Effect of diazepam on ventilatory responses

Evaluation of safety and side effects in the process of anti-anxiety drug development *

As with other drugs it is necessary to look for changes induced by anxiolytics on vital signs, laboratory parameters and adverse events. In return, in a more specific way for anxiolytics, we will look at side effects at the central nervous system level with psychological and physiological battery tests. We will also assess the safety of use of anxiolytics in certain specific conditions, such as overdose or withdrawal and in certain populations such as the elderly, neonates and children. The assessment of safety and side effects, whatever the drug type studied, must come early in the developing process of a drug (phases I, II and III).

Benzodiazepines for the relief of breathlessness in advanced malignant and non-malignant diseases in adults

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 1, 2010, on 'Benzodiazepines for the relief of breathlessness in advanced malignant and non-malignant diseases in adults'. Breathlessness is one of the most common symptoms experienced in the advanced stages of malignant and non-malignant disease. Benzodiazepines are widely used for the relief of breathlessness in advanced diseases and are regularly recommended in the literature. At the time of the previously published Cochrane review, there was no evidence for a beneficial effect of benzodiazepines for the relief of breathlessness in people with advanced cancer and chronic obstructive pulmonary disease (COPD).

OBJECTIVES

The primary objective of this review was to determine the efficacy of benzodiazepines for the relief of breathlessness in people with advanced disease. Secondary objectives were to determine the efficacy of different benzodiazepines, different doses of benzodiazepines, different routes of application, adverse effects of benzodiazepines, and the efficacy in different disease groups.

SEARCH METHODS

This is an update of a review published in 2010. We searched 14 electronic databases up to September 2009 for the original review. We checked the reference lists of all relevant studies, key textbooks, reviews, and websites. For the update, we searched CENTRAL, MEDLINE, and EMBASE and registers of clinical trials for further ongoing or unpublished studies, up to August 2016. We contacted study investigators and experts in the field of palliative care asking for further studies, unpublished data, or study details when necessary.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and controlled clinical trials (CCTs) assessing the effect of benzodiazepines compared with placebo or active control in relieving breathlessness in people with advanced stages of cancer, chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF), motor neurone disease (MND), and idiopathic pulmonary fibrosis (IPF).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed identified titles and abstracts. Three review authors independently performed assessment of all potentially relevant studies (full text), data extraction, and assessment of methodological quality. We carried out meta-analysis where appropriate.

MAIN RESULTS

Overall, we identified eight studies for inclusion: seven in the previous review and an additional study for this update. We also identified two studies awaiting classification in this update. The studies were small (a maximum number of 101 participants) and comprised data from a total of 214 participants with advanced cancer or COPD, which we analysed. There was only one study of low risk of bias. Most of the studies had an unclear risk of bias due to lack of information on random sequence generation, concealment, and attrition. Analysis of all studies did not show a beneficial effect of benzodiazepines for the relief of breathlessness (the primary outcome) in people with advanced cancer and COPD (8 studies, 214 participants) compared to placebo, midazolam, morphine, or promethazine. Furthermore, we observed no statistically significant effect in the prevention of episodic breathlessness (breakthrough dyspnoea) in people with cancer (after 48 hours: risk ratio of 0.76 (95% CI 0.53 to 1.09; 2 studies, 108 participants)) compared to morphine. Sensitivity analyses demonstrated no statistically significant differences regarding type of benzodiazepine, dose, route and frequency of delivery, duration of treatment, or type of control. Benzodiazepines caused statistically significantly more adverse events, particularly drowsiness and somnolence, when compared to placebo (risk difference 0.74 (95% CI 0.37, 1.11); 3 studies, 38 participants). In contrast, two studies reported that morphine caused more adverse events than midazolam (RD -0.18 (95% CI -0.31, -0.04); 194 participants).

AUTHORS' CONCLUSIONS

Since the last version of this review, we have identified one new study for inclusion, but the conclusions remain unchanged. There is no evidence for or against benzodiazepines for the relief of breathlessness in people with advanced cancer and COPD. Benzodiazepines caused more drowsiness as an adverse effect compared to placebo, but less compared to morphine. Benzodiazepines may be considered as a second- or third-line treatment, when opioids and non-pharmacological measures have failed to control breathlessness. There is a need for well-conducted and adequately powered studies.

Flumazenil administration in poisoned pediatric patients

OBJECTIVE

The goal of this retrospective cohort study of pediatric patients exposed to flumazenil was to identify the frequency of seizures.

METHODS

Included patient were those aged 12 years or younger who received flumazenil, who had evidence of clinical poisoning as defined by an altered mental status, and who were reported to the California Poison Control System for the period 1999 to 2008. Data variables were age, sex, seizure, death, acute exposure to a benzodiazepine, drugs of exposure, long-term use of benzodiazepines, history of a seizure disorder, mental status before flumazenil administration, and poison center recommendation of flumazenil (yes/no).

RESULTS

Eighty-three patients were included. Forty-eight (58%) of this subset were female. Median age was 2 years (range, 3 months-12 years). Seventy (84%) patients were younger than 5 years. Of the 83 patients, 68 (82%) were allegedly exposed to a benzodiazepine; whereas, 12 (15%) had been allegedly exposed to a proconvulsant drug. No flumazenil-related seizures occurred (0% with 95% confidence interval, 0%-4%). The California Poison Control System recommended flumazenil use in 60 (72%) of the 83 cases, and 48 of these had been allegedly exposed to a benzodiazepine.

CONCLUSIONS

No flumazenil-associated seizures occurred among allegedly benzodiazepine- and non-benzodiazepine-poisoned pediatric patients aged 12 years or younger.

Benzodiazepines for the relief of breathlessness in advanced malignant and non-malignant diseases in adults

BACKGROUND

Breathlessness is one of the most common symptoms experienced in the advanced stages of malignant and non-malignant disease. Benzodiazepines are widely used for the relief of breathlessness in advanced diseases and are regularly recommended in the literature. However, the evidence for their use for this symptom is unclear.

OBJECTIVES

To determine the efficacy of benzodiazepines for the relief of breathlessness in patients with advanced disease.

SEARCH STRATEGY

We searched 14 electronic databases up to September 2009. We checked the reference lists of all relevant studies, key textbooks, reviews, and websites. We contacted investigators and specialists in palliative care for unpublished data.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and controlled clinical trials (CCTs) assessing the effect of benzodiazepines in relieving breathlessness in patients with advanced stages of cancer, chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF), motor neurone disease (MND), and idiopathic pulmonary fibrosis (IPF).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed identified titles and abstracts. Three independent review authors performed assessment of all potentially relevant studies (full text), data extraction, and assessment of methodological quality. We carried out meta-analysis where appropriate.

MAIN RESULTS

Seven studies were identified, including 200 analysed participants with advanced cancer and COPD. Analysis of all seven studies (including a meta-analysis of six out of seven studies) did not show a beneficial effect of benzodiazepines for the relief of breathlessness in patients with advanced cancer and COPD. Furthermore, no significant effect could be observed in the prevention of breakthrough dyspnoea in cancer patients. Sensitivity analysis demonstrated no significant differences regarding type of benzodiazepine, dose, route and frequency of delivery, duration of treatment, or type of control.

AUTHORS' CONCLUSIONS

There is no evidence for a beneficial effect of benzodiazepines for the relief of breathlessness in patients with advanced cancer and COPD. There is a slight but non-significant trend towards a beneficial effect but the overall effect size is small. Benzodiazepines caused more drowsiness as an adverse effect compared to placebo, but less compared to morphine. These results justify considering benzodiazepines as a second or third-line treatment within an individual therapeutic trial, when opioids and non-pharmacological measures have failed to control breathlessness. Although a few good quality studies were included in this review, there is still a further need for well-conducted and adequately powered studies.

Sleep at High Altitude

New arrivals to altitude commonly experience poor-quality sleep. These complaints are associated with increased fragmentation of sleep by frequent brief arousals, which are in turn linked to periodic breathing. Changes in sleep architecture include a shift toward lighter sleep stages, with marked decrements in slow-wave sleep and with variable decreases in rapid eye movement (REM) sleep. Respiratory periodicity at altitude reflects alternating respiratory stimulation by hypoxia and subsequent inhibition by hyperventilation-induced hypocapnia. Increased hypoxic ventilatory responsiveness and loss of regularization of breathing during sleep contribute to the occurrence of periodicity. Interventions that improve sleep quality at high altitude include acetazolamide and benzodiazepines.

Effect of diazepam on survival of the immature pig in a confined atmosphere

Diazepam is known to prolong survival in an atmosphere containing 5% oxygen, and to reduce cerebral metabolic rate and cerebral perfusion. It also depresses the arousal response to hypoxia and protects the optic nerve from anoxia. We hypothesised that diazepam might extend survival in a confined atmosphere with a limited amount of oxygen. Pigs consumed the oxygen in a sealed chamber until they reached the terminal state. The experimental pigs (n = 6) were sedated with diazepam 0.3 mg/kg i.v. and were compared with a control group (n = 5). We measured blood pressure, inspired O2 and CO2, minute ventilation, ECG, ambient and body temperatures, and PO2, PCO2, O2 content and pH in arterial and venous blood. In the diazepam-treated pigs, oxygen consumption was reduced in the hypoxic range (PIO2 below 60 torr) compared with the control pigs. Diazepam prevented the elevated hypoxic cardiac output found in the control pigs. There were almost no differences between the diazepam and control groups in the other parameters measured in the course of the exposure and in the terminal state. Terminal PIO2, PaO2, and PvO2 were 36.9 +/- 5.6, 27.9 +/- 8.6, 14.3 +/- 2.0 torr, and 36.9 +/- 5.7, 23.7 +/- 7.3, 15.7 +/- 7.6 torr in the diazepam and control groups, respectively. The survival time was 220 +/- 51 and 255 +/- 50 min in diazepam and control pigs, respectively. In spite of its anticonvulsant effect and the fact that it protects CNS white matter from anoxia, prolongs anoxic survival and eliminates the high oxygen demand in hypoxic arousal, diazepam failed to extend hypoxic survival in a confined atmosphere to a lower PIO2. However, diazepam had no deleterious effect on survival, and may therefore be used to ease stressful hypoxic conditions.

The palliation of dyspnea in terminal disease

Dyspnea is a complex subjective experience that is common in terminal illness. Patients may present at any time during the course of their illness, although prevalence increases with disease progression. Dyspnea has physical, psychological, social and spiritual components; without recognizing how each of these contributes to the total suffering of dyspnea, management is unlikely to be successful. The management of dyspnea involves both pharmacological and non-pharmacological treatment. The main pharmacological palliative treatments are oxygen, opioids, and benzodiazepines, but the evidence to support these treatments is limited. More research is urgently needed to establish the efficacy of current treatments and to identify new ones.

Influence of the quality of nursing on the duration of weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease

OBJECTIVE

To evaluate the influence of nursing on the duration of weaning from mechanical ventilation in patients with chronic obstructive pulmonary disease.

DESIGN

Data were collected prospectively over a 1-yr period (study year) and compared with previously collected prospective data recorded in our chronic obstructive pulmonary disease database during a 5-yr period.

SETTING

The medical intensive care unit (ICU) of a university hospital.

PATIENTS

Eighty-seven patients with chronic obstructive pulmonary disease. Fifteen patients had chronic obstructive pulmonary disease that required mechanical ventilation for acute exacerbation of their disease (study year), and 72 were patients with chronic obstructive pulmonary disease from the previously collected data.

INTERVENTIONS

The ICU course (duration of mechanical ventilation, mortality) was recorded, as well as several respiratory parameters (pulmonary function tests and arterial blood gases in stable conditions, and nutritional status), and they were compared with an "index of nursing."

MEASUREMENTS AND MAIN RESULTS

We developed an "index of nursing", comparing the effective workforce of the nurses (number and qualifications) with the ideal workforce required by the number of patients and the severity of their diseases. A value of 1.0 represented a perfect match between the needed and the effectively present nurses, whereas a lesser value signified a diminished available workforce. This index was compared with the complications and duration of weaning from mechanical ventilation. During the first 5 yrs, the duration of mechanical ventilation increased progressively from 7.3 +/- 8.0 to 38.2 +/- 25.8 days (p = .006). A significant inverse correlation between the duration of mechanical ventilation and the nursing index (p = .025) was found. In the sixth comparative year, the number of nurses increased (nursing index = 1.05) and the duration of mechanical ventilation decreased to 9.9 +/- 13 days (p < .001, yr 5 vs. yr 6).

CONCLUSIONS

The quality of nursing appears to be a measurable and critical factor in the weaning from mechanical ventilation of patients with chronic obstructive pulmonary disease. Below a threshold in the available workforce of ICU nurses, the weaning duration of patients with chronic obstructive pulmonary disease increases dramatically. Therefore, very close attention should be given to the education and number of ICU nurses.

Psychotropic drug use in the medically ill. Part II

Underlying medical illness and drug interactions may make the use of psychotropic agents problematic in some physically ill patients. This overview, published in two parts, discusses six major classes of psychotropic medications (cyclic antidepressants, monoamine oxidase inhibitors, benzodiazepines, neuroleptics, lithium, psychostimulants, and carbamazepine) and examines their use in the setting of specific types of medical illnesses (e.g., cardiovascular, pulmonary, hepatic, and renal disease). Practical considerations in using psychotropic medications in medical-surgical patients--particularly those who are elderly or medically debilitated--will receive special emphasis.

Psychotropic drug use in the medically ill: Part I

Underlying medical illness and drug interactions may make the use of psychotropic agents in some physically ill patients problematic. This overview, published in two parts, discusses six major classes of psychotropic medications (cyclic antidepressants, monoamine oxidase inhibitors, benzodiazepines, neuroleptics, lithium, psychostimulants, and carbamazepine) and examines their use in the setting of specific types of medical illnesses (e.g., cardiovascular, pulmonary, hepatic, and renal disease). Practical considerations in using psychotropic medications in medical-surgical patients, particularly those who are elderly or medically debilitated, receive special emphasis. In part I, the use of cyclic antidepressants, monoamine oxidase inhibitors, benzodiazepines, and buspirone are discussed.

Effect of alprazolam on exercise and dyspnea in patients with chronic obstructive pulmonary disease

To evaluate the efficacy of a mild anxiolytic, alprazolam, in relieving dyspnea, we conducted a randomized, placebo-controlled double-blind study on patients with chronic obstructive lung disease. Twenty-four patients had alprazolam (0.5 mg bid) or placebo administered for one week, followed by placebo for one week, then either placebo or alprazolam for the third week. Assessment tests were performed at the outset, end of the first and second weeks, and finally end of the third week. The parameters measured were: pulmonary function, exercise testing on a bicycle ergometer, and the distance covered in a 12 minute walk. Subjective sensations of dyspnea at rest and during guarded exercise, as well as subjective feelings of calmness or anxiety were also recorded. There was no difference in mechanical lung function, but the PO2 tended to decrease and PCO2 to increase after alprazolam administration. The maximum exercise level attained and the distance covered in the 12 minute walk was unchanged. The subjective perception of dyspnea was the same before and after alprazolam, at rest and during exercise. We conclude that alprazolam is not effective in relieving exercise dyspnea in patients with obstructive lung disease.

The intensive care unit syndrome: causes, treatment, and prevention

The psychological assessment and management of the critically ill patient is often overlooked as a part of the patient care plan. The intensive care unit (ICU) syndrome is a type of organic brain syndrome manifested by a variety of psychological reactions, including fear, anxiety, depression, hallucinations, and delirium. Causes, treatment modalities, and a multidisciplinary approach to preventing the ICU syndrome are presented. Causative factors that should be assessed in the psychological evaluation of ICU patients include: (1) preadmission history; (2) past ability to adapt to stress; (3) past and current medications; (4) current clinical status; and (5) environmental factors. The treatment of the ICU syndrome includes: (1) the correction or elimination of causative factors; (2) the appropriate choice, dose, and route of administration of anxiolytic and antipsychotic agents; (3) reduction or elimination of sources of environmental stress; and (4) frequent patient and family communication. Finally, the prevention of the ICU syndrome through the involvement of physicians, nurses, and pharmacists is stressed.

The effect of chlormethiazole on the hypoxic drive to breathing in normal man

We have studied the effects of chlormethiazole infusion on the ventilatory response to progressive isocapnic hypoxia in seven healthy volunteers, during both normocapnia and induced hypercapnia. The dose of chlormethiazole was such that it produced the same degree of hypnosis as would be expected from oral administration of two capsules each containing 192 mg of base in arachis oil. Ventilation did not change significantly during chlormethiazole administration. The ventilatory response to hypoxia was unaffected by chlormethiazole during normocapnia and was enhanced during hypercapnia. In these subjects, giving chlormethiazole intravenously was not associated with depression of the resting ventilation nor the hypoxia ventilatory response.

Intravenous benzodiazepines as anaesthetic agents: pharmacokinetics and clinical consequences

Despite extensive and numerous pharmacokinetic studies on benzodiazepines, the published pharmacokinetic data do not adequately explain the clinical differences found between different benzodiazepine derivatives after intravenous administration. Especially, correlations between initial drug responses and distributional changes of the benzodiazepines are limited. However, during the elimination phase some relationships exist between the kinetic and dynamic phenomena. Age, sex, diseases and concomitantly given drugs cause clinically important alterations in the pharmacokinetics of benzodiazepines. Generally these anxiolytics and sedatives should be considered as adjuvants to general anaesthesia, but not primarily as routine induction agents. The major reasons for this limitation are a high variability in drug response, a relatively slow onset of action and long-lasting residual effects. However, benzodiazepines have many important advantages (see Table 5) when used as intravenous inducing agents of general anaesthesia.

The pathophysiology of acute high-altitude illness

Complex physiologic responses occur as nonacclimatized lowland dwellers ascend above 10,000 feet, with a resulting partial pressure of arterial oxygen of less than 60 mm Hg. There are marked hemodynamic changes and shifts in body fluids that may result in organ dysfunction. The suspected pathogenesis of these acute hypobaric hypoxic-induced illnesses is discussed. Cerebral dysfunction may present as acute mountain sickness or high-altitude cerebral edema. Usually asymptomatic high-altitude retinal hemorrhage and noncardiogenic high-altitude pulmonary edema also are described. All of these illnesses apparently represent a spectrum of pathologic states initiated by an exaggerated vascular response to hypoxia. With the exception of retinopathy, high-altitude illness can be prevented by slow ascent. Early recognition of cerebral or pulmonary edema and immediate descent will prevent serious consequences of nonacclimatized persons who are acutely exposed to hypobaric environments.

Systemic complications with intravenous diazepam

There are few published reports of complications following intravenous diazepam administration. However, more than 200 cases were reported to the United States Department of Health, Education and Welfare during a 7-year period. The systemic complications have been categorized by the authors, and common contributing factors are emphasized. The information obtained from these reports provides further knowledge of both the avoidance and the treatment of such complications and emphasizes the importance of reporting the adverse effects of any drug to a central body.