Rocco 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.

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 a 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.

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. Lovastatins sleep disturbing effects with continued administration are attributed to its high degree of lipophilicity in contrast with the hydrophilicity of pravastatin.

Inhibition of theophylline metabolism by long‐term allopurinol administration

Administration of an oral dose of allopurinol (300 mg every 12 hr) for 14 consecutive days increased the mean theophylline area under the curve (AUC) 27% and mean theophylline half‐life (t½) 25%, whereas the mean theophylline clearance (Cl) decreased 21%. Allopurinol did not alter either apparent volume of distribution (aVd) or gastrointestinal absorption (Cmax and tmax) of theophylline. After 28 consecutive days of allopurinol administration, theophylline disposition was the same as that on day 14. Thus, given in a dose of 300 mg every 12 hr for 14 or 28 days, allopurinol inhibits theophylline metabolism, despite the failure of allopurinol in lower doses given for only 7 days to alter theophylline disposition. These results emphasize the need to investigate several different doses and durations of administration within therapeutic ranges before firm conclusions can be drawn concerning the influence of one drug on the disposition of another.

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 drugs 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.

USEFULNESS OF POLYSOMNOGRAPHIC STUDIES IN THE DIFFERENTIAL DIAGNOSIS OF INSOMNIA

The prevalence of sleep apnea, sleep apneic activity, nocturnal myoclonus, and nocturnal myoclonic activity was assessed in 375 outpatient insomniacs and 150 normal controls. Only a small percentage of insomniacs (n = 8, 2.3%) and normal controls (n = 2, 1.3%) presented > or = 30 apneic events per night. Only one of these subjects, an insomniac, met the laboratory and clinical criteria of sleep apnea sufficient to recommend treatment. A limited amount of sleep apneic activity per subject (only 3-29 apneic events per night) was evenly distributed between insomniacs (n = 52, 13.9%) and normal controls (n = 22, 14.7%). Also, small percentages of insomniacs (n = 43, 11.5%) and normal controls (n = 11, 8.5%) displayed nocturnal myoclonus (five or more leg movements per hour) or nocturnal myoclonic activity (less than five movements per hour). Thus, these results do not support the claim that sleep apnea or nocturnal myoclonus are common causes of insomnia. In addition, different cutoff points of REM latency (based on first-night recordings) were associated with very low sensitivity and moderately high specificity resulting in inadequate levels of diagnostic accuracy in differentiating depressed insomniacs from non-depressed insomniacs. Finally, empirically optimized values for REM variables were less successful than similarly optimized MMPI values in differentiating depressed insomniacs from nondepressed ones. In conclusion, with our current level of knowledge, polysomnography has limited clinical usefulness in the differential diagnosis of insomnia.

Validity and clinical utility of sleep laboratory criteria for insomnia.

The sensitivity, specificity, and positive predictive value of two proposed sleep laboratory criteria for the diagnosis of insomnia were evaluated in 375 adults with a primary complaint of insomnia and 150 noninsomniac controls. The two criteria used results in either low sensitivity and moderately strong specificity or high sensitivity and low specificity and, accordingly, in both cases weak positive predictive values (diagnostic accuracy), both for one night and multiple nights of recordings. Further, an empirically optimized criterion also resulted in an unsatisfactory diagnostic accuracy. Finally, the optimized MMPI criteria were superior to optimized sleep criteria in differentiating insomniacs from controls. In conclusion, sleep laboratory recordings provide little relevant information for confirming or excluding the presence of insomnia.

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.

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 clonazepams 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.

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.