodiazepines during pregnancy. None of these four approaches gave any indication of an association between facial clefting and in utero exposure to these substances.

Actual versus reported benzodiazepine usage by medical outpatients

Benzodiazepines are widely prescribed, and in 1979 almost 10% of the adult population was taking them. Prior studies of outpatient usage of benzodiazepines have relied on survey or prescription data, which may be confounded by noncompliance. To determine the actual use of benzodiazepines, plasma benzodiazepine concentrations were measured in 225 consecutive outpatients from a university cardiology outpatient service. Self reports indicated that the great majority of the patients (191) were taking at least one medicine, and 70 reported being on a psychotropic drug. Seventy-seven patients reported taking benzodiazepines, the majority being on bromazepam (20), diazepam (26) or oxazepam (19). In 25 of those 77 patients, the reported drug could not be detected in plasma. Conversely, in 10 of the 225 patients, benzodiazepines which were not reported were detected (diazepam or flurazepam). Of those taking benzodiazepines, many had a low concentration, suggesting intermittent rather than regular use. Thus, many patients for whom benzodiazepines are prescribed take them irregularly, and a small group uses them without reporting their prescription. These findings have implications for the clinical presentation of illness and for the possibility of drug interactions.

Optimizing drug treatment of alcohol withdrawal

A number of complications can arise during the drug treatment of alcohol withdrawal, which can be serious or even fatal. Patients who are elderly, have renal or hepatic disease, or are poorly monitored during treatment are particularly prone to problems. By consideration of pharmacologic principles and clinical experience, an optimal drug treatment regimen is formulated that minimizes these risks, while remaining highly effective.

Obesity effects on nitrazepam disposition

Nitrazepam pharmacokinetics were studied in 14 obese (mean +/- s.e. mean body weight 107 +/- 9 kg; percent ideal body weight [IBW] 166 +/- 12%) and 14 normal body weight (63 +/- 3 kg; percent IBW 98 +/- 2%) subjects. After an overnight fast, each subject ingested 10 mg nitrazepam orally. Nitrazepam concentrations were determined in plasma samples obtained over the following 72 h. Comparison of peak nitrazepam plasma concentration (94.2 +/- 10.3-obese vs 119 +/- 14.6 ng ml-1; NS) and time required after drug administration to reach peak concentration (1.52 +/- 0.24-obese vs 1.59 +/- 0.36 h; NS) indicated no differences between obese and control subjects. Elimination half-life was markedly increased in obese subjects (33.5 +/- 2.2 vs 23.9 +/- 1.2 h; P less than 0.001) due to increased apparent volume of distribution (Vd) (290 +/- 45 vs 137 +/- 12 l; P less than 0.005). Oral clearance was also increased in the obese subjects (101 +/- 12.4 vs 66.8 +/- 12.4 ml min-1; P less than 0.02). Extent of nitrazepam binding to plasma proteins was slightly decreased in obese subjects (% unbound--19.7 +/- 0.4-obese vs 17.9 +/- 0.3%; P less than 0.005). Correction of both Vd (2.62 +/- 0.17-obese vs 2.22 +/- 0.19 l kg-1; NS) and clearance (0.93 +/- 0.06-obese +/- 1.07 +/- 0.07 ml min-1 kg-1; NS) for total body weight (TBW) suggested that increases in obese subjects of both of these parameters were a function of body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

A review of alprazolam withdrawal

A cumulative review of case reports in the literature describing withdrawal reactions secondary to alprazolam is presented. In four of eight reports, the primary withdrawal manifestations were grand mal seizures. One case was characterized by painful myoclonus. In the remaining three cases, the major complications consisted of rebound anxiety with psychotic features. Despite tapering of the daily dosage according to manufacturer guidelines, a withdrawal syndrome was precipitated in three of the cases. As a result of alprazolam's atypical pharmacodynamic profile, the issue is raised as to whether alprazolam is pharmacologically cross-tolerant with other benzodiazepines.

Reduction of diazepam serum half life and reversal of coma by activated charcoal in a patient with severe liver disease

We report a case of prolonged coma (7 days) which arose as a complication of the treatment of alcohol withdrawal seizures and delirium with intravenous phenobarbital and diazepam. In an attempt to enhance the elimination of diazepam and its active metabolites, as well as phenobarbital, 40 grams activated charcoal was given every 4 hours (6 doses). Coma was completely reversed within 12 hours; serum half life (t1/2) of diazepam was reduced from 195 to 18 hours during charcoal administration. We postulate that higher free (unbound) diazepam concentrations secondary to hypoalbuminemia, occurring as a result of liver disease, may have increased the depth of our patient's coma, but paradoxically, by making more drug available for diffusion across the gastrointestinal membrane barrier, may have enhanced the ability of activated charcoal to adsorb diazepam and, therefore, decrease its t1/2.

Clinical assessment and pharmacotherapy of the alcohol withdrawal syndrome

All patients in alcohol withdrawal should have a full assessment for detecting medical complications. The Clinical Institute Withdrawal Assessment for Alcohol (CIWA-A) scale permits a quantitative assessment for following the clinical course and therapeutic response in patients in withdrawal. Most patients with mild withdrawal symptoms do not require hospitalization and respond to non-pharmacologic supportive care. Early initiation of treatment with supportive nursing care and, if necessary, benzodiazepines usually will prevent progression to serious withdrawal reactions and provide the patient with sufficient symptomatic relief. Pharmacotherapy can be considerably simplified by using the loading dose technique, i.e., giving diazepam every 1-2 hr initially until the patient shows signs of clinical improvement and/or mild sedation. If long half-life drugs (e.g., diazepam) are used, further therapy is rarely needed and complications are prevented. Short-acting benzodiazepines can also be given in a similar fashion in the milder clinical syndrome. Phenytoin should only be given to patients with a preexisting seizure disorder. Phenothiazines, barbiturates, paraldehyde, and antihistamines have no role in the treatment of withdrawal because of their toxicity or lack of efficacy. Haloperidol is effective in the control of hallucinations in patients also treated with a benzodiazepine. The treatment of alcoholic intoxication and withdrawal is only the first step toward full rehabilitation.

Excellent results with clorazepate in recalcitrant childhood epilepsies

Eleven children with severe incapacitating generalized seizures were treated with sodium valproate and clorazepate and responded with a marked decrease in seizure frequency. Three children received clorazepate alone, either because of valproate toxicity or because of parental concern over side effects. These children, 5 males and 6 females, ranged in age from 3 to 17 years. They manifested normal to severely retarded intelligence. Although valproate levels were in the therapeutic range, seizure control was inadequate. When clorazepate was added to valproate therapy a marked reduction in seizure frequency occurred within 24 hours and became optimal within 48 to 72 hours. Side effects were minimal with the exception of a nocturnal generalized tonic-clonic seizure in a single patient. Three children were withdrawn from therapy after a year because of recurrent seizures. One patient was restarted on therapy after 6 months and seizure control improved. Clorazepate may be a useful adjunct in the treatment of primary generalized seizures in children.

Benzodiazepine receptor-mediated chemotaxis of human monocytes

Benzodiazepines, which are widely prescribed for their antianxiety effects, are shown to be potent stimulators of human monocyte chemotaxis. The chemotactic effects of benzodiazepine receptor agonists were blocked by the peripheral benzodiazepine receptor antagonist PK-11195, suggesting that these effects are mediated by the peripheral-type benzodiazepine receptor. Diazepam was also active in inducing chemotaxis. Binding studies on purified monocytes revealed high-affinity peripheral benzodiazepine receptors, and the displacement potencies of various benzodiazepines correlated with their relative potencies in mediating chemotaxis. The demonstration of functional benzodiazepine receptors on human monocytes, together with recent evidence of receptor-mediated monocyte chemotaxis by other psychoactive peptides (such as opiate peptides), suggests a biochemical substrate for psychosomatic communication.

Effect of a benzodiazepine (alprazolam) on plasma epinephrine and norepinephrine levels during exercise stress

To determine whether a benzodiazepine central nervous system depressant, alprazolam, inhibits sympathetic discharge during exercise stress, 11 healthy men, aged 21 to 35 years, performed symptom-limited treadmill tests before and on the third day of drug therapy (0.5 mg 3 times daily). Plasma epinephrine and norepinephrine levels were measured at rest and at 8 minutes, 11 minutes and maximal exercise. Owing to catheter malfunction during vigorous exercise, paired samples could be obtained from only 8 subjects at 8 minutes and from only 4 subjects at 11 minutes of exercise. During drug treatment, the plasma epinephrine level was lower at rest (30 +/- 4 vs 53 +/- 7 pg/ml, p less than 0.01), and at 8 minutes (60 +/- 13 vs 117 +/- 19 pg/ml, p less than 0.01), 11 minutes (120 +/- 39 vs 193 +/- 52 pg/ml, p less than 0.05), and maximal exercise (520 +/- 125 vs 970 +/- 324 pg/ml, p = 0.13). Plasma norepinephrine was unchanged at rest (452 +/- 57 vs 413 +/- 45 pg/ml) but lower at 8 minutes (730 +/- 75 vs 886 +/- 82 pg/ml, p less than 0.01), 11 minutes (1,077 +/- 197 vs 1,447 +/- 301 pg/ml, p less than 0.05) and at maximal exercise (3,453 +/- 487 vs 5,590 +/- 1,100 pg/ml, p = 0.09). Exercise duration (17 +/- 1 and 17 +/- 1 minutes) was unchanged on drug. Thus, alprazolam reduces the plasma catecholamine response to exercise stress, possibly by inhibiting centrally mediated sympathetic discharge. Blunting of sympathetic activation may be beneficial in cardiac disorders in which increased sympathetic tone is potentially deleterious.

Inhibitory effect of cholesteryl gamma-aminobutyrate on evoked activity in rat hippocampal slices

Cholesteryl gamma-aminobutyrate (C-G) readily crosses the blood-brain barrier and has properties that suggest that it may be a potential gamma-aminobutyric acid (GABA)-mimetic compound. The effect of this compound on the orthodromically-evoked discharge of hippocampal pyramidal cells was investigated using slices of rat hippocampus maintained in vitro. The compound produced dose-dependent inhibition of the discharge of pyramidal cells. The magnitude of the inhibitory effect was somewhat less than that produced by a similar dose of GABA, but the duration of the inhibition was prolonged by about 10-fold over that produced by GABA. The inhibition produced by cholesteryl gamma-aminobutyrate was blocked by the addition of picrotoxin to the incubation medium, and by replacement of chloride with isethionate. In addition, pretreatment of slices with the irreversible esterase inhibitor, phenylmethylsulfonylfluoride, attenuated the effects of cholesteryl gamma-aminobutyrate, but not that of GABA. These results suggest that cholesteryl gamma-aminobutyrate has GABA-like actions in the CNS, and that its activity is largely dependent upon enzymatic release of GABA from the compound by esterases present in the tissue.

Double-blind trial of alprazolam and chlordiazepoxide in the management of the acute ethanol withdrawal syndrome

A sequential sample of 101 patients hospitalized for ethanol withdrawal and requiring sedation for evolving withdrawal syndromes was assigned randomly according to a double-blind protocol to treatment with either alprazolam or chlordiazepoxide administered orally. The data from one patient were unevaluable due to acute bleeding, leaving a sample of 100 (50 in each condition). At discharge, three independent ratings of diaphoresis, tremor, hallucinations, nausea/vomiting, and overall severity of withdrawal were obtained, and the occurrence of delirium tremens and grand mal seizures was noted. Patients also completed the Beck Depression Inventory, and their disposition following discharge was recorded. There were no statistically significant differences between the two treatment groups on any of the dependent variables studied. It was concluded that the choice between alprazolam and chlordiazepoxide for managing ethanol withdrawal should be based on criteria other than efficacy of control. Potential antidepressant effects and drug kinetics were suggested as the basis for rational decision-making.

Antianxiety drugs and central nervous system symptoms in an ambulatory elderly population

Antianxiety agents' effects on the reported frequency of fainting, dizziness, loss of consciousness, and bone fractures were studied in a large ambulatory elderly population. The frequency of these symptoms in participants using seven different antianxiety drugs and that of a control group were compared. Dizziness and episodes of loss of consciousness and falls were reported more frequently in women using these drugs compared with controls (p less than 0.04 and p less than 0.01, respectively). There was an increase in reported bone fractures (12.1 percent to 9.4 percent) in women using antianxiety agents when compared with controls. All central nervous system symptoms were reported more frequently in participants using these drugs when compared with controls. This study suggests that chronic use of antianxiety agents in elderly patients may result in disabling central nervous system side effects.

Use of benzodiazepines in primary-care geriatric patients

From a sample of 257 elderly patients, 93 subjects who had received benzodiazepine (mainly diazepam) prescriptions for one or more years were interviewed about their subjective perception of the drug's effects and their attitudes regarding its use. The subjects were predominantly women: mean age was 72 years. All subjects had begun use of benzodiazepine more than two years earlier, although some had since stopped using the drug; more than a third had used it for more than six years. About half of the subjects said they took no more of the drug than had been initially prescribed, and three quarters reported they took the medications only when a need was felt. The principal indication for use of benzodiazepines was described as tension. Those who were still taking the drug at the time of interview were more likely to live alone and to say that they had the same problems as when they began its use. None of the subjects who had discontinued use of the drugs had been aware of withdrawal symptoms, and there was no evidence that any subject had become addicted, although several expressed a fear of this. It appears that in this age group, prolonged use of benzodiazepine at low doses, with the patients regulating the quantity, is safe and may be helpful. Most subjects, even if not helped, always kept some of the drug at home in case they might need it.

Biomedical causes of alcohol abuse

It is suggested that alcohol, like so many other drugs, is consumed for its rewarding and tension-reducing effects. The progression from use to abuse has many initiating and perpetuating causes at different levels of biological organization, ranging from the molecular to the behavioral level. The interactions between the many causes are better appreciated when they are conceptualized as originating at and progressing from one level to another. Among the perpetuating causes of alcohol abuse may be some of its consequences such as medical diseases and physical dependence. It is hypothesized that at the molecular level an acquired or inherited deficiency of anxiolytic synaptic receptors may be one of several causes of alcohol abuse.

Duration of benzodiazepine clinical activity: lack of direct relationship with plasma half-life. A comparison of single vs divided dosage schedules of prazepam

The anxiolytic activity and tolerance of two dosage schedules of prazepam, a long plasma half-life benzodiazepine, were compared under double-blind conditions in two groups of 10 inpatients each who met Research Diagnostic Criteria for Generalized Anxiety Disorder and presented chronic and severe symptomatology. Patients received prazepam 40 mg per day on one of two dosage schedules: divided dosage (DD) - 10 mg in the morning and at noon and 20 mg in the evening; or single dosage (SD) - 40 mg in the evening. The 3 weeks of therapy were preceded and followed by 1 week of wash-out for baseline and follow-up assessments, which were performed weekly with the Hamilton Anxiety Scale, Clinical Global Impression, rating of morning drowsiness and evening worsening of symptoms, and patient self-rating of anxiety by means of a visual analogue scale performed both in the morning and in the afternoon. The results showed a clear superiority of the DD over the SD schedule: better anxiolytic efficacy on the Hamilton Anxiety Scale (P less than 0.0005) and on both morning and afternoon visual analogue scales (P less than 0.01 and P less than 0.0002); less morning drowsiness (P less than 0.0001); and steadier anxiolytic effect during the daytime, as globally rated by the investigator (P less than 0.0001) or measured by morning-afternoon differences on the visual analogue scale (P less than 0.005). These results suggest that plasma pharmacokinetics alone may not be sufficient to predict the duration of benzodiazepine anxiolytic activity.