Hypnotics and the control of breathing: a review

Apneas of Heart Failure and Phenotype-Guided Treatments: Part One: OSA

Sleep-disordered breathing (SDB), including OSA and central sleep apnea, is highly prevalent in patients with heart failure (HF). Multiple studies have reported this high prevalence in asymptomatic as well as symptomatic patients with reduced left ventricular ejection fraction (HFrEF), as well as in those with HF with preserved ejection fraction. The acute pathobiologic consequences of OSA, including exaggerated sympathetic activity, oxidative stress, and inflammation, eventually could lead to progressive left ventricular dysfunction, repeated hospitalization, and excessive mortality. Large numbers of observational studies and a few small randomized controlled trials have shown improvement in various cardiovascular consequences of SDB with treatment. There are no long-term randomized controlled trials to show improved survival of patients with HF and treatment of OSA. One trial of positive airway pressure treatment of OSA included patients with HF and showed no improvement in clinical outcomes. However, any conclusions derived from this trial must take into account several important pitfalls that have been extensively discussed in the literature. With the role of positive airway pressure as the sole therapy for SDB in HF increasingly questioned, a critical examination of long-accepted concepts in this field is needed. The objective of this review was to incorporate recent advances in the field into a phenotype-based approach to the management of OSA in HF.

Oral Low-Dose Midazolam as Premedication for Intraocular Surgery in Retrobulbar Anesthesia: Cardiovascular Effects and Relief of Perioperative Anxiety

The aim was to investigate the efficacy and practicability of oral low-dose premedication with 3.75 mg midazolam (1/2 tablet Dormicum 7.5 mg) for selective intraocular surgery with retrobulbar anesthesia. Forty-six ASA II-III patients were randomly assigned to either group I: midazolam (n = 24) or group II: placebo (n = 22). Sedation was objectively quantified with a scale derived from the Glasgow-Coma-Scale and a verbal self-rating scale. Trait-anxiety was studied with the State-Trait Inventory by Spielberger, perioperative situative anxiety with the Erlanger Anxiety Scale. Cardiovascular variables and oxygenation were automatically monitored. Midazolam produced significant and sufficient sedation and significant anxiolysis. Systolic, diastolic and mean blood pressure were moderately but significantly, reduced. The effect on diastolic pressure was more pronounced. There was no effect on heart-rate. Oxygenation at all times remained well above 90% SpO2. In conclusion low-dose oral midazolam proved to be a single and effective premedication before intraocular surgery under local anesthesia.

Pharmacology of ramelteon, a selective MT1/MT2 receptor agonist: a novel therapeutic drug for sleep disorders

An estimated one-third of the general population is affected by insomnia, and this number is increasing due to more stressful working conditions and the progressive aging of society. However, current treatment of insomnia with hypnotics, gamma-aminobutyric acid A (GABA(A)) receptor modulators, induces various side effects, including cognitive impairment, motor disturbance, dependence, tolerance, hangover, and rebound insomnia. Ramelteon (Rozerem; Takeda Pharmaceutical Company Limited, Osaka, Japan) is an orally active, highly selective melatonin MT(1)/MT(2) receptor agonist. Unlike the sedative hypnotics that target GABA(A) receptor complexes, ramelteon is a chronohypnotic that acts on the melatonin MT(1) and MT(2) receptors, which are primarily located in the suprachiasmatic nucleus, the body's "master clock." As such, ramelteon possesses the first new therapeutic mechanism of action for a prescription insomnia medication in over three decades. Ramelteon has demonstrated sleep-promoting effects in clinical trials, and coupled with its favorable safety profile and lack of abuse potential or dependence, this chronohypnotic provides an important treatment option for insomnia.

Non-benzodiazepines for the treatment of insomnia

Benzodiazepine hypnotics, the mainstay of pharmacological treatment for insomnia, have been associated with altered sleep architecture, psychomotor and memory impairment, rebound insomnia, withdrawal effects, tolerance, dependence, abuse potential and respiratory depression. Non-benzodiazepines, such as zolpidem, zopiclone and zaleplon, demonstrate hypnotic efficacy similar to that of benzodiazepines along with excellent safety profiles. Non-benzodiazepines generally cause less disruption of normal sleep architecture than benzodiazepines. Psychomotor and memory impairment may be less problematic with non-benzodiazepines, especially when compared to longer-acting benzodiazepines. Rebound insomnia and withdrawal symptoms occur infrequently upon discontinuation of non-benzodiazepines and may be less common and milder than those seen upon discontinuation of some benzodiazepines. For the long-term treatment of insomnia, which is generally not recommended, zolpidem and zopiclone are particularly good options because they do not develop tolerance rapidly and have a low abuse potential. Limited data indicate that zaleplon has low tolerance and abuse potential, although further experience is needed to determine its long-term efficacy and safety profile. Since non-benzodiazepines produce minimal respiratory depression, they may be safer than benzodiazepines in patients with respiratory disorders. The choice of which hypnotic to use should be based on the patient's primary sleep complaint, health history, adverse effects and cost.

The use of psychotropics in the medically ill

Underlying medical illness may present a challenge when prescribing psychotropic medications. Disease-related changes in pharmacokinetics and pharmacodynamics, as well as vulnerability to side effects, polypharmacy, and potential drug interactions are all important considerations. Successful treatment of psychiatric disorders may have a beneficial impact on medical morbidity and mortality, as well as quality of life. This article reviews the relevant considerations when using psychotropic medications in six major medical populations (cardiac, cerebral vascular, pulmonary, liver, renal, and seizure disorders).

Effects of repeated administration of zolpidem on sleep, diurnal and nocturnal respiratory function, vigilance, and physical performance in patients with COPD

STUDY OBJECTIVE

To assess the effects of repeated 10-mg oral doses of zolpidem on diurnal and nocturnal respiratory function, as well as on diurnal vigilance and physical performance in COPD patients with disordered sleep.

DESIGN

Prospective single-blind placebo-controlled clinical study.

SETTING

Outpatients of a respiratory medicine department.

PATIENTS AND METHODS

Patients with stable COPD were enrolled for 10 days (D0 to D10), ie, 9 consecutive nights (N1 to N9). They received placebo on N1 and N9 and zolpidem, 10 mg, from N2 to N8.

MEASUREMENTS

The following parameters were measured: nocturnal polysomnographic recordings with respiratory signals and arterial blood gas values on retiring and awakening on N0, N1, N2, N8, and N9; subjective evaluation of the quality of sleep and of diurnal vigilance by visual analog scales every day from D0 to D10; pulmonary function test, central control of breathing, and walking test on D0 and D9; biological laboratory tests and theophylline level on D0 and D8.

RESULTS

Ten COPD patients (PaO2 = 72.7 +/- 7.6 mm Hg; PaCO2 = 47.7 +/- 5.4 mm Hg; FEV1 = 0.84 +/- 0.3 L; FEV1/vital capacity = 42.5 +/- 12.3%), 56.8 +/- 8.3 years old, were studied. Compared with placebo, no significant change was found for the various sleep architecture parameters, except an increase in the duration of stage 2 during the D8/N8 night (p < 0.05). In contrast, the autoevaluation score for the quality of sleep was significantly improved during the D6/N6 night relative to that with placebo (p < 0.05), with no change in the other subjective criteria. No variable of the nocturnal respiratory parameters, pulmonary function test, central control of breathing, and physical performance was altered by zolpidem. Arterial blood gas values on awakening were not altered. Clinical and biological tolerance of zolpidem was correct with no significant variation of the theophylline level.

CONCLUSION

This study shows that repeated 10-mg oral doses of zolpidem during 8 days does not impair nocturnal respiratory and sleep architecture parameters or diurnal pulmonary function tests, central control of breathing, and physical performances in patients with stable COPD.

Benzodiazepine Utilization Review for Inpatients at a Tertiary Medical Center in Taiwan

Objectives:

To examine benzodiazepine prescribing patterns by physicians for inpatients relative to indications and drug characteristics in a tertiary medical center.

Design:

Prescription pattern analysis was done by checking computer-based pharmacy records. Benzodiazepine utilization was evaluated through retrospective chart review.

Results:

A total of 2,195 inpatients were surveyed, of whom 945 were given benzodiazepines. Of these, 827 charts were available for review. The mean number of prescriptions written for benzodiazepines was 1.62 per patient. Of the benzodiazepines available, triazolam was most frequently prescribed. The use of benzodiazepines ranged from 38.7% in the internal medicine ward to 85.1% in the oncology ward. We found that 60% of prescriptions were appropriate, 24.9% were prescribed without documentation, and 15.1% were used inappropriately.

Conclusions:

Proper prescribing of benzodiazepines is essential in the management of the symptoms of mental illness. From both a diagnostic and treatment perspective, more education efforts are needed in the investigation, documentation, and treatment of mental illness symptoms.

Drugs and brain death

Brain death protocols facilitate early recognition of death in patients on life support systems. When the clinical situation has deteriorated to a level where brain death is to be considered, it is essential that the effects of drugs be excluded. Most centrally acting drugs depress respiration and would be expected to affect apnoea testing of brain stem function. However, the pharmacodynamic and pharmacokinetic properties of drugs are altered when patients are critically ill, so projections made from data derived from less ill patients or normal volunteers are inappropriate. The entry of drugs into the brain is also altered in some disease states, but there are few data relating to the effects of central depressant drugs in the situation of a disrupted blood-brain barrier or brain damage. Drug screens can assist in determining whether drugs are present, but correct interpretation of the results depends on close liaison between the clinical and laboratory staff. It is in the patient's interests to avoid termination of life support if any centrally active drug is present, unless there are other categorical factors consistent with irreversible brain death, such as demonstrated lack of cerebral blood flow.

Pharmacotherapy of insomnia: practice and prospects

Insomnia is a complex complaint which is often multifactorial in origin. Pharmacotherapy can only be an adjunct in the treatment of insomnia and hypnotics should be given on an intermittent basis for short periods of time. An overview is presented of the currently available hypnotics, of which benzodiazepines are still the most widely prescribed. New drugs which bind to specific receptor subtypes or which are partial benzodiazepine receptor agonists might overcome the disadvantages associated with chronic benzodiazepine use, but more long-term investigations are needed.

Guidelines for the rational use of benzodiazepines. When and what to use

The main actions of benzodiazepines (hypnotic, anxiolytic, anticonvulsant, myorelaxant and amnesic) confer a therapeutic value in a wide range of conditions. Rational use requires consideration of the large differences in potency and elimination rates between different benzodiazepines, as well as the requirements of individual patients. As hypnotics, benzodiazepines are mainly indicated for transient or short term insomnia, for which prescriptions should if possible be limited to a few days, occasional or intermittent use, or courses not exceeding 2 weeks. Temazepam, loprazolam and lormetazepam, which have a medium duration of action are suitable. Diazepam is also effective in single or intermittent dosage. Potent, short-acting benzodiazepines such as triazolam appear to carry greater risks of adverse effects. As anxiolytics, benzodiazepines should generally be used in conjunction with other measures (psychological treatments, antidepressants, other drugs) although such measures have a slower onset of action. Indications for benzodiazepines include acute stress reactions, episodic anxiety, fluctuations in generalised anxiety, and as initial treatment for severe panic and agoraphobia. Diazepam is usually the drug of choice, given in single doses, very short (1 to 7 days) or short (2 to 4 weeks) courses, and only rarely for longer term treatment. Alprazolam has been widely used, particularly in the US, but is not recommended in the UK, especially for long term use. Benzodiazepines also have uses in epilepsy (diazepam, clonazepam, clobazam), anaesthesia (midazolam), some motor disorders and occasionally in acute psychoses. The major clinical advantages of benzodiazepines are high efficacy, rapid onset of action and low toxicity. Adverse effects include psychomotor impairment, especially in the elderly, and occasionally paradoxical excitement. With long term use, tolerance, dependence and withdrawal effects can become major disadvantages. Unwanted effects can largely be prevented by keeping dosages minimal and courses short (ideally 4 weeks maximum), and by careful patient selection. Long term prescription is occasionally required for certain patients.

Effects of zolpidem, codeine phosphate and placebo on respiration. A double-blind, crossover study in volunteers

The effects of zolpidem, codeine phosphate and placebo on respiration were evaluated in a double-blind, randomised, crossover study involving 12 healthy men. Single oral doses of zolpidem 10 or 20 mg, codeine phosphate 60 mg or placebo were administered in the morning. Each treatment was separated by a washout period of at least 72 h. Ventilatory responses to carbon dioxide and mouth occlusion pressure, measured 1 h before and at 1 and 3 h after doses, were not significantly affected by either zolpidem dose; however, codeine phosphate produced a small but significant respiratory suppressant effect at 3 h. Mean inspiratory flow was noninvasively assessed using respiratory inductive plethysmography 1 h predose and at 1 to 5 h postdose. No significant change in mean inspiratory flow was noted after zolpidem 10 mg. Two hours after administration of zolpidem 20 mg, mean inspiratory flow was significantly lower than after placebo, possibly related to some individuals falling asleep during data collection. All volunteers reported adverse events; the most common were slurred speech (in 1 after 10 mg and in 5 after 20 mg of zolpidem), dizziness (in 4 after both 10 mg and 20 mg of zolpidem) and diplopia/blurred vision (in 4 after 20 mg of zolpidem). Zolpidem appears to be well tolerated, with no respiratory suppression up to doses of 10 mg and minimal suppression of mean inspiratory drive at doses of 20 mg.

Breath-holding in panic disorder

In earlier studies, it was found that exogenous carbon dioxide administration provoked high anxiety in panic disorder (PD) patients, whereas healthy normals and patients suffering from other anxiety disorders were hardly affected. Breath-holding provides a simple method to induce endogenous CO2 accumulation. Fourteen PD patients, 14 patients suffering from other anxiety disorders, and 14 healthy controls were asked to hold their breath as long as possible. Apnea times appeared to be longer in the normal control group than in the other two groups. Using a one-tailed t test, a trend for a difference was found between the PD subjects and other anxiety patients, the PD patients having slightly lower values. No differences were found with respect to increase in anxiety during breath-holding or the ratio of apnea times before and after hyperventilation.

A comparison of the effects of zolpidem and placebo on respiration and oxygen saturation during sleep in the healthy elderly

1. In a double-blind placebo controlled trial, zolpidem 10 mg, a new imidazopyridine hypnotic drug, was administered to 10 elderly female patients and placebo to 11, all recovering from hip and knee replacement surgery. Respiratory monitoring with an inductance plethysmograph and pulse oximeter showed that treatment over a 4 night period did not increase significantly the severity, frequency or duration of hypoxaemic episodes leading to SaO2 less than 90% or less than 85% when compared with placebo. Confidence intervals (corrected for baseline differences) for the median differences between the two groups on night 7, the fourth night of treatment, were from -1.85 to 0.480 and from -1.07 to 0 respectively for the frequency, and from -0.76 to 0.15 and -0.5 to 0 for the duration of the hypoxaemic episodes. The incidence of sleep related respiratory disturbances was not significantly increased compared with placebo on any night. 2. Respiratory monitoring using a simple inductance plethysmograph and pulse oximeter is acceptable to patients and staff. 3. The evaluation of all hypnotic and sedative drugs should include their effects on respiration during sleep.

Benzodiazepines, breathing, and sleep

The benzodiazepines are sedative hypnotic drugs, i.e., central nervous system depressant drugs, that may adversely affect the control of ventilation during sleep. Prescription of these drugs may worsen sleep-related breathing disorders, especially in patients with chronic obstructive pulmonary disease or cardiac failure. The most frequent users of sedative hypnotics are the polymorbid elderly with a secondary complaint of insomnia. Although the benzodiazepines may reduce sleep fragmentation, their long-term use may also cause health problems, such as complete obstructive sleep apnea in heavy snorers or short repetitive central sleep apnea in patients with recent myocardial infarction. Since drugs of this class vary in their effects, it is crucial to note the action of a given benzodiazepine on the control of vital functions during sleep.

Safety of estazolam. The United States clinical experience

The safety profile of estazolam, a new triazolobenzodiazepine hypnotic medication, has been developed in 1,320 normal volunteers and patients with insomnia. No clinically significant effects of estazolam on vital signs or laboratory values were detected. Drug-specific adverse effects such as somnolence, dizziness, hypokinesia, and abnormal coordination occurred, but these are expected extensions of benzodiazepine pharmacologic activity. No consistent effects on psychomotor performance, including memory, were seen at the recommended hypnotic doses in insomniac subjects. These data, combined with the evidence for hypnotic activity, indicate that estazolam is a safe and effective treatment for insomnia.

The effects of nitrazepam and flunitrazepam on oxygen desaturation during sleep in patients with stable hypoxemic nonhypercapnic COPD

Serious respiratory depression has been described in COPD patients receiving hypnotics during acute exacerbations. There are few studies quantifying the effects of hypnotics on oxygenation during sleep in patients with stable hypoxemic COPD. In this study, the effects of single therapeutic doses of nitrazepam and flunitrazepam on SaO2, apneas during sleep and other sleep variables were measured in 14 COPD patients. All patients used theophylline. Sleep-induced decrease in mean SaO2 was 1.3 percent after placebo, 1.4 percent after nitrazepam and 1.9 percent after flunitrazepam (no significant differences). Sleep apneas were not more common or longer after nitrazepam or flunitrazepam, but sleep quality seemed to improve. It is concluded that oxygenation during sleep in these nonobese patients with stable hypoxemic nonhypercapnic COPD, all on maintenance theophylline therapy, was affected very little by single therapeutic doses of nitrazepam or flunitrazepam.

Effects of diazepam and chlormethiazole on ventilatory control in normal subjects

We have studied the effects of chlormethiazole and diazepam given orally on the ventilatory and mouth occlusion pressure (P0.1) responses to CO2 in a placebo controlled study in 10 healthy volunteers. Diazepam 10 mg produced a significant reduction in both the ventilatory and P0.1 responses to CO2, and this was not associated with any effect on respiratory muscle power. Chlormethiazole 250 mg produced less drowsiness than diazepam 10 mg. Therefore in a subsequent study chlormethiazole 500 mg was compared with placebo. Chlormethiazole in either dose had no effect on CO2 responses or on maximum static respiratory pressures. We conclude that diazepam has a direct depressant effect on chemoreceptors and its effects on indices of ventilatory control are not due to impaired muscle function; chlormethiazole in the doses used has no such effects despite producing drowsiness.