Current benzodiazepine issues

ANXIOLYTICS: Origins, drug discovery, and mechanisms

Anxiety is a part of the human condition and has been managed by psychoactive substances for centuries. The current medical need and societal demand for anxiolytic medicines has not abated. The present overview provides a brief historical introduction to the discovery of modern age anxiolytics that include the benzodiazepines together with a discussion of the continuing medical need for new antianxiety medications. The paper also discusses the use and impact of behavioral pharmacology in the preclinical development of anxiolytics. The review then highlights the diversity of mechanisms for creating a new generation of anxiolytics through mechanisms beyond the potentiation of GABAA receptors and the blockade of monoamine uptake. A discussion then follows on the behavioral specificity of action of anxiolytics that includes the concept of creating an anxioselective drug, one that targets anxiety without producing untoward effects that include sedation and dependence. The use of anxiolytics in the treatment of other conditions such as substance use disorder is also briefly reviewed. Finally, a brief summary of the current status of anxiolytic drug development is provided. The review concludes with the idea that despite a host of anxiolytic drugs, the lack of efficacy in some patients and the side-effects and safety issues associated with some of these medications demands alternative medicines. Current preclinical and clinical research is ongoing with the goal of identifying such compounds.

Free Amine-Directed Redox Neutral Ruthenium(II) Catalysis toward Regioselective Synthesis of Heterobiaryls

A regioselective coupling of ortho-heteroaryl anilines and 7-oxabenzonorbornadienes has been developed by leveraging free amine-directed redox-neutral Ru(II) catalysis. This protocol facilitates formal C-2 arylation of the indole moiety under mild conditions to offer valuable heterobiaryls in high yields. The reaction displays a broad substrate generality and scalability and retains efficacy in the presence of diverse pharmacophore scaffolds. Moreover, products bearing a free amine group were successfully employed in Mg(NTf2)2-catalyzed double Michael addition cascade, which led to the synthesis of intricate indole- and pyrrole-fused azaheterocycles.

Novel Designer Benzodiazepines: Comprehensive Review of Evolving Clinical and Adverse Effects

As tranquilizers, benzodiazepines have a wide range of clinical uses. Recently, there has been a significant rise in the number of novel psychoactive substances, including designer benzodiazepines. Flubromazolam(8-bromo-6-(2-fluorophenyl)-1-methyl-4H-[1,2,4]triazolo[4,3-a][1,4]benzodiazeZpine) is a triazolo-analogue of flubromazepam. The most common effects noted by recreational users include heavy hypnosis and sedation, long-lasting amnesia, and rapid development of tolerance. Other effects included anxiolysis, muscle-relaxing effects, euphoria, loss of control, and severe withdrawals. Clonazolam, or 6-(2-chlorophenyl)-1-methyl-8-nitro-4H-[1,2,4]triazolo[4,3-α]-[1,4]-benzodiazepine, is a triazolo-analog of clonazepam. It is reported to be over twice as potent as alprazolam. Deschloroetizolam (2-Ethyl-9-methyl-4-phenyl-6H-thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine) is part of the thienodiazepine drug class, which, like benzodiazepines, stimulates GABA-A receptors. Meclonazepam ((3S)-5-(2-chlorophenyl)-3-methyl-7-nitro-1,3-dihydro-1,4-benzodiazepin-2-one) is a designer benzodiazepine with additional anti-parasitic effects. Although it has proven to be an efficacious therapy for schistosomiasis, its sedative side effects have prevented it from being marketed as a therapeutic agent. The use of DBZs has been a subject of multiple recent clinical studies, likely related to increasing presence and availability on the internet drug market and lack of regulation. Many studies have aimed to identify the prevalence of DBZs and their effects on those using them. This review discussed these designer benzodiazepines and the dangers and adverse effects that the clinician should know.

Effects of the α2/α3-subtype-selective GABAA receptor positive allosteric modulator KRM-II-81 on pain-depressed behavior in rats: comparison with ketorolac and diazepam

This study examined effects of the α2/α3-subtype-selective GABAA receptor positive allosteric modulator KRM-II-81 in an assay of pain-related behavioral depression. Adult, male Sprague-Dawley rats responded for electrical brain stimulation in a frequency-rate intracranial self-stimulation (ICSS) procedure. Intraperitoneal injection of 1.8% lactic acid served as an acute noxious stimulus to depress ICSS. Effects of KRM-II-81 were evaluated in the absence and presence of the acid noxious stimulus. The NSAID ketorolac and the benzodiazepine diazepam were tested as comparators. Neither ketorolac nor KRM-II-81 altered ICSS in the absence of the acid noxious stimulus; however, diazepam produced facilitation consistent with its abuse liability. Ketorolac blocked acid-induced depression of ICSS, and effects of 1.0 mg/kg ketorolac lasted for at least 5 h. KRM-II-81 (1.0 mg/kg) produced significant antinociception after 30 min that dissipated by 60 min. Diazepam also attenuated acid-depressed ICSS, but only at doses that facilitated ICSS when administered alone. The lack of ketorolac or KRM-II-81 effects on ICSS in the absence of the acid noxious stimulus suggests low abuse liability for both compounds. The effectiveness of ketorolac to block acid-induced ICSS depression agrees with clinical analgesic efficacy of ketorolac. KRM-II-81 produced significant but less consistent and shorter-acting antinociception than ketorolac.

Drug misuse in older people: old problems and new challenges

Very little attention has been paid to the invisible epidemic of substance misuse among older people in the UK. This article looks at the prevalence of substance misuse in the people over the age of 60. The reasons for difficulty in diagnosing substance misuse are explored and ways to improve diagnostic ability are discussed. Substance misuse leads to severe physical and psychiatric morbidity that is being managed by meagre resources. The article provides recommendations on specific issues related to interventions, biological and psychosocial, and training of psychiatrists.

Abuse-related effects of subtype-selective GABAA receptor positive allosteric modulators in an assay of intracranial self-stimulation in rats

RATIONALE

GABA_A positive allosteric modulators (GABA_A PAMs), such as diazepam and zolpidem, are used clinically for anxiety and insomnia, but abuse liability is a concern. Novel GABA_A PAMS may have lower abuse liability while retaining clinical utility.

OBJECTIVE

The present study compared abuse-related effects of the non-selective GABA_A PAM diazepam, the α1-selective GABA_A PAM zolpidem, and three novel GABA_A PAMs (JY-XHe-053, XHe-II-053, and HZ-166) using intracranial self-stimulation (ICSS) in rats. These novel compounds have relatively low efficacy at α1-, α2-, and α3-containing GABA_A receptors, putative in vivo selectivity at α2/α3-containing GABA_A receptors, and produce anxiolytic-like effects with limited sedation in non-human primates.

METHODS

Adult, male Sprague-Dawley rats (n = 17) were each implanted with a bipolar electrode in the medial forebrain bundle and trained to respond under a fixed-ratio 1 schedule of reinforcement for electrical brain stimulation. The potency and time course of effects were compared for diazepam (0.1-10 mg/kg), zolpidem (0.032-3.2 mg/kg), and the three novel compounds (JY-XHe-053, XHe-II-053, and HZ-166; all 3.2-32 mg/kg).

RESULTS

Zolpidem and diazepam produced transient facilitation of ICSS at small doses and more sustained rate-decreasing effects at larger doses. JY-XHe-053 and HZ-166 produced weak and inconsistent ICSS facilitation, whereas XHe-II-053 had no effect on ICSS.

CONCLUSIONS

These results support a key role for α1-containing GABA_A receptors in mediating GABA_A PAM-induced ICSS facilitation. These results are concordant with drug self-administration studies in monkeys in suggesting that GABA_A PAMs with low α1 efficacy and putative α2/α3 selectivity have lower abuse liability than high-efficacy non-selective or α1-selective GABA_A PAMs.

Assessment of the Abuse Potential of the Orexin Receptor Antagonist, Suvorexant, Compared With Zolpidem in a Randomized Crossover Study

Suvorexant is a dual orexin receptor antagonist approved in the United States and Japan for the treatment of insomnia at a maximum dose of 20 mg. This randomized double-blind crossover study evaluated the abuse potential of suvorexant in 36 healthy recreational polydrug users with a history of sedative and psychedelic drug use. Single doses of suvorexant (40, 80, and 150 mg: 2-7.5 × maximum dose), zolpidem (15 and 30 mg: 1.5-3 × maximum dose), and placebo were administered, with a 10-day washout between treatments. Subjective and objective measures, including visual analog scales (VASs), Addiction Research Center Inventory, and cognitive/psychomotor tests, were evaluated for 24-hour postdose. Suvorexant had significantly greater peak effects on "drug liking" VAS (primary endpoint) than placebo. Although effects of suvorexant on abuse potential measures were generally similar to zolpidem, they remained constant across doses, whereas zolpidem often had greater effects at higher doses. Suvorexant (all doses) had significantly fewer effects than zolpidem 30 mg on secondary measures, such as "high" VAS, Bowdle VAS, and Addiction Research Center Inventory morphine-benzedrine group. The overall incidence of abuse-related adverse events, such as euphoric mood and hallucination, was numerically lower with suvorexant than zolpidem. In agreement with its classification as a schedule IV drug, suvorexant demonstrated abuse potential, compared with placebo. The abuse potential was similar to zolpidem using certain measures, but with a reduced incidence of abuse-related adverse events. Although this suggests that the overall abuse liability of suvorexant may be lower than zolpidem, the actual abuse rates will be assessed with the postmarketing experience.

A tryptic hydrolysate from bovine milk αs1-casein enhances pentobarbital-induced sleep in mice via the GABAA receptor

Studies have shown that enzymatic hydrolysis of casein, the primary protein component of cow's milk, produces peptides with various biological activities, and some of these peptides may have sleep-promoting effects. In the present study, we evaluated the sedative and sleep-promoting effects of bovine αS1-casein tryptic hydrolysate (CH), containing a decapeptide αS1-casein known as alpha-casozepine. CH was orally administered to ICR mice at various concentrations (75, 150, 300, or 500mg/kg). An hour after administration, assessment of its sedative (open-field and rota-rod tests) and sleep-potentiating effects (pentobarbital-induced sleeping test and EEG monitoring) were conducted. Although a trend can be observed, CH treatment did not significantly alter the spontaneous locomotor activity and motor function of mice in the open-field and rota-rod tests. On the other hand, CH (150mg/kg, respectively) enhanced the sleep induced by pentobarbital sodium in mice. It also promoted slow-wave (delta) EEG activity in rats; a pattern indicative of sleep or relaxation. These behavioral results indicate that CH has sleep-promoting effects, but no or has minimal sedative effects. To elucidate the probable mechanism behind the effects of CH, we examined its action on intracellular chloride ion influx in cultured human neuroblastoma cells. CH dose-dependently increased chloride ion influx, which was blocked by co-administration of bicuculline, a competitive GABAA receptor antagonist. Taken together, the results of the present study suggest that CH has sleep-promoting properties which are probably mediated through the GABAA receptor-chloride ion channel complex.

Taking Policy Action to Reduce Benzodiazepine Use and Promote Self-Care Among Seniors

This article reviews current knowledge on the risks and benefits of benzodiazepine use for seniors and addresses potential policies that could be made to reduce use and support sentors' mental health. Although seniors are only 12% to 15% of the population, they consume between 35% and 52% of all benzodiazepines prescribed in Canada and the United States. Despite significant long-term use among seniors, relatively few studies demonstrate the efficacy of more than short-term use for anxiety and insomnia. There is significant data to suggest that use is associated with increased potential for injury, cognitive and memory deficits, and a dependency syndrome. This article argues that the current controversy rests not so much in the scientific data but in the willingness of clinicians to interpret and act on that information. As internationally developed guidelines for practice suggest that benzodiazepine treatment for anxiety and insomnia may not be without risks, other first-line treatments should be developed.

Enhancing Spatial Memory: Anxiolytic and Antidepressant Effects of Tapinanthus dodoneifolius (DC) Danser in Mice

We evaluated the anxiolytic and antidepressant effects of the aqueous extract of the bark of Tapinanthus dodoneifolius (TAE) (Danser) (25, 50, and 100 mg/kg), using open field, elevated plus maze, and forced swimming tests. Effect of TAE was compared to standard drugs diazepam (2 mg/kg) and imipramine (10 mg/kg). Additionally, the same doses of TAE were evaluated on rat's memory using Y-maze task. Results showed a significant (P < 0.05; 100 mg/kg) increase in the percentage of open arm entry and the time spent in the open arms in the elevated plus maze, suggesting an anxiolytic activity of the extract. In a dose-dependant manner, TAE at 25 mg/kg significantly (P < 0.05) decreased the number of lines crossed and the rearing behavior in the open field test, suggesting its possible sedative activity. In the forced swimming test, the immobility time of the animal was significantly reduced (P < 0.05) by TAE (100 mg/kg), compared to control, and this effect was quite comparable to that of imipramine. In the Y-maze paradigm, TAE at 50 mg/kg caused a significant increase in the spontaneous alternations but with a significant decrease in exploratory behavioral pattern. Taking these results together, TAE improved the spatial memory and showed anxiolytic, antidepressant, and sedative activities. The present results support the anxiolytic and antidepressant activities of TAE and, to our knowledge, for the first time, demonstrate its enhancing effect on memory.

Insomnia pharmacotherapy

The benzodiazepine receptor agonists (BzRAs) a melatonin receptor agonist and a histamine antagonist have all been approved as hypnotics. Beyond their differing mechanisms of action, they have differences in pharmacokinetics, and among the BzRAs differences in receptor subtype affinity and formulations, which provides the physician with broad options for tailoring therapy to each patient's specific needs. Consistent with their specific pharmacokinetics and formulations, these Food and Drug Administration-approved hypnotics have been shown to improve sleep with no evidence of tolerance development in long-term use. In addition, emerging data indicate these drugs also improve aspects of daytime function. Their side effects are either associated with the direct sedating effects of the drugs, doses greater than clinical doses, or a combination with alcohol or other sedating drugs. Anxiolytic BzRAs, sedating antidepressants and antipsychotics have been used off-label as hypnotics. However, in the absence of information regarding their dose range for efficacy and safety, their use as hypnotics is ill-advised.

Determinants of initiated and continued benzodiazepine use in the Netherlands study of depression and anxiety

BACKGROUND

Longitudinal research on determinants of initiated and continued benzodiazepine (BZD) use is inconsistent and has identified many possible determinants. It is unclear which of those are most important in the prediction of BZD use. We aimed to identify the most important predictors of initiated and continued BZD use. Therefore, we analyzed the most consistently identified determinants from previous research plus some new determinants.

METHODS

We identified baseline and 2-year longitudinal predictors of initiated BZD use (vs nonuse) among 2205 baseline BZD nonusers and of continued use (vs discontinued use) among 369 baseline BZD users in the Netherlands Study of Depression and Anxiety using logistic regression analyses.

RESULTS

During follow-up, BZD use was initiated by 4.9% of BZD nonusers at baseline. Initiated use was predicted by insomnia (odds ratio [OR], 1.60), enduring anxiety symptoms (OR, 2.02), entering secondary care during follow-up (OR, 2.85), and past BZD use (OR, 3.57). Positive life events during follow-up reduced the likelihood of BZD initiation (OR, 0.76). Of BZD users at baseline, 54.2% continued use during the entire follow-up period. Continuation of BZD use was predicted by higher age (OR, 1.03), severe anxiety (OR, 1.85), and a long duration of BZD use (OR, 1.54). Leaving secondary care was associated with less continued BZD use (OR, 0.29).

CONCLUSION

Insomnia and anxiety were the main risk factors of initiated use, whereas advanced age and anxiety severity were the main risk factors of continued use. Sex, education, pain, and physical health seemed to be less important.

Twelve months of nightly zolpidem does not lead to dose escalation: a prospective placebo-controlled study

STUDY OBJECTIVES

To assess hypnotic self-administration and likelihood of dose escalation over 12 months of nightly use of zolpidem versus placebo in primary insomniacs.

DESIGN

Randomized, double-blind, placebo-controlled, clinical trial.

SETTING

Outpatient with tri-monthly one-week, sleep laboratory assessments.

PARTICIPANTS

Thirty-three primary insomniacs, without psychiatric disorders or drug and alcohol abuse, 32-64 yrs old, 14 men and 19 women.

INTERVENTIONS

Participants were randomized to take zolpidem 10 mg (n = 17) or placebo (n = 16) nightly for 12 months. In probes during month 1, 4, and 12, after sampling color-coded placebo or zolpidem capsules on 2 nights, color-coded zolpidem or placebo was chosen on 5 consecutive nights and 1, 2, or 3 of the chosen capsules (5 mg each) could be self-administered on a given choice night.

RESULTS

Zolpidem was chosen more nights than placebo (80% of nights) and number of nights zolpidem was chosen did not differ over the 12 months. More zolpidem than placebo capsules were self-administered, and the total number of placebo or zolpidem capsules self-administered did not differ as a function of duration of use. In contrast, the total number of placebo capsules self-administered by the placebo group increased across time. The nightly capsule self-administration on zolpidem nights did not differ from that on placebo nights and neither nightly self-administration rates increased over the 12 months. An average 9.3 mg nightly dose was self-administered.

CONCLUSIONS

Zolpidem was preferred to placebo, but its self-administration did not increase with 12 months of use. Chronic hypnotic use by primary insomniacs does not lead to dose escalation.

GABAA receptor alpha2/alpha3 subtype-selective modulators as potential nonsedating anxiolytics

Nonselective benzodiazepines exert their pharmacological effects via GABAA receptors containing either an alpha1, alpha2, alpha3, or alpha5 subunit. The use of subtype-selective tool compounds along with transgenic mice has formed the conceptual framework for defining the requirements of subtype-selective compounds with potentially novel pharmacological profiles. More specifically, compounds which allosterically modulate the alpha2 and/or alpha3 subtypes but are devoid of, or have much reduced, effects at the alpha1 subtype are hypothesized to be anxioselective (i.e., anxiolytic but devoid of sedation). Accordingly, three compounds, MRK-409, TPA023 and TPA023B, which selectively potentiated the effects of GABA at the alpha2 and alpha3 compared to alpha1 subtypes were progressed into man. All three compounds behaved as nonsedating anxiolytics in preclinical (rodent and primate) species but, surprisingly, MRK-409 produced sedation in man at relatively low levels of occupancy (< 10%). This sedation liability of MRK-409 in man was attributed to its weak partial agonist efficacy at the alpha1 subtype since both TPA023 and TPA023B lacked any alpha1 efficacy and did not produce overt sedation even at relatively high levels of occupancy (> 50%). The anxiolytic efficacy of TPA023 was evaluated in Generalized Anxiety Disorder and although these clinical trials were terminated early due to preclinical toxicity issues, the combined data from these incomplete studies demonstrated an anxiolytic-like effect of TPA023. This compound also showed a trend to increase cognitive performance in a small group of schizophrenic subjects and is currently under further evaluation of its cognition-enhancing effects in schizophrenia as part of the TURNS initiative. In contrast, the fate of the back-up clinical candidate TPA023B has not been publicly disclosed. At the very least, these data indicate that the pharmacological profile of compounds that differentially modulate specific populations of GABAA receptors is distinct from classical benzodiazepines and should encourage further preclinical and clinical investigation of such compounds, with the caveat that, as exemplified by MRK-409, the preclinical profile might not necessarily translate into man.

Withdrawing benzodiazepines in primary care

The use of benzodiazepine anxiolytics and hypnotics continues to excite controversy. Views differ from expert to expert and from country to country as to the extent of the problem, or even whether long-term benzodiazepine use actually constitutes a problem. The adverse effects of these drugs have been extensively documented and their effectiveness is being increasingly questioned. Discontinuation is usually beneficial as it is followed by improved psychomotor and cognitive functioning, particularly in the elderly. The potential for dependence and addiction have also become more apparent. The licensing of SSRIs for anxiety disorders has widened the prescribers' therapeutic choices (although this group of medications also have their own adverse effects). Melatonin agonists show promise in some forms of insomnia. Accordingly, it is now even more imperative that long-term benzodiazepine users be reviewed with respect to possible discontinuation. Strategies for discontinuation start with primary-care practitioners, who are still the main prescribers.This review sets out the stratagems that have been evaluated, concentrating on those of a pharmacological nature. Simple interventions include basic monitoring of repeat prescriptions and assessment by the doctor. Even a letter from the primary-care practitioner pointing out the continuing usage of benzodiazepines and questioning their need can result in reduction or cessation of use. Pharmacists also have a role to play in monitoring the use of benzodiazepines, although mobilizing their assistance is not yet routine. Such stratagems can avoid the use of specialist back-up services such as psychiatrists, home care, and addiction and alcohol misuse treatment facilities.Pharmacological interventions for benzodiazepine dependence have been reviewed in detail in a recent Cochrane review, but only eight studies proved adequate for analysis. Carbamazepine was the only drug that appeared to have any useful adjunctive properties for assisting in the discontinuation of benzodiazepines but the available data are insufficient for recommendations to be made regarding its use. Antidepressants can help if the patient is depressed before withdrawal or develops a depressive syndrome during withdrawal. The clearest strategy was to taper the medication; abrupt cessation can only be justified if a very serious adverse effect supervenes during treatment. No clear evidence suggests the optimum rate of tapering, and schedules vary from 4 weeks to several years. Our recommendation is to aim for withdrawal in <6 months, otherwise the withdrawal process can become the morbid focus of the patient's existence. Substitution of diazepam for another benzodiazepine can be helpful, at least logistically, as diazepam is available in a liquid formulation.Psychological interventions range from simple support through counselling to expert cognitive-behavioural therapy (CBT). Group therapy may be helpful as it at least provides support from other patients. The value of counselling is not established and it can be quite time consuming. CBT needs to be administered by fully trained and experienced personnel but seems effective, particularly in obviating relapse.The outcome of successful withdrawal is gratifying, both in terms of improved functioning and abstinence from the benzodiazepine usage. Economic benefits also ensue.Some of the principles of withdrawing benzodiazepines are listed. Antidepressants may be helpful, as may some symptomatic remedies. Care must be taken not to substitute one drug dependence problem for the original one.

Emerging anti-insomnia drugs: tackling sleeplessness and the quality of wake time

Sleep is essential for our physical and mental well being. However, when novel hypnotic drugs are developed, the focus tends to be on the marginal and statistically significant increase in minutes slept during the night instead of the effects on the quality of wakefulness. Recent research on the mechanisms underlying sleep and the control of the sleep-wake cycle has the potential to aid the development of novel hypnotic drugs; however, this potential has not yet been realized. Here, we review the current understanding of how hypnotic drugs act, and discuss how new, more effective drugs and treatment strategies for insomnia might be achieved by taking into consideration the daytime consequences of disrupted sleep.

Abuse and dependence liability of benzodiazepine-type drugs: GABA(A) receptor modulation and beyond

Over the past several decades, benzodiazepines and the newer non-benzodiazepines have become the anxiolytic/hypnotics of choice over the more readily abused barbiturates. While all drugs from this class act at the GABA(A) receptor, benzodiazepine-type drugs offer the clear advantage of being safer and better tolerated. However, there is still potential for these drugs to be abused, and significant evidence exists to suggest that this is a growing problem. This review examines the behavioral determinants of the abuse and dependence liability of benzodiazepine-type drugs. Moreover, the pharmacological and putative biochemical basis of the abuse-related behavior is discussed.

Minimizing antipsychotic medication obviated the need for enema against severe constipation leading to paralytic ileus: a case report

OBJECTIVE

To report the usefulness of antipsychotic dose-reduction for avoiding paralytic ileus in a patient with chronic schizophrenia and comorbid dementia.

CASE SUMMARY

A 65-year-old in-patient developed severe paralytic ileus warranting a transfer to the general hospital. Constipation was very troublesome and he often needed enema to prevent intestinal obstruction. He had originally been treated with 24 mg of bromperidol, which was reduced to 4 mg, and other psychotropic treatments were simultaneously simplified. As a result, bowel habits improved and enema is now only rarely necessary. Constipation is a frequent adverse effect of antipsychotics and adjunctive psychotropics, which can be severe and may lead to life-threatening paralytic ileus. Dose-reduction obviated a necessity of enema against persistent constipation, while the patient's mental status remained under control. Assessment using the Naranjo probability scale revealed a definite causal relationship.

DISCUSSION

With an increasing number of elderly patients with schizophrenia, more cases of severe gastrointestinal motility problems from antipsychotic medication are to be expected. In this patient population dose-reduction of antipsychotics and simplification of concomitant psychotropics should be seriously considered.

Psychoactive drug abuse in older adults

BACKGROUND

Misuse and abuse of legal and illegal drugs constitute a growing problem among older adults.

OBJECTIVE

This article reviews the prevalence, risks and protective factors, and screening and diagnosis of drug abuse in older adults. Treatment concerns and the consequences of drug problems are examined briefly.

METHODS

MEDLINE and PsychInfo were searched using the terms substance-related disorders, drug-use disorders, abuse, dependency, opioid-related disorders, stimulant-related disorders, cocaine-related disorders, marijuana-related disorders, and withdrawal syndrome. The review included articles published in English between January 1, 1990, and May 31, 2006.

RESULTS

Despite a wealth of information on the epidemiology and treatment of alcohol abuse in older adults, few comparable data are available on drug abuse in this population. The evidence suggests that although illegal drug use is relatively rare among older adults compared with younger adults and adolescents, there is a growing problem of the misuse and abuse of prescription drugs with abuse potential. It is estimated that up to 11% of older women misuse prescription drugs and that nonmedical use of prescription drugs among all adults aged > or =50 years will increase to 2.7 million by the year 2020. Factors associated with drug abuse in older adults include female sex, social isolation, history of a substance-use or mental health disorder, and medical exposure to prescription drugs with abuse potential. No validated screening or assessment instruments are available for identifying or diagnosing drug abuse in the older population. Special approaches may be necessary when treating substance-use disorders in older adults with multiple comorbidities and/or functional impairment, and the least intensive approaches should be considered first.

CONCLUSIONS

Psychoactive medications with abuse potential are used by at least 1 in 4 older adults, and such use is likely to grow as the population ages. The treatment of disorders of prescription drug use in older adults may involve family and caretakers, and should take into account the unique physical, emotional, and cognitive factors of aging. Further research is needed on the epidemiologic, health services, and treatment aspects of drug abuse in older adults, as well as the development of appropriate screening and diagnostic tools.

Metabolism of a 14C/3H-labeled GABAA receptor partial agonist in rat, dog and human liver microsomes: Evaluation of a dual-radiolabel strategy

The metabolism of 2-{[2-(3-fluoropyrid-2-yl)-1H-imidazol-1-yl]methyl}-1-propyl-5-cyano-1H-benzimidazole (1), a potent subtype-selective GABA(A) receptor partial agonist, was investigated in rat, dog and human liver microsomes. Due to its significant metabolic cleavage at C(8) observed in preliminary biotransformation studies with non-radiolabeled 1, both [(14)C]1 and [(3)H]1 were synthesized with respective radioisotopes placed on either side of C(8) to determine if all microsomal metabolites formed after C(8)N-dealkylation of 1 (or its core-intact metabolites) could be detected and quantified adequately. Both radiolabeled forms of 1, used separately in mono-radiolabel studies in cross-species microsomes and concomitantly in dual-radiolabel studies in rat microsomes, permitted the detection and quantification of all metabolites of 1, and a combination of radioactive and mass spectral data allowed structural elucidation of its Phase I metabolites. As expected, the sum of (14)C-only metabolites equaled that of (3)H-only metabolites in all incubations. In-line radiometric analysis worked extremely well (and was very reproducible) for quantifying either (14)C- or (3)H-compounds within separate incubations when using mono-radiolabeled 1. However, although the in-line radiodetector provided a comprehensive qualitative metabolic profile using dual-radiolabled 1, its inability to exclude completely (14)C- from (3)H-generated counts caused a degree of ambiguity pertaining to metabolite quantification. Thus, off-line liquid scintillation counting of collected dual-radiolabeled incubation LC-fractions was employed to quantify both (14)C- and (3)H-metabolites simultaneously, while in-line radiodetection was only used for qualitative analyses accompanying MS and MS/MS experiments. These studies demonstrated the analytical feasibility of using a dual-radiolabel approach for subsequent in vivo ADME studies with 1.

Gas-phase fragmentation of protonated benzodiazepines

Protonated 1,4-benzodiazepines dissociate in the gas phase by the common pathway of CO elimination and by unique pathways dictated by the substituents; the latter typically differentiate one benzodiazepine from another. Protonated 3-dihydro-5-phenyl-1,4-benzodiazepin-2-one, the base diazepam devoid of substituents, dissociates by eliminating CO, HNCO, benzene, and benzonitrile. Mechanisms of these reactions are proposed with ionic products being resonance stabilized. The abundant [MH-CO]+ ion dissociates to secondary products via elimination of benzene, benzonitrile, the NH2 radical, and ammonia, yielding again ionic products that are stabilized by resonance.

Comparison of sleep condition and sleep-related psychological activity after cognitive-behavior and pharmacological therapy for chronic insomnia

BACKGROUND

Previous studies of insomnia focused mainly on the improvement of sleep condition and ignored the effects of sleep-related psychological activity and daytime function after pharmacological and behavioral treatments. We compared the clinical effects of both therapies on sleep condition, sleep-related psychological activity and daytime function in chronic insomnia.

METHODS

Seventy-one patients with chronic insomnia were randomly divided into 4 groups and either received cognitive-behavior therapy (CBT, n = 19), pharmacological therapy (PCT, n = 17), CBT plus medication (Combined, n = 18) or placebo (n = 17). The treatments lasted for 8 weeks with follow-ups conducted at 3 and 8 months. On the day after treatment ended, all patients were assessed using a polysomnogram (PSG), a sleep diary and a psychological assessment.

RESULTS

The three active treatments were more effective than placebo at the time the treatments were completed. Subjective sleep-onset latency, sleep efficacy and total sleep time were better in the PCT group than in the CBT group. At the 3-month follow-up, subjective and objective sleep-onset latency, sleep efficacy and total sleep time were better in the CBT group than in both the PCT and the Combined group. At the 8-month follow-up, the CBT group showed a steady comfortable sleep state, while the PCT and Combined groups were gradually returning to the pre-treatment condition. The Combined group showed a variable long-term effect. On the other hand, pre-sleep arousal at nighttime, dysfunctional beliefs about sleep as well as daytime functioning in the CBT group not only improved, but was better than in the other active treatment groups.

CONCLUSION

Medication and Combined therapy produced a short-term effect on chronic insomnia while CBT had a long-term effect of improved sleep-related psychological activity and daytime functioning.

The relationship between past-year drinking behaviors and nonmedical use of prescription drugs: prevalence of co-occurrence in a national sample

This study examined the relationship between past-year drinking behaviors and nonmedical use of prescription drugs (NMUPD) in a nationally representative sample. Prevalence estimates in the United States were derived based on data collected from face-to-face interviews using the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) (n=43,093 individuals aged 18 years and older). Nonmedical use of prescription opioids, stimulants, tranquilizers, and sedatives was more prevalent among individuals with alcohol use disorders (AUDs) than those without AUDs. The odds of reporting NMUPD were 18 times higher among alcohol dependent participants compared to past-year abstainers (OR=18.2, 95% CI=13.9-23.8). Although individuals with AUDs constituted less than 9% of the total sample, those with AUDs accounted for more than one in every three nonmedical users of prescription drugs. The past-year co-occurrence of AUDs and NMUPD was more prevalent among young adults 18-24 years of age than individuals 25 years and older. More than one in every four young adults aged 18-24 years who met the criteria for past-year DSM-IV alcohol dependence also reported past-year NMUPD. These findings suggest that the treatment for AUDs should include a thorough assessment of NMUPD, especially among young adults.

The benzodiazepine binding site of GABA(A) receptors as a target for the development of novel anxiolytics

Non-selective benzodiazepine (BZ) binding-site full agonists, exemplified by diazepam, act by enhancing the inhibitory effects of GABA at GABA(A) receptors containing either an alpha1, -2, -3 or -5 subunit. However, despite their proven clinical anxiolytic efficacy, such compounds possess a relatively narrow window between doses that produce anxiolysis and those that cause sedation, and are also associated with physical dependence and a potential for abuse. In the late 1980s and early 1990s a number of non-selective partial agonists, exemplified by bretazenil, pazinaclone and abecarnil, were described. Their reduced intrinsic efficacy relative to full agonists such as diazepam resulted in an improved preclinical pharmacological profile in that there was a large window between anxiolytic and sedative doses and their dependence and abuse liabilities were much lower. Unfortunately, these compounds failed, for a variety of reasons, to translate into clinical benefit, and as the public perception of BZs deteriorated interest in the area waned. However, the advent of molecular genetic and pharmacological approaches has begun to delineate which GABA(A) receptor subtypes are associated with the various pharmacological effects of the non-selective BZs. More specifically, the alpha2- and/or alpha3-containing GABA(A) receptors play a role in anxiety whereas the alpha1 subtype is involved in sedation, raising the possibility of a compound that selectively modulates alpha2- and/or alpha3-containing receptors but does not affect alpha1-containing receptors would be a non-sedating anxiolytic. In order to achieve selectivity for the alpha2/alpha3 subtypes relative to alpha1, two approaches may be used; selective affinity or selective efficacy. Selective affinity relies on a compound binding with higher affinity to the alpha2/alpha3 compared with alpha1 subtypes, but to date no such compounds have been described. On the other hand, subtype-selective efficacy relies on a compound binding to all subtypes but having different efficacies at various subtypes (relative selective efficacy, for example SL654198 or pagoclone) or having efficacy at some subtypes but none at others (absolute selective efficacy; for example, L-838417). The status of these and other BZ site compounds with claimed, but often not explicitly stated, GABA(A) subtype selectivity (such as ELB-139 and ocinaplon) will be reviewed in relation to their development as non-sedating anxiolytics for the treatment of generalised anxiety disorder.

National Estimates of Exposure to Prescription Drugs with Addiction Potential in Community-Dwelling Elders

The use of prescription drugs with addiction potential is an overlooked and growing problem among today's elderly. This paper provides national prevalence estimates of exposure to prescription drugs with addiction potential among community-dwelling elders and explores risk factors for such exposure. Using the Medicare Current Beneficiary Survey, a nationally-representative database of Medicare eligibles, we calculated the prevalence of abusable prescription drug use, overall, by therapeutic class, and by drug. Nearly 22% (7.22 million) of all community-dwelling Medicare elders used at least one prescription medication with addiction potential. Opioid analgesics were used most frequently (14.9%; 95% CI 14.0, 15.8%); central nervous system (CNS) depressants were used by 10.4% of the nation's elders (95% CI 9.5, 10.8%). Using logistic regression analysis, we examined the association of explanatory variables with three outcome variables: any controlled substances use, any opioid analgesic use, and any CNS depressant use. We found that females, whites, those aged 65-79, and those with non-spousal others, were significantly more likely to use one or more prescription drugs with addiction potential, controlling for health status and severity-of-illness. The significance and magnitude of several explanatory variables, including age, race, ethnicity, living arrangement, and health status, varied by therapeutic category. This paper provides an important first step in acknowledging the widespread use of abusable prescription drugs in elders, and provides a foundation for future research and practical solutions to preventing subsequent problem use of prescription drugs.

A pilot study of methylphenidate preference assessment in children diagnosed with attention-deficit/hyperactivity disorder

OBJECTIVE

The use of methylphenidate (MPH) in the treatment of attention-deficit/hyperactivity disorder (ADHD) is widely accepted; however, there is increased concern regarding its abuse potential. Few studies have examined the reinforcing effects of drugs in individuals receiving them for clinical purposes. This study attempts to assess MPH preference in children with ADHD using a choice procedure in order to explore the relationship among drug preference, clinical efficacy, and abuse potential.

METHODS

Participants were 5 children (10-14 years of age) receiving MPH for the treatment of ADHD. Reinforcing effects were assessed using a double-blind choice procedure, with six sampling sessions and six choice sessions. Participant-rated effects were measured using self-report questionnaires. Clinical effects were measured using direct observations and behavior ratings.

RESULTS

Differences between the number of MPH, Placebo, and Neither choices across participants were significant (chi2 = 9.6; p < 0.01). Three of five participants reliably chose MPH more often than placebo. MPH produced idiosyncratic patterns of participant-rated effects but failed to produce significant clinical effects.

CONCLUSIONS

These findings add to the literature on the reinforcing effects of MPH and are the first reported in a clinical sample of children. Further research exploring the role of clinical efficacy in MPH preference is warranted.

TPA023 [7-(1,1-dimethylethyl)-6-(2-ethyl-2H-1,2,4-triazol-3-ylmethoxy)-3-(2-fluorophenyl)-1,2,4-triazolo[4,3-b]pyridazine], an agonist selective for alpha2- and alpha3-containing GABAA receptors, is a nonsedating anxiolytic in rodents and primates

7-(1,1-Dimethylethyl)-6-(2-ethyl-2H-1,2,4-triazol-3-ylmethoxy)-3-(2-fluorophenyl)-1,2,4-triazolo[4,3-b]pyridazine (TPA023) is a triazolopyridazine that binds with equivalent high (subnanomolar) affinity to the benzodiazepine binding site of recombinant human GABA(A) receptors containing an alpha1, alpha2, alpha3, or alpha5 subunit but has partial agonist efficacy at the alpha2 and alpha3 subtypes and essentially antagonist efficacy at the alpha1 and alpha5 subtypes. In rats, TPA023 gave time- and dose-dependent occupancy after oral dosing, with 50% occupancy corresponding to a dose of 0.42 mg/kg. It has anxiolytic-like activity in unconditioned (elevated plus maze) and conditioned (fear-potentiated startle and conditioned suppression of drinking) rat models of anxiety with minimum effective doses (MED; 1-3 mg/kg) corresponding to 70 to 88% occupancy. However, there was no appreciable sedation in a response sensitivity (chain-pulling) assay at a dose of 30 mg/kg, resulting in 99% occupancy. Similarly, TPA023 was robustly anxiolytic in the squirrel monkey conditioned emotional response assay, with a MED of 0.3 mg/kg, but did not produce any sedation in a lever-pressing test of sedation even at 10 mg/kg. TPA023 produced no impairment in performance in the mouse Rotarod assay, and there was only a mild interaction with ethanol. In addition to anxiolytic-like efficacy, TPA023 had anticonvulsant activity in a mouse pentylenetetrazole seizure model. Finally, TPA023 did not cause precipitated withdrawal in mice treated for 7 days with the nonselective agonist triazolam, nor did N-methyl-beta-carboline-3-carboxamide (FG 7142) precipitate withdrawal in mice treated for 7 days with TPA023. In summary, the novel alpha2/alpha3-selective efficacy profile of TPA023 translates into a nonsedating anxiolytic profile that is distinct from nonselective agonists.

Correlates of nonmedical use of prescription benzodiazepine anxiolytics: results from a national survey of U.S. college students

This study examined the prevalence and correlates associated with the nonmedical use of prescription benzodiazepine anxiolytics among U.S. college students. This study analyzed data from a nationally representative sample of 10,904 randomly selected students attending 119, 4-year U.S. colleges in 2001. The lifetime prevalence of nonmedical prescription benzodiazepine anxiolytic use was 7.8%, past year prevalence was 4.5% and past month was 1.6%. Past year rates of nonmedical use of prescription anxiolytics ranged from zero percent at the lowest use schools to 20% at the highest use school. Multivariate regression analyses indicated nonmedical use was more likely to occur among college students who were White, had both male and female sex partners and reported higher rates of substance use and other risky behaviors. In addition, nonmedical use of prescription benzodiazepine anxiolytics was less likely to occur among college students who attended college in the North Central region of the U.S. or historically black colleges and universities (HBCUs). This study provides evidence that the nonmedical use of prescription benzodiazepine anxiolytics represents a problem on some college campuses and among certain subgroups of U.S. college students. These findings have important implications for developing prevention efforts aimed at reducing the nonmedical use of prescription benzodiazepine anxiolytics among college students while not hindering the effective clinical treatment for various anxiety disorders.

Mental disorders associated with benzodiazepine use among older primary care attenders--a regional survey

BACKGROUND

Benzodiazepines (BDZs) are among the most commonly prescribed drugs in the elderly and their use is often too prolonged according to current international guidelines.

METHODS

We investigated the pattern of use of BDZs among 65- to 84-year-old attenders at 40 Italian primary care practices who answered positively in a questionnaire on the use of anxiolytic/hypnotic drugs and successfully completed the PRIME-MD questionnaire. The survey lasted 6 months, from February to July 2001.

RESULTS

Of the 1,156 subjects who completed the PRIME-MD, 748 subjects were positive for at least one psychiatric diagnosis. A depressive disorder was present in 36.5% of all PRIME-MD completers and in about one-third of cases represented by major depression, whereas anxiety disorders, somatoform disorders and alcohol abuse accounted for 18.2%, 8.1% and 1.7% of all PRIME-MD completers, respectively. Most patients were first prescribed BDZs by their General Practitioners (GPs) for each diagnostic group. However, patients with pure anxiety started BDZ treatment during hospitalisation more often (19.7%) than patients with depressive disorders (13.7 %). Moreover, patients with comorbid anxiety and depressive disorders (CADD) were most likely to receive their first BDZ prescription from a psychiatrist (15.7 %). Sleep disturbances were present in at least 50% of cases (and up to 86 %) in each diagnostic group. About 75% of prescriptions concerned anxiolytic BDZ or medium/long-acting BDZ. Most patients with anxiety, CADD and depression used night-time BDZ (65.2%, 56.9 % and 60.5%, respectively). The prevalence of chronic use of BDZs was equally high in all categories of psychiatric disorder (about 90 % for each), showing that the vast majority of patients, irrespective of the diagnosis, had been using BDZs for years.

CONCLUSIONS

BDZs are widely prescribed for elderly people by their GPs, often for a considerable length of time. The evidence that many BDZ consumers suffer from a depressive or an anxiety disorder, or both, could be a starting point for encouraging a rational prescription in accordance with international guidelines.

A controlled study of the effects of state surveillance on indicators of problematic and non-problematic benzodiazepine use in a Medicaid population

OBJECTIVE

Benzodiazepines (BZs) are safe, effective drugs for treating anxiety, sleep, bipolar, and convulsive disorders, but concern is often expressed about their overuse and potential for abuse. We evaluated the effects of physician surveillance through a Triplicate Prescription Program (TPP) on problematic and non-problematic BZ use.

METHOD

This study uses interrupted time series analyses of BZ use in the New York (intervention) and New Jersey (control) Medicaid programs for 12 months before and 24 months after the New York BZ TPP. The regulation required NY physicians to order BZs on triplicate prescription forms with one copy forwarded by pharmacies to a state surveillance unit. Study participants were community-dwelling persons over age 18 continuously enrolled between January 1988 and December 1990 in New York (n = 125,837) or New Jersey Medicaid (n = 139,405).

RESULTS

During the baseline year, 20.2% of New York and 19.3% of New Jersey cohort members received at least one BZ prescription. After the TPP, there was a sudden, sustained reduction in BZ use of 54.8% (95% CI = [51.4%, 58.3%]) in New York with no changes in New Jersey. Significantly greater reductions were experienced by young women, and persons living in zip codes that were urban, predominantly Black, or with a high density of poor households. Increases in potential substitute medications were modest. At baseline, nearly 60% of BZ recipients had no evidence of potentially problematic use. Despite a somewhat greater likelihood of discontinuation of BZ therapy among those with potentially problematic use, the largest impact of the TPP was a substantially greater relative reduction in access to BZs among non-problematic users.

CONCLUSIONS

State-mandated physician surveillance dramatically reduces BZ use with limited substitution of alternative drugs, lowers rates of possible abuse, but may severely limit non-problematic BZ use.

Coriandrum sativum: evaluation of its anxiolytic effect in the elevated plus-maze

The clinical applications of benzodiazepines as anxiolytics are limited by their unwanted side effects. Therefore, the development of new pharmacological agents is well justified. Among medicinal plants, Coriandrum sativum L. has been recommended for relief of anxiety and insomnia in Iranian folk medicine. Nevertheless, no pharmacological studies have thus far evaluated its effects on central nervous system. Therefore, the aim of this study was to examine if the aqueous extract of Coriandrum sativum seed has anxiolytic effect in mice. Additionally, its effect on spontaneous activity and neuromuscular coordination were evaluated. The anxiolytic effect of aqueous extract (10, 25, 50, 100 mg/kg, i.p.) was examined in male albino mice using elevated plus-maze as an animal model of anxiety. The effects of the extract on spontaneous activity and neuromuscular coordination were assessed using Animex Activity Meter and rotarod, respectively. In the elevated plus-maze, aqueous extract at 100 mg/kg showed an anxiolytic effect by increasing the time spent on open arms and the percentage of open arm entries, compared to control group. Aqueous extract at 50, 100 and 500 mg/kg significantly reduced spontaneous activity and neuromuscular coordination, compared to control group. These results suggest that the aqueous extract of Coriandrum sativum seed has anxiolytic effect and may have potential sedative and muscle relaxant effects.

Enhanced heat loss and age-related hypersensitivity to diazepam

Whether elderly people suffer from age-related changes in pharmacokinetics and/or pharmacodynamics with administration of benzodiazepines is still a matter of controversy. We investigated the course of brain function and thermoregulation after oral administration of a standard benzodiazepine, diazepam (DZP), in 8 healthy young men (mean age, 19.8 years; range, 18 to 23 years) and 8 healthy middle-aged and older men (mean age, 60.9 years; range, 53 to 71 years). Placebo or DZP was administered in a single-blind crossover manner to the young men (placebo, 5-mg, 10-mg DZP) and to the older men (placebo, 5-mg DZP), and plasma DZP concentration, choice reaction time, proximal body temperature, and distal body temperature were monitored with high time resolution under a modified constant routine condition to exclude masking effects. Whereas there was no evidence of age-related alterations in pharmacokinetics between the 2 groups, the older subjects, in comparison to the young subjects, showed a more delayed choice reaction time in response to the same plasma DZP level, suggesting that hypersensitivity is related to increased age. DZP at 5 mg in the older subjects induced acute and transient hypothermia to the same degree as that induced by DZP at 10 mg in the young subjects. The distal-proximal body temperature gradient (difference between distal body temperature and proximal body temperature), an indicator of blood flow in distal skin regions, showed strong positive correlation with the delay in choice reaction time in both groups. These findings suggest that hypersensitivity to benzodiazepine in older persons may be due, at least in part, to age-related changes in thermoregulation, especially in the heat loss process.

Nefazodone in primary insomnia: an open pilot study

The present study is the first to investigate the effect of the antidepressant nefazodone on sleep in patients with primary (psychophysiological) insomnia. Following baseline assessment of sleep (polysomnography and subjective sleep parameters), 32 patients received initially 100 mg nefazodone in a single dose at bedtime; according to efficacy and tolerability, the dose could be increased up to 400 mg. Polysomnography and assessment of subjective sleep parameters were repeated after 4 weeks' administration. 12 patients dropped out, 11 of them due to lack of efficiency or intolerable side effects. In 20 patients who completed, the authors observed a lengthened sleep onset latency, decreases in stage 1 and slow wave sleep, and increases in stages 2 and REM under nefazodone. Subjective measures of sleep mirrored a clearer improvement: there was a significant reduction of the PSQI total score and all subscores except sleep latency. We suppose that the dose range chosen was too high for this patient population, thus accounting for the high proportion of dropouts and the partly unfavorable effects on objective sleep parameters. For a definite evaluation of the possible role of nefazodone in the treatment of primary (psychophysiological) insomnia, double-blind, placebo-controlled, randomized studies with lower doses are needed.

Assessing methylphenidate preference in ADHD patients using a choice procedure

RATIONALE

Methylphenidate (MPH) is widely used in the treatment of attention deficit hyperactivity disorder (ADHD) and is associated with positive clinical effects across a wide range of domains. Despite the clinical effectiveness of MPH, concern has arisen with respect to its abuse potential.

OBJECTIVES

To assess MPH preference in adults diagnosed with ADHD using a choice procedure and to evaluate the relationship among drug preference, therapeutic efficacy, and abuse potential in a clinical sample.

METHODS

Participants were ten volunteers (ages 18-22 years) with ADHD who were receiving MPH treatment. Preference was assessed using a double-blind choice procedure with four sampling sessions wherein subjects received either placebo or MPH and eight choice sessions when they chose either capsule or no capsules.

RESULTS

Overall, MPH was chosen significantly more often than placebo (chi2=52.5; P<0.001) and participants were equally separated into groups of those who chose MPH reliably (MPH choosers) and those who did not (MPH non-choosers). MPH decreased ADHD symptoms and resulted in lower ratings of stimulant effects among MPH choosers. MPH choosers also reported higher levels of baseline ADHD symptoms.

CONCLUSIONS

Despite higher preference of MPH than placebo in this clinical sample, other measures of abuse potential were not elevated, and MPH choosers were more symptomatic than non-choosers. As such, MPH preference in ADHD populations likely reflects therapeutic efficacy rather than abuse potential. Future work should examine MPH choice in diagnosed and non-diagnosed populations to further explore the role of clinical efficacy in the preference of this stimulant drug.