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At least 19 recordsLinked to original sources

Nitrazepam-induced cricopharyngeal dysphagia, abnormal esophageal peristalsis and associated bronchospasm: probable cause of nitrazepam-related sudden death.

Nitrazepam was used in the treatment of resistant myoclonic epilepsy in 38 children. After the occurrence of nitrazepam-associated swallowing incoordination, high-peaked esophageal peristalsis and related bronchospasm in one patient, we initiated a prospective study of esophageal manometry using a station pull-through technique with a pediatric 4-channel continuous perfusing system. Three more patients were found to have delayed cricopharyngeal relaxation and high-peaked esophageal peristaltic waves. The initial patient developed severe respiratory distress and bronchospasm necessitating ventilatory support while on nitrazepam and improved dramatically with subsequent normal manometric study following nitrazepam discontinuation. Nitrazepam was reintroduced for its anticonvulsant and cognitive benefits and was tolerated at a reduced dosage. We postulate a central nervous system effect of nitrazepam promoting parasympathetic overactivity or vagotonia which can cause potentially fatal respiratory distress. Care must be exercised in nitrazepam use and esophageal manometry may be helpful in defining patients at greater risk for sudden death.

Adolescent

Plasma nitrazepam concentrations after an acute intake and their correlation to sedation and serum growth hormone levels.

Concentrations of nitrazepam in plasma were determined by gas chromatography in healthy volunteers after an acute peroral administration of nitrazepam (5 and 10 mg). Placebo tablets were also used, and an assessement of subjective drug effects was made during each medication. In addition serum growth hormone levels were determined. The peak plasma nitrazepam concentration was achieved at 120 minutes (46.9 +/- 3.2 ng/ml, mean +/- S.E.M.) after 5 mg of nitrazepam and at 180 minutes (82.8 +/- 10.5 ng/ml) after the dose of 10 mg. The half-life of nitrazepam in plasma ranged from 16.5 to 48.3 (mean 28.8) hours. A significant positive correlation was seen between the subjective sedative effects and the magnitude of the peak nitrazepam concentrations in plasma. This drug effect was highly significant when the plasma levels of nitrazepam were rising. The subjective sedative effects were more prominent after 10 mg than after 5 mg dose of nitrazepam. The plasma nitrazepam concentration was not significantly correlated with the subjective sedative effect the next morning, 12 hours after the drug intake. Serum growth hormone levels rose significantly during the study both after 5 mg and 10 mg nitrazepam doses (peak levels 16.3 +/- 4.0 and 12.7 +/- 3.1 ng/ml) and were significantly higher than after placebo administration (3.7 +/- 0.7 ng/ml).

Administration, Oral

Determination of nitrazepam and its main metabolites in urine by gas--liquid chromatography: use of electron capture and nitrogen-selective detectors.

Nitrazepam and its main urinary metabolites, 7-aminonitrazepam and 7-acetamidonitrazepam, free and conjugared, were determined from 24-h fractions of human urine after a single oral dose of 5 mg of nitrazepam. Nitrazepam and the metabolites were extracted before and after glusulase hydrolysis with benzene--dichloromethane (90:10) from a 1.0 ml sample. Methylnitrazepam and methylbromazepam served as internal standards. Recoveries were better than 90%. GLC analysis of nitrazepam was performed using a 63Ni electron-capture detector. The metabolites were measured by a dual flameless nitrogen selective detector. The detection limits were about 0.2 ng/ml for nitrazepam and 50 ng/ml for the metabolites. The nitrogen-selective detector responds similarly to all three compounds. The 63Ni electron-capture detector gives very poor response to 7-amino-nitrazepam but allows very sensitive detection of nitrazepam. Combined use of the two detectors gives valuable information about the metabolic profile of nitrazepam.

Adolescent

Comparison of the residual effects of two benzodiazepines (nitrazepam and flurazepam hydrochloride) and pentobarbitone sodium on human performance.

1 The residual effects of two benzodiazepines, nitrazepam (10 mg) and flurazepam hydrochloride (30 mg), and pentobarbitone sodium (200 mg) were studied by adaptive tracking and by reaction time. Performance was measured at 10 h, 13 h, 16 h, 19 h and 34 h after ingestion of each drug. Impaired performance on adaptive tracking was observed at 10 h, 13 h, 16 h and 19 h after nitrazepam and pentobarbitone sodium and at 10 h, 13 h and 16 h after flurazepam hydrochloride. Enhanced performance was observed at 34 h after nitrazepam and pentobarbitone sodium. 2 Increased reaction time persisted to 16 h after nitrazepam, flurazepam hydrochloride and pentobarbitone sodium and reaction time was also increased at 34 h after nitrazepam and pentobarbitone sodium. 3 During the morning immediately after ingestion, the subjects as a group were able to differentiate correctly between placebo and drugs, but they were not able to assess accurately the persistence of the residual effects of nitrazepam and pentobarbitone sodium. 4 Flurazepam hydrochloride would appear to be a more promising benzodiazepine than nitrazepam for use as a hypnotic by persons involved in skilled activity. There was a rapid recovery of performance during the afternoon and, unlike pentobarbitone sodium and nitrazepam, subjects retained the ability to recognize impaired skill.

Adult

Long-term nitrazepam treatment in psychiatric out-patients with insomnia.

Psychiatric patients (N = 26) were treated chronically (from 1 week to 12 years) with nitrazepam, because of insomnia. The patients gave their subjective estimations of the effects and side effects of nitrazepam. The concentrations of nitrazepam in the plasma were measured by 63Ni-EC-gas-liquid chromatography. The pharmacokinetics of nitrazepam were compared between the psychiatric patients and healthy volunteers (N = 11). The steady-state concentrations and the half-life of nitrazepam in the psychiatric patients were comparable to those of the healthy volunteers. The subjective hypnotic effect of nitrazepam was mostly good or satisfactory and remained unchanged during long-term treatment. Only a few, mild side effects were reported. Nitrazepam does not seem to cause enzyme induction with lowered plasma levels and may therefore be of special value in the treatment of chronic insomnia.

Adult

Toxicity of nitrazepam in the elderly: a report from the Boston Collaborative Drug Surveillance Program.

1 To assess the potential hazards of nitrazepam therapy of insomnia in the elderly, adverse reactions to nitrazepam were studied in 2111 hospitalized medical patients who received the drug. 2 Manifestations of unwanted central nervous system (CNS) depression (such as drowsiness or 'hangover') were reported in 49 nitrazepam recipients (2.3%), and signs of unwanted CNS stimulation (such as nightmares, insomnia, agitation, etc.) in 15 (0.7%). None of the adverse reactions were considered serious. 3 Physician-rated clinical efficacy of nitrazepam was not related to dose, but the frequency of both types of adverse reactions increased significantly at higher daily doses. CNS depression also was significantly more frequent in the elderly, being reported in 11% of those aged 80 years or older, whereas the frequency of CNS stimulation was not correlated with age. 4 The effect of age on the reported rate of unwanted CNS depression was most striking at high doses. Among patients aged 80 years or over whose daily dose averaged 10 mg or more, 55% experienced unwanted CNS depression attributed to nitrazepam. 5 Low doses of nitrazepam are safe for elderly individuals, but the elderly are readily susceptible to excessive CNS depression at high doses. The findings suggest that there is little reason to exceed 5mg doses of nitrazepam for most patients, particularly those who are elderly.

Aged

Pharmacokinetics of nitrazepam in saliva and serum after a single oral dose.

The pharmacokinetics of nitrazepam in saliva and serum was studied in 12 healthy volunteers after a single administration of a 5 mg nitrazepam tablet. The binding of nitrazepam to plasma proteins was determined 4 hours after the administration by ultracentrifugation. The analysis of nitrazepam concentrations was performed by 63Ni-EC-GLC. The pharmacokinetic parameters were evaluated manually or by AUTOAN-program in serum, and manually in saliva. The concentrations of nitrazepam in serum and saliva correlated significantly (r = 0.472, P less than 0.001, n = 97). The ratio saliva: serum was, however, time dependent. The protein free fraction in serum was significantly higher (P less than 0.01) than the salivary concentration at the same time (4 hours after administration). The peak concentrations in serum and saliva were 40.7 and 1.9 ng/ml (P less than 0.001) and the times to reach the peak maximum 2.4 and 2.5 hours, respectively (difference not significant). The mean half-life of nitrazepam in serum was 30.5 hrs and in saliva 39.9 hrs, the difference being significant at P less than 0.05. The distribution phase parameters, poorly described before, were calculated. The clinical value of nitrazepam analysis in saliva seems to be negligible.

Administration, Oral

Determination of nitrazepam in serum by gas-liquid chromatography. Application in bioavailability studies.

A gas chromatographic method with electron capture detection has been developed for the analysis of nitrazepam in serum. N-Desmethyldiazepam is used as internal standard. Nitrazepam isolated from serum is converted by acid hydrolysis into 2-amino 5 nitrobenzophenone, which is chromatographed. Metabolites of nitrazepam (7-amino and 7-acetamido compounds) are not included in the determination. Recovery experiments showed that the method is quantitative. The limit of detection is 5 ng/ml of nitrazepam in serum. The method has been used for measuring serum concentrations of nitrazepam in bioavailability studies on subjects given a single dose of nitrazepam tablets.

Biological Availability

Transfer of nitrazepam across the human placenta.

Six women from 14 to 17 weeks pregnant, and 12 woman from 36 to 40 weeks pregnant, were given nitrazepam 5 mg orally about 12 h before legal abortion by hysterotomy in the former group and elective caesarean section in the latter group. The concentration of nitrazepam was determined by gas-liquid chromatography. Binding to plasma proteins was evaluated by separation of the protein-free fraction by ultracentrifugation. In the first group (early pregnancy) the level of nitrazepam was found to be lower in the fetal than in the maternal circulation. The concentration in amniotic fluid was still lower. In the latter group (late pregnancy) the concentration both of unbound and total nitrazepam in maternal and fetal plasma were in equilibrium, which indicated an increase in transplancental transfer in late pregnancy. The percentage of unbound nitrazepam in both cases was 12%.

Adolescent

Human pharmacokinetics of nitrazepam: effect of age and diseases.

Plasma concentrations of nitrazepam were measured by gas-liquid chromatography in: young healthy volunteers, in geriatric and psychiatric patients and in epileptic children. The disposition of nitrazepam was described in terms of a two-compartment open model. After a single oral dose of nitrazepam 5 mg the most prominent differences between the experimental groups were in the beta-phase half-life mean 29 h in the young volunteers and 40 h in geriatric patients , and in the apparent volume of distribution during the beta-phase of 2.4 vs 4.8 1/kg. Total plasma clearance and the average steady state concentration in both groups were equal. The plasma level rose at a rate proportional to the beta-phase half-life, and so, they were achieved more rapidly in the young than in the old subjects (3.5 vs 7.5 d). No change in steady-state level or in the half-life of nitrazepam were found during long term treatment, which indicates lack of enzyme induction or inhibition. In 95% of the epileptic children with a good to fair clinical response, the plasma concentration of nitrazepam was 40-180 ng/ml (mean 114 ng/ml). As all of the patients were on combined antiepileptic therapy, no attempt was made to correlate plasma level with therapeutic response.

Adolescent

A controlled long-term study of flunitrazepam, nitrazepam and placebo, with special regard to withdrawal effects.

The hypnotic effect of flunitrazepam (Ro 5-4200), nitrazepam and a placebo was studied in 117 outpatients using hypnotics for at least 3 months prior to the study. They obtained various neurotropic drugs and this and other treatments were unchanged throughout the trial period of 13 weeks. This consisted of 3 weeks on the previously used hypnotic, 3 weeks on a test drug (during the first of these a doubling of the dose was permitted if the initial dose of 1 mg flunitrazepam, 5 mg nitrazepam or one tablet of placebo was not satisfactory) and 4 weeks' observation after a request to stop medication with the test drug. The effects were evaluated every week by self-ratings. Also noted were: the frequency of dose increase after 1 week of the test period, number of drop-outs in the test period, and failure in the attempt to stop taking the test drug. A "psychological concentration test" was done, as was a follow-up interview. The self-ratings had a good reliability and showed that more patients experienced shorter sleep induction, longer sleep time, better sleep quality and a subjective feeling of having had a better rest with flunitrazepam than with either nitrazepam or placebo. There were no differences between the nitrazepam and the placebo groups. Tiredness was the most common side effect and appeared in the same frequency in all groups. The number of patients who increased the dose after 1 week's medication, as well as the number of drop-outs, was significantly higher in the nitrazepam and placebo groups than in the flunitrazepam group. There was no difference in the ability to discontinue the medication between the test groups or between groups having previously used different hypnotics. The "psychological concentration test" did not reveal any differences between groups. It was concluded that withdrawal of a hypnotic in chronic users was not facilitated by the use of a placebo. This was interpreted as due to a strong psychological dependence upon the hypnotics and their lack of pharmacological effects during long-term treatment.

Adult

Acute effects of temazepam and nitrazepam on psychomotor skills and memory.

Twelve pretrained students ingested temazepam, nitrazepam, and placebo, each double blind at one-week intervals in randomized order. Reactive and co-ordinative skills and critical flicker fusion were measured before each drug intake and 1, 2, 3, 6 and 8 hours after it. Short-term memory and paired association learning were measured at 1, 3 and 8 hours. The psychomotor responses to drugs were modified by a sequence effect (not at zero tests) which effect varied depending on the drug and parameter. In multivariance analysis it was included to reveal drug effects. Nitrazepam 10 mg increased reaction and co-ordination errors and also impaired learning and memory. Temazepam 10 mg impaired co-ordinative skills; on a whole it differed from nitrazepam but hardly from placebo. Temazepam 20 mg impaired co-ordination, and learning and memory. Both temazepam 20 mg and nitrazepam were experienced sedative. All drug effects were clearest during the first 3 hours, nitrazepam also impaired learning at 8 hours. Temazepam 20 mg seems suitable as a hypnotic.

Adult

Residual effects of repeated administration of triazolam and nitrazepam in healthy volunteers.

The residual effects of hypnotics were investigated with a long-acting (nitrazepam) and a short-acting (triazolam) benzodiazepine hypnotic in 8 male volunteers. Subjects received placebo, nitrazepam 5 mg, or triazolam 0.25 mg for 7 consecutive nights in a random-order, double-blind crossover design. Daytime sleepiness, psychomotor performance, EEG activity and standing steadiness were assessed in the morning after 1, 4, and 7 days of drug treatment. Plasma concentrations of nitrazepam and triazolam were also assayed. The concentration of nitrazepam increased gradually during the course of treatment and was associated with residual sedative effects on days 4 and 7. Nitrazepam produced no apparent psychomotor impairments in these studies. On the other hand, there was no evidence of drug accumulation after triazolam administration and triazolam showed no residual sedative effects or residual impairment of psychomotor performance during the experiment. Thus, short-acting hypnotics may have an advantage over long-acting hypnotics in terms of producing less residual sedative effects during chronic treatment.

Adult

Efficacy and side effects of nitrazepam and thioridazine as sleeping aids in psychogeriatric in-patients.

The efficacy and side effects of 10 mg of nitrazepam and 25 mg of thioridazine as sleeping aids were measured in 20 psychogeriatric in-patients during the 14th night and morning of drug administration. The trial used a double blind, cross-over design. The effect of nitrazepam was slightly faster than that of thioridazine. After thioridazine, but not after nitrazepam, the patients slept significantly longer than after placebo. Nitrazepam, but not thioridazine, significantly impaired patients' abilities to move and to conduct everyday activities. It is concluded that thioridazine is a suitable sleeping aid for psychogeriatric patients, but that nitrazepam should be avoided.

Aged

Comparative metabolic study of nimetazepam and its desmethyl derivative (nitrazepam) in dogs.

1. Blood levels of nimetazepam after oral administration to dogs were relatively low at early periods after dosage and reached peak levels (7-7-7-9 mug equiv./ml) after 8 h. The time course of blood levels was similar after oral administration of its desmethyl derivative (nitrazepam) to dogs. Blood levels of the latter, however, were low compared with nimetazepam and reached a peak (5-2-6-3 mug equiv./ml) after 4 h. 2. Recoveries of nimetazepam in urine and faeces were 46 and 52% of the dose for 0-24 h, 27 and 34% for 24-48 h and 4 and 6% for 48-72 h, while those of its desmethyl derivative (nitrazepam) were 63 and 71% for 0-24 h, 12 and 21% for 24-48 h and 2 and 3% for 48-72 h. 3. At least four kinds of reaction were involved in the biotransformation of nimetazepam and its desmethyl derivative (nitrazepam): (i) demethylation at N-1 (ii) hydroxylation at C-3, (iii) subsequent glucuronic acid conjugation of 3-hydroxy derivatives and (iv) reduction of the nitro group at C-7 to an amino group. Reaction (i) proceeded very rapidly in dogs, so that the blood metabolites of nimetazepam were closely similar to those of nitrazepam. For both drugs, the major blood metabolite was nitrazepam. Reaction (ii) was rapidly followed by reaction (iii), and glucuronides were predominantly excreted in urine. Reaction (iv) as well as reaction (iii) are important in the excretion of both drugs. The subsequent acetylation of 7-amino group, however, did not occur in dogs as it did in mice and rats.

Animals

Benzodiazepine-induced sedation and cortisol suppression. A placebo-controlled comparison of oxazepam and nitrazepam in healthy male volunteers.

The sedative and cortisol suppressing properties of oxazepam (45 and 60 mg) and nitrazepam (10 and 15 mg) were examined in eight healthy male subjects. The most clear differences between oxazepam and nitrazepam were those seen with respect to the time course and until maximal effect (Tmax) of the different measurements. Nitrazepam showed maximal sedation after 1 h, maximal benzodiazepine level (RRA), and reaction time prolongation after 2 h, and maximal cortisol suppression after 3 h. Oxazepam showed maximal sedation after 2 h, maximal benzodiazepine levels, reaction time prolongation and cortisol suppression after 3 h. After administration of oxazepam (both doses) a transient return to baseline levels of cortisol was demonstrated. Whereas the degree of sedation correlated significantly within drug groups with the concurrent benzodiazepine levels, the Tmax of sedation was recorded 1 h earlier than the peak blood concentration (RRA) for both nitrazepam and oxazepam. The time course for cortisol suppression for the two compounds differed clearly from the other measurements and was not related to the peak blood concentration.

Affect

Nitrazepam premedication for minor surgery.

Sixty-one patients received nitrazepam 5 mg by mouth on the night before operation, followed by 2.5 mg given on the morning of operation and were compared with 60 patients who received no premedication. All were undergoing either therapeutic abortion, by dilatation and curettage, or explorative curettage. The plasma concentrations of nitrazepam were determined by gas chromatography and compared with the clinical effects of the drug. The premedicated patients slept better on the night before operation, and were more sedated and less apprehensive. Headache was more frequent following nitrazepam. There was no significant difference between the groups in respect of dizziness and nausea. The unpremedicated patients had a faster average heart rate. There was no obvious relationship between the plasma concentration of nitrazepam and the quality of sleep, degree of sedation, apprehension, excitement or headache.

Administration, Oral

Cerebrospinal-fluid concentrations of nitrazepam in man.

The concentrations of nitrazepam in the plasma and cerebrospinal-fluid (CSF) of 38 neurological patients were determined by gas chromatography 2-36 hours after a single 5 mg oral dose. The percentage ratio between the mean CSF and the plasma concentrations increased from 8.0% at 2 hours to 15.6% at 36 hours. This percentage rise was significant (P less than 0.001). The maximum concentration of nitrazepam in the plasma was 36.7 +/- 5.7 ng/ml (at 2 hours) and CSF 3.0 +/- 0.3 ng/ml (at 4 hours). During the beta-phase the half-life of nitrazepam in plasma was about 27 hours and in the CSF markedly longer about 68 hours, indicating a very slow elimination of nitrazepam from the CSF.

Administration, Oral