Biomedical subjects
R L Manfredi
Publications and source records attributed to R L Manfredi.
Next-day memory impairment with triazolam use.
The prevalence, rate, and degree of memory impairment for next-day activities during a short, intermittent course of bedtime doses of triazolam, temazepam, and placebo were assessed in a double-blind parallel-group study. 5 of the 6 subjects in the triazolam group reported at least one episode of next-day memory impairment/amnesia, with a total of 12 episodes being reported for the 30 subject-drug nights (a rate of 40%). In the temazepam group there were no such episodes of memory impairment. Immediate and delayed recall were also tested and related to whether active drug or placebo had been taken the night before. Impairment of delayed recall was significantly and several times greater than that in the temazepam or placebo groups. Next-day memory impairment/amnesia after a bedtime dose of triazolam tended to increase with continued or intermittent drug use. Cognitive impairments associated with triazolam probably represent a spectrum of organic brain dysfunction, with memory impairment/amnesia and confusion being the commonest, and milder manifestations and hallucinations and delusions the more severe and less common, features.
Effects of lovastatin and pravastatin on sleep efficiency and sleep stages.
The effects on sleep of two 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (40 mg lovastatin and 40 mg pravastatin) were evaluated in 12 normal subjects in a double-blind placebo-controlled sleep laboratory study. Subjects were randomly assigned to each of two parallel groups (lovastatin and pravastatin). Each parallel-group protocol consisted of 22 consecutive nights including 4 placebo-baseline nights, 2 weeks of drug administration, and 4 placebo-withdrawal nights. Lovastatin did not disturb sleep initially (nights 5 through 7) but, with continued administration (nights 16 through 18), it significantly and markedly increased wake time after sleep onset and stage 1 sleep compared with baseline. By contrast, pravastatin was not associated with sleep disturbance either initially or with continued use. Neither drug caused any sleep disturbance after withdrawal. Lovastatin's sleep disturbing effects with continued administration are attributed to its high degree of lipophilicity in contrast with the hydrophilicity of pravastatin.
Rebound insomnia after only brief and intermittent use of rapidly eliminated benzodiazepines.
In three parallel groups, brief and intermittent administration and withdrawal of triazolam, 0.5 mg, temazepam, 30 mg, and placebo were assessed in a 12-night sleep laboratory study of 18 subjects with insomnia. With this intermittent schedule both drugs improved sleep, with about one-third reduction in total wake time; this reduction was significant for temazepam but not for triazolam. Even though the periods of drug administration were quite brief, withdrawal of triazolam consistently produced rebound insomnia, with increases in total wake time above baseline of 61% and 51%, respectively, for the first night of each withdrawal period. With temazepam this effect was more variable, with total wake time increased only with the second withdrawal period (39%). Thus these findings indicate that even under conditions of brief, intermittent use and withdrawal, triazolam and, to a lesser degree, temazepam produce rebound insomnia after abrupt withdrawal, thereby predisposing to drug-taking behavior and increasing the potential for drug dependence.
Buspirone: sedative or stimulant effect?
OBJECTIVE: The primary objectives of this study were to evaluate the effects of initial and continued administration of buspirone on sleep induction and maintenance and sleep stage parameters, to determine the presence or absence of any drug-induced side effects, and to ascertain the presence or absence of sleep disturbances following abrupt withdrawal of the drug. METHOD: Six insomniac subjects who had chronic complaints of difficulty falling asleep and/or staying asleep and who were in good physical health, were not suffering from any major mental disorders, and had not used any medication for at least the last month participated in a 16-night sleep laboratory protocol. The protocol consisted of 4 placebo-baseline nights, 7 nights on which buspirone, 10 mg at bedtime, was administered, and 5 placebo-withdrawal nights. RESULTS: Wake time after sleep onset increased moderately during the first 3 nights of drug administration (there was a marked and significant increase on the first night) and increased by lesser degrees with continued drug administration. Overall, reports of side effects were infrequent. Following drug termination, there was a delayed and mild increase in sleep difficulty above baseline. CONCLUSIONS: These data not only confirm that buspirone lacks sedative effects but also suggest that the drug may have stimulant properties. Further, these findings suggest that buspirone has limited usefulness in anxious patients with concomitant sleep difficulties.
Clonazepam: sleep laboratory study of efficacy and withdrawal.
Clonazepam 0.5 mg was evaluated in a sleep laboratory study of 6 insomniac patients. The 16-night protocol consisted of 4 placebo-baseline nights, 7 nights of drug administration and 5 placebo-withdrawal nights. Clonazepam produced a significant decrease in total wake time initially (nights 5-7), as well as with continued administration (nights 9-11). With later but not immediate withdrawal, significant rebound insomnia occurred, on the 3rd withdrawal night, both wake time after sleep onset and total wake time increased markedly, with the latter significantly increased. These findings are discussed in light of clonazepam's increasing use for panic disorder; specifically, due to its maintained efficacy, it has the advantage of avoiding interdose rebound anxiety which is frequently reported with use of alprazolam.
An update on sleep disorders.
Sleep disorders are so common that approximately 38% of the general population complains about a current sleep problem and 52% complains about a current or past sleep problem. Psychiatric factors are prominent in virtually all sleep disorders, either as primary factors (insomnia and adult parasomnias) or as significant secondary consequences (sleep apnea and narcolepsy). The authors describe normal sleep; delineate the prevalence of sleep disorders, both those associated with psychiatric disturbance and those of organic etiology; and outline procedures for evaluation and treatment, which is multidimensional and comprises general measures, psychotherapy, and, when indicated, pharmacotherapy.
Effects of nadolol on blood pressure, sleep efficiency, and sleep stages.
The effects of nadolol (20 and 80 mg) on blood pressure and sleep parameters were assessed in six patients with mild hypertension. A 32-night experimental protocol in the sleep laboratory was instituted consisting of four placebo-baseline nights followed by 4 weeks of drug administration. Both doses of nadolol had a clear-cut and consistent lowering effect on blood pressure throughout the night and during the day, with a greater reduction noted with the 80 mg dose. In fact, blood pressure values were reduced to normotensive levels. Neither dose had a disrupting effect on sleep, whereas the 80 mg dose improved sleep efficiency and also had a rapid eye movement-enhancing effect. This absence of sleep-disrupting effects is attributed to nadolol's low level of lipophilicity and lack of intrinsic sympathomimetic activity. The clinical significance of the lack of sleep disruption and possible improvement of sleep with nadolol is discussed in light of the well-recognized sleep disturbances produced by other beta-blockers.
Alprazolam: effects on sleep and withdrawal phenomena.
Alprazolam was evaluated in chronic insomniacs in a 1-mg bedtime dose. The 16-night sleep laboratory protocol included four placebo-baseline nights followed by seven nights of drug administration and five placebo-withdrawal nights. On the first three drug nights (nights 5 to 7), the drug was highly effective in inducing and maintaining sleep with this short-term use. By the end of the one week of administration (nights 9 to 11), however, the drug had lost about 40% of its efficacy. During drug use, one subject reported some difficulty in controlling expression of inappropriate emotions when interacting with others, which suggested the presence of disinhibition. On the third night following drug termination, there was a significant increase in sleep difficulty above baseline levels (rebound insomnia). This worsening was of comparable magnitude to the peak improvement of sleep with drug administration. Thus, the clinical utility of alprazolam when administered to insomniac patients appears to be limited because of a relatively rapid development of tolerance and possible disinhibitory reactions during drug use and the occurrence of rebound insomnia following withdrawal.
Disorders of excessive sleepiness: narcolepsy and hypersomnia.
Besides sleep apnea, the main disorders of excessive daytime sleepiness include narcolepsy and hypersomnia. Narcolepsy is characterized by periods of irresistible sleepiness and sleep attacks of brief duration and, most often, by one or more of the auxiliary symptoms: cataplexy, sleep paralysis, and hypnogogic hallucinations. Generally, sleepiness and sleep attacks in hypersomnia are of longer duration and are more resistible than in narcolepsy; also, the auxiliary symptoms are absent. There are three types of hypersomnia: idiopathic, secondary, and periodic. Nocturnal sleep is typically disrupted in narcolepsy, whereas in idiopathic hypersomnia it is prolonged and in secondary hypersomnia it is variable. The exact causes of narcolepsy and idiopathic hypersomnia are unknown; however, there is evidence for genetic predisposition for either disorder. In secondary hypersomnia causative factors include: neurologic, such as head injuries, cerebrovascular insufficiency, and brain tumors; general medical, such as metabolic disorders, various intoxications, and conditions leading to brain hypoxia; and psychiatric, most notably depression. Although the cause of periodic hypersomnia is unclear, most research supports the notion of underlying organic disease. Often, the evaluation of patients with excessive daytime sleepiness can be completed in the office setting, based on the sleep history and a thorough neurologic, general medical, and psychiatric assessment. Whenever indicated, ancillary laboratory studies, such as computed tomography and magnetic resonance scans, should be performed. Sleep laboratory recordings generally are not necessary unless there is suspicion of sleep apnea or narcolepsy in the absence of auxiliary symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)
Clinical neuropharmacology of sleep disorders.
Within the context of the comprehensive treatment of sleep disorders, which includes medical, neurologic, psychiatric, and social interventions, use of medication is often indicated. Among the three benzodiazepine hypnotics that are available in the United States for the treatment of insomnia, flurazepam is effective for both sleep induction and maintenance, and it retains most of its efficacy over a 4-week period of nightly administration; temazepam is effective only for sleep maintenance, and triazolam improves both sleep induction and maintenance with initial but not with continued administration. Rebound phenomena are more frequent and intense with the more rapidly eliminated drug, triazolam, and to a lesser degree with temazepam. Also, with triazolam, certain behavioral side effects, such as amnesia and psychotic-like symptoms, have been reported. With flurazepam, which is a slowly eliminated benzodiazepine, daytime sedation is more frequent than with the other two drugs. When insomnia is secondary to major depression, antidepressant medication should be administered. Methylphenidate, amphetamines, or other stimulant medications are used for the symptomatic treatment of the sleepiness and sleep attacks of narcolepsy and hypersomnia. For cataplexy and the other two auxiliary symptoms of narcolepsy, imipramine or other tricyclics are the drugs of choice. Protriptyline and medroxyprogesterone have been used in treating mild cases of obstructive sleep apnea, but their efficacy is limited. Similarly, for the treatment of central sleep apnea, medroxyprogesterone and acetazolamide have shown only limited effects. Medication for patients with sleepwalking, night terrors, or nightmares should be prescribed judiciously, and primarily when treatment of an underlying psychiatric condition is desired. The neuropharmacology of sleep should also consider drugs that may cause sleep disorders. Medications with sleep disturbing effects include various antihypertensives, bronchodilators, and the energizing antidepressants. Withdrawal of REM-suppressant drugs, such as the barbiturates, may cause nightmares in association with a REM rebound. Occasionally, a drug or a combination of drugs may produce somnambulistic-like activity in some patients.
Uvulopalatopharyngoplasty as a treatment of obstructive sleep apnea precipitated by uvular prolapse.
Two patients are discussed in whom obstructive sleep apnea was precipitated by uvular prolapse into the larynx and successfully treated by uvulopalatopharyngoplasty. Although tracheostomy has been the definitive treatment for obstructive sleep apnea, uvulopalatopharyngoplasty has also been used as an alternative surgical procedure. However, indications for its successful use have not been clearly defined. Our experience illustrates that the surgical approach to obstructive sleep apnea is dependent on a thorough diagnostic evaluation that includes a sleep history, head and neck examination, hypnopolygraphic recording and, if indicated, nocturnal fiberoptic endoscopy.
Comparison of short and long half-life benzodiazepine hypnotics: triazolam and quazepam.
Two benzodiazepine hypnotics, triazolam, 0.25 mg, with a short elimination t1/2, and quazepam, 15 mg, with a long t1/2, were evaluated in 22-night sleep laboratory studies. Quazepam improved sleep significantly during both short- and intermediate-term use. Daytime sleepiness, which decreased with continued use, was the side effect most often associated with quazepam dosing. In contrast, triazolam dosing did not significantly improve any of the major sleep efficiency parameters, and there was a rapid development of tolerance for the drug's slight initial effectiveness. In addition, there were a number of behavioral side effects including amnesia, confusion, and disinhibition. Withdrawal of triazolam was associated with sleep and mood disturbances (rebound insomnia and rebound anxiety), whereas quazepam exerted carryover effectiveness. Thus the data in this study show that the 0.25 mg dose of triazolam, which is being prescribed increasingly, has a profile of side effects that is similar to that of the 0.5 mg dose.
Narcolepsy/cataplexy. III: Nocturnal sleep and wakefulness patterns.
Nocturnal sleep and wakefulness patterns of 50 patients with narcolepsy and cataplexy were compared to those of 50 control subjects. A sleep onset REM period (SOREM) occurred in 22 (44%) of the patients but in none of the controls. Comparisons among patients showing a SOREM, patients without this abnormality, and controls demonstrated that the timing, number and duration of the remaining REM periods did not differ across the three groups. Thus, the basic REM sleep disturbance in narcolepsy appears to relate to the timing of onset of the initial REM period. This finding lends further support to the theory of dual control of REM-NREM cycling. While narcoleptics took significantly less time to fall asleep, they had significantly more awakenings, wake time after sleep onset and total wake time. The disturbed sleep experienced by patients could not be accounted for by the presence of a sleep onset REM period or the use of medication. Nocturnal wakefulness appeared to be distributed in a regular oscillating manner throughout the recording period similar to the pattern of daytime vigilance previously reported in normal subjects. Thus, typical nocturnal dampening of daytime ultradian vigilance rhythms may be lost in the narcoleptic patient.