Melatonin, hypnotics and their association with fracture: a matched cohort study.

OBJECTIVES: although melatonin prescribing in England has been increasing in recent years, there have been no large scale studies on the safety of melatonin compared to other medical treatments for insomnia. The primary aim of this study was to examine the association between exposure to melatonin, hypnotic benzodiazepines (temazepam, nitrazepam) or Z-drugs (zolpidem, zopiclone) and fracture risk. DESIGN: retrospective cohort study. SETTING: 309 general practices contributing to The Health Improvement Network (THIN) between 2008 and 2013. PARTICIPANTS: 1,377 patients aged 45 years and older prescribed melatonin; 880 patients prescribed hypnotic benzodiazepines; 1,148 patients prescribed Z-drugs and 2,752 unexposed controls matched by age, gender and practice. MAIN OUTCOME: fracture following prescription of study drugs ascertained from practice records. RESULTS: the unadjusted hazard ratios for fracture during the follow-up period were 1.90 (95% CI 1.41-2.57) for melatonin, 1.70 (95% CI 1.18-2.46) for hypnotic benzodiazepines and 2.03 (95% CI 1.45-2.84) for Z-drugs. After adjustment for 26 covariates, the hazard ratios were 1.44 (95% CI 1.01-2.04) for melatonin, 1.26 (95% CI 0.82-1.92) for hypnotic benzodiazepines and 1.52 (95% CI 1.04-2.23) for Z-drugs. Only patients with three or more melatonin prescriptions had elevated risk. The mean time to fracture was 1.04 years and there was no significant difference in mean time to fracture between the cohorts. CONCLUSIONS: in this large cohort of patients attending UK primary care, prescriptions for melatonin and Z-drugs were associated with a significantly increased risk of fracture. With the use of melatonin increasing steadily overtime, this study adds to the literature on the safety profile of this drug.

Rebound insomnia: a new clinical syndrome.

Rebound insomnia followed the withdrawal of three benzodiazepine hypnotic drugs, each of which had been administered in a single nightly dose for only short-term periods. The intense worsening of sleep is attributed to the short duration of the action of these drugs. A hypothesis involving benzodiazepine receptors in the brain is proposed in which there is a delay or lag in replacement of endogenous benzodiazepine-like molecules after the abrupt withdrawal of exogenous drugs.

Road traffic accident risk related to prescriptions of the hypnotics zopiclone, zolpidem, flunitrazepam and nitrazepam.

BACKGROUND: Despite the high prescription rate of benzodiazepine-like hypnotics (z-hypnotics), there is limited information on the road traffic accident risk associated with the use of these drugs. We wanted to investigate whether filling a prescription for zopiclone or zolpidem was associated with increased risk of road traffic accidents at a national population level. Nitrazepam and flunitrazepam were used as comparator drugs. METHOD: All Norwegians 18-69 years (3.1 million) were followed-up from January 2004 until the end of September 2006. Information on prescriptions, road traffic accidents and emigration/death was obtained from three Norwegian population-based registries. The first week after the hypnotics had been dispensed was considered to be the exposure period. Standardized incidence ratios (SIRs) were calculated by comparing the incidence of accidents in the exposed person-time to the incidence of accidents in the unexposed person-time. RESULTS: During exposure, 129 accidents were registered for zopiclone, 21 for zolpidem, 27 for nitrazepam and 18 for flunitrazepam. The SIRs were (SIR for all ages and both sexes combined; 95% CI): z-hypnotics (zopiclone+zolpidem) 2.3; 2.0-2.7, nitrazepam 2.7; 1.8-3.9 and flunitrazepam 4.0; 2.4-6.4. The highest SIRs were found among the youngest users for all hypnotics. CONCLUSIONS: This study found that users of hypnotics had a clearly increased risk of road traffic accidents. The SIR for flunitrazepam was particularly high.

Identification of enzymes responsible for nitrazepam metabolism and toxicity in human.

Nitrazepam (NZP) is a hypnotic agent that rarely causes liver injuries in humans and teratogenicity in rodents. In humans, NZP is primarily metabolized to 7-aminonitrazepam (ANZP) by reduction and subsequently to 7-acetylamino nitrazepam (AANZP) by acetylation. ANZP can be regenerated from AANZP by hydrolysis in rodents, but it is still unclear whether this reaction occurs in humans. In rodents, AANZP may be associated with teratogenicity, while in humans, it is known that drug-induced liver injuries may be caused by NZP reactive metabolite(s). In this study, we attempted to identify the enzymes responsible for NZP metabolism to obtain a basic understanding of this process and the associated metabolite toxicities. We found that the NZP reductase activity in human liver cytosol (HLC) was higher than that in human liver microsomes (HLM). We purified the responsible enzyme(s) from HLC and found that the NZP reductase was aldehyde oxidase 1 (AOX1). The role of AOX1 was confirmed by an observed increase in the NZP reductase activity upon addition of N1-methylnicotinamide, an electron donor of AOX1, as well as inhibition of this activity in HLC in the presence of AOX1 inhibitors. ANZP was acetylated to form AANZP by N-acetyltransferase (NAT) 2. An experiment using recombinant esterases in an inhibition study using HLM revealed that AANZP is hydrolyzed by arylacetamide deacetylase (AADAC) in the human liver. N-Hydroxylamino NZP, which is suspected to be a reactive metabolite, was detected as a conjugate with N-acetyl-l-cysteine through NZP reduction and ANZP hydroxylation reactions. In the latter reaction, the conjugate was readily formed by recombinant CYP3A4 among the various P450 isoforms tested. In sum, we found that AOX1, NAT2, AADAC, and CYP3A4 are the determinants for the pharmacokinetics of NZP and that they confer interindividual variability in sensitivity to NZP side effects.

Modeling cumulative dose and exposure duration provided insights regarding the associations between benzodiazepines and injuries.

BACKGROUND AND OBJECTIVES: Accurate assessment of medication impact requires modeling cumulative effects of exposure duration and dose; however, postmarketing studies usually represent medication exposure by baseline or current use only. We propose new methods for modeling various aspects of medication use history and employment of them to assess the adverse effects of selected benzodiazepines. STUDY DESIGN AND SETTING: Time-dependent measures of cumulative dose or duration of use, with weighting of past exposures by recency, were proposed. These measures were then included in alternative versions of the multivariable Cox model to analyze the risk of fall related injuries among the elderly new users of three benzodiazepines (nitrazepam, temazepam, and flurazepam) in Quebec. Akaike's information criterion (AIC) was used to select the most predictive model for a given benzodiazepine. RESULTS: The best-fitting model included a combination of cumulative duration and current dose for temazepam, and cumulative dose for flurazepam and nitrazepam, with different weighting functions. The window of clinically relevant exposure was shorter for flurazepam than for the two other products. CONCLUSION: Careful modeling of the medication exposure history may enhance our understanding of the mechanisms underlying their adverse effects.

Is long-term use of benzodiazepine a risk for cancer?

The carcinogenicity of benzodiazepines (BZDs) is still unclear. We aimed to assess whether long-term benzodiazepines use is risk for cancer.We conducted a longitudinal population-based case-control study by using 12 years from Taiwan National Health Insurance database and investigated the association between BZDs use and cancer risk of people aged over 20 years. During the study period, 42,500 cases diagnosed with cancer were identified and analyzed for BZDs use. For each case, six eligible controls matched for age, sex, and the index date (ie, free of any cancer in the date of case diagnosis) by using propensity score. For appropriate risk estimation, we observed the outcomes according to their length of exposure (LOE) and defined daily dose (DDD). To mimic bias, we adjusted with potential confounding factors such as medications and comorbid diseases which could influence for cancer risk during the study period. The data was analyzed by using Cox proportional hazard regression and conditional logistic regression.The finding unveils benzodiazepines use into safe and unsafe groups for their carcinogenicity. The use of diazepam (HR, 0.96; 95%CI, 0.92-1.00), chlorodizepoxide (HR, 0.98; 95%CI, 0.92-1.04), medazepam (HR, 1.01; 95%CI, 0.84-1.21), nitrazepam (HR, 1.06; 95%CI, 0.98-1.14), oxazepam (HR, 1.05; 95%CI, 0.94-1.17) found safer among BZDs. However, clonazepam (HR, 1.15; 95%CI, 1.09-1.22) were associated with a higher risk for cancers. Moreover, specific cancer risk among BZDs use was observed significantly increased 98% for brain, 25% for colorectal, and 10% for lung, as compared with non-BZDs use.Diazepam, chlordiazepoxide, medazepam, nitrazepam, and oxazepam are safe among BZDs use for cancer risk. Our findings could help physicians to select safer BZDs and provide an evidence on the carcinogenic effect of benzodiazepines use by considering the LOE and DDD for further research.

Absence seizures: valproate or ethosuximide?

A series of 47 children with absence seizures was analysed retrospectively. Fourteen of these children also had other types of seizures, and four had repeated episodes of absence status. The age at onset of absence seizures ranged from 1 1/2 to 13 years (mean, 7.9 years). The mean follow-up was 5.5 years. Ethosuximide (ESM) was used as the drug of first choice in 43 children, and valproate (VPA) was used first in 4 children; 15 of the patients later received VPA alone or in combination with ESM. A 100% reduction in seizure frequency was achieved in 38 children (80.8%). Of these, 23 has received ESM (21 ESM; 2 ESM + nitrazepam) and 15 had received VPA (6 VPA; 9 VPA + ESM). Of the latter group, 11 children had had an unsuccessful trial of ESM. VPA was superior in the treatment of children who had EEG polyspikes or absence status. A seizure reduction of 50% to 75% was achieved in 7 children (14.9%). Two patients (4.3%) had refractory seizures. A transient Stevens-Johnson syndrome occurred in a patient treated with ESM. Other side effects were mild and transient. Both ESM and VPA are needed in the treatment of absence seizures. In refractory cases, the combination of these drugs appears to be beneficial.

Infantile spasms. Comparative trial of nitrazepam and corticotropin.

Fifty-two patients were enrolled in a four-week randomized multicenter study comparing nitrazepam and corticotropin in the treatment of infantile spasms. The drugs' efficacy was evaluated in 48 patients, all less than 2 years of age. Both treatments resulted in a statistically significant reduction in spasm frequency from that at baseline, but the difference between treatments was not significant. The number of patients who experienced side effects was similar in the two treatment groups, but the adverse effects encountered among the patients treated with corticotropin were qualitatively more severe and required the discontinuation of treatment in six patients.

Zopiclone versus nitrazepam: a double-blind comparative study of efficacy and tolerance in elderly patients with chronic insomnia.

A randomized, double-blind, comparative trial of zopiclone versus nitrazepam was conducted in 74 geriatric chronic insomniac patients. Following a 7-day wash-out period, two parallel groups, successively received a placebo for 7 days, then either 7.5 mg zopiclone or 5 mg nitrazepam for another 7-day period. Efficacy on sleep was assessed by a sleep analogue scale and the Spiegel Sleep Questionnaire, residual effects by psychometric tests and tolerance by a standardized question, as well as by clinical and laboratory tests. Zopiclone and nitrazepam were more active than placebo on all tests of efficacy. In contrast with nitrazepam, zopiclone was devoid of effect on neurological function. In addition, the condition on awakening was better with zopiclone.

Zopiclone and nitrazepam: a multicenter placebo controlled comparative study of efficacy and tolerance in insomniac patients in general practice.

The efficacy and tolerance of zopiclone were compared with nitrazepam and placebo in a multicenter double-blind parallel-group study in insomniac patients. Following a 7-day placebo washout period, 99 patients (age range 20 to 69 years) received oral capsules of 7.5 mg zopiclone or 5 mg nitrazepam or placebo for 2 weeks. During the fourth week all patients received placebo treatment. Sleep assessments by the patients showed that, compared with placebo, zopiclone and nitrazepam improved all sleep measures of efficacy from the first night and that effectiveness was maintained throughout treatment. The physicians global assessment of efficacy also favored zopiclone and nitrazepam over placebo treatment. Subjective morning drowsiness during treatment was significantly less for zopiclone than for either nitrazepam or placebo and represents a clear advantage for ambulatory patients. No rebound insomnia was evident during a 7 day post-treatment withdrawal period for either zopiclone or nitrazepam. Tolerance was good for all treatments.

Chronic administration of zopiclone and nitrazepam in the treatment of insomnia.

The hypnotic effects of 7.5 mg zopiclone, as well as its unwanted and residual effects, were compared with those of 5 mg nitrazepam in a double-blind, randomized, multicenter, parallel group study. After an initial, 7-day, placebo wash-out period, insomniac out-patients under the care of general practitioners received either 7.5 mg zopiclone or 5 mg nitrazepam for 6 weeks. Everyday, the patients filled in a diary (analogue scales for sleep parameters and condition during daytime); a sleep questionnaire was filled in at baseline and at the end of active treatment period; every 2 weeks, a somatic complaint check-list inventory and a mood rating scale were filled in and psychomotor tests performed; and at the end of the study, a global evaluation of efficacy and acceptability was given by the investigator. Clinical laboratory tests were performed before and after the active treatment period. From the diary, sleep onset latency, as well as sleep quality, were similarly improved by both drugs throughout the whole study. From the sleep questionnaire, all sleep parameters measured were improved at the end of the 6-week treatment period in both groups. No statistical differences in the various psychomotor tests were observed between the two treatment groups, and a significant improvement in the working ability of patients was noted with both drugs. Some significant differences were observed in the mood rating scale and the somatic complaint check list, probably related to differences in pharmacokinetics of the two drugs.

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.

Residual effects of hypnotics: triazolam, flurazepam, and nitrazepam.

The residual effects of three hypnotics were investigated by the method of 24-h polygraphy (EEG, EMG, and EOG). The drugs were triazolam 0.25 mg and 0.5 mg, flurazepam 15 mg and 30 mg, nitrazepam 5 mg and 10 mg, and placebo. The subjects were healthy volunteers, eight men and eight women with an average age of 34.3 years. The number of total polygraphic records was 77. Triazolam 0.25 mg and 0.5 mg, flurazepam 30 mg, and nitrazepam 10 mg showed definited sleep inducing and sleep maintenance effects in night recordings. Flurazepam 15 mg and 30 mg and nitrazepam 5 mg and 10 mg were followed by residual effects in morning, afternoon and evening recording periods on the day after the administrations of the hypnotics. However, no effects were seen on the day after the administration of triazolam 0.25 mg and 0.5 mg except for some slight residual effects in the morning. Thus triazolam 0.25 mg and 0.5 mg produces less residual effect than do flurazepam 15 mg and 30 mg, and nitrazepam 5 mg and 10 mg, and 24-h polygraphy is useful for measuring the residual effects of hypnotics.

A comparison between chlormethiazole and nitrazepam as hypnotics in psycho-geriatric patients.

A double-blind crossover study was carried out in 68 demented elderly patients (mean age 77 years) to compare the hypnotic effects of chlormethiazole and nitrazepam. Chlormethiazole was administered as a 5% mixture (500 mg. chlormethiazole edisylate) in a 10 ml. dose: the corresponding single dose of nitrazepam was 10 mg. Treatment was discontinued in 6 patients and interrupted for from 1 to 3 days in a further 18 due to side-effects and 'hang-over' problems or because of intercurrent infections. Of these 24 drop-outs, 3 occurred during chlormethiazole treatment (1 severe 'hang-over'; 2 refused to take medication) and 21 during nitrazepam (15 severe 'hang-over' effects, including sleepiness and muscular weakness; 2 nausea; 4 intercurrent infection). Both preparations were equally effective as hypnotics, there being no noteworthy differences in time of onset or in duration of sleep. Of the 44 patients completing the trial without interuption, observations were carried out for 308 nights on each preparation. Chlormethiazole patients slept for more than 6 hours on 244 of the 308 nights without 'hang-over' effect the next day compared with 163 out of 308 nights of those on nitrazepam. The difference is statistically significant in favour of chlormethiazole. The high incidence of 'hang-over' effect during nitrazepam treatment indicates that a single 10 mg. dose is too large for use in the elderly. Overall assessment of treatment was made in 62 patients. Chlormethiazole was judged to be the most suitable drug in 37, nitrazepam in 11, and both preparations equally useful in the remaining 14 patients. This difference is statistically significant.

The psychomotor effects of single and repeated doses of hypnotic benzodiazepines.

Benzodiazepine hypnotics are used for short periods in low doses in healthy people when stressed and in patients with insomnia. This study examined psychomotor impairment in healthy young males and females after 1 and 7 nights of flunitrazepam (1 mg), nitrazepam (2.5 mg) and temazepam (10 mg). There were substantial inter-individual variations. Results showed that no drug significantly affected psychomotor performance at these doses after single or repeated administration. The number and severity of side-effects were significantly greater after the first night with temazepam and 7 nights with nitrazepam, although this may reflect a statistical artefact rather than a significant clinical finding. The difficulties in performing adequately controlled psychopharmacological studies at low doses are highlighted. Given the large intra- and inter-subject variances, small drug effects would necessitate large sample sizes (21 to 600 subjects at the 95% level of chance of detection) depending on the variable. The study suggests there is minimal impairment with low dose hypnotic drugs and a need to individualize treatment.

Lack of evidence of teratogenicity of benzodiazepine drugs in Hungary.

In order to investigate possible teratogenic effects of commonly used benzodiazepines (diazepam, chlordiazepoxide, nitrazepam) in Hungary, four approaches were used: 1. A retrospective case-control study of 630 cases with isolated cleft lip +/- cleft palate, 179 cases with isolated cleft palate, 392 cases of multiple congenital anomalies including cleft lip and/or cleft palate, and their matched control cases; 2. The Case-Control Surveillance System of Congenital Anomalies in Hungary, 1980 to 1984, involving 355 cases with isolated cleft palate, 417 cases with multiple congenital anomalies, and 186 cases with Down's syndrome (as positive controls). Benzodiazepines were taken by 14.9% of 11,073 control pregnant women studied; 3. A prospective study of 33 pregnant women attending the Counselling Clinic following ingestion of benzodiazepines during the first trimester of pregnancy; 4. An observational study involving 12 pregnant women who attempted suicide and one with accidental overdosage with benzodiazepines during pregnancy. None of these four approaches gave any indication of an association between facial clefting and in utero exposure to these substances.

Nitrazepam for refractory infantile spasms and the Lennox-Gastaut syndrome.

Infantile spasms and the Lennox-Gastaut syndrome are considered to be age-specific pediatric epileptic syndromes and together constitute a significant percentage of medically resistant seizures in childhood. Twenty children, ages 4 to 28 months (median, 12 months), with medically refractory infantile spasms or the Lennox-Gastaut syndrome, were treated with the investigational benzodiazepine nitrazepam in an open-label study. Daily dosage of nitrazepam ranged from 0.5 to 3.5 mg/kg, with a median dosage of 1.5 mg/kg, divided into two doses per day. Side effects included pooling of oral secretions (12 children) and sedation (six children); however, no serious side effects were seen. Responses to nitrazepam were as follows: five complete responses (cessation of all seizures), seven partial responses (greater than 50% reduction of seizures), and eight with no response. Median duration of response was 9 months (range, 4 to 16 months) in children with infantile spasms and 14 months (range, 8 to 26 months) in children with the Lennox-Gastaut syndrome. Nitrazepam is an effective anticonvulsant in this small cohort of children with medically refractory infantile spasms and the Lennox-Gastaut syndrome, resulting in a 25% response rate and only modest side effects.

Intermittent treatment of febrile convulsions with nitrazepam.

Intermittent oral or rectal administration of diazepam for the prophylactic treatment of febrile convulsions has given results comparable to the continuous use of phenobarbital while limiting side effects and risks of toxicity. Since we believe that nitrazepam is a better anticonvulsant than diazepam, we performed a study to evaluate the effectiveness of this medication in the prophylactic treatment of febrile convulsions. Nitrazepam was given only when the children had fever and almost exclusively in children with a high risk of recurrence (less than 12 months of age at first convulsion; atypical convulsion; one or several previous convulsions). Thirty one children with a high risk of recurrence received nitrazepam. The rate of recurrence in this group was 19.3% after a follow-up of 16 months, compared to 45.8% in 24 children who also had a high risk of recurrence but in whom the parents refused the medication or gave it inadequately (p less than 0.05). Fifty one children with a low risk of recurrence also were evaluated and followed for at least 12 months (mean 15.4 months). Six were treated with nitrazepam, mostly because of parental anxiety, and none had a recurrence; of the 45 untreated children in this group, 6 (13.6%) had another convulsion. These results show the efficiency of nitrazepam in the prophylactic treatment of febrile convulsions.

Nitrazepam for periodic movements in sleep (sleep-related myoclonus).

In a follow-up study (mean, approximately six months), nitrazepam was helpful in suppressing periodic movements in sleep (sleep-related myoclonus) and improving disturbed sleep physiology and daytime symptoms of 13 patients (mean age - 53 yr).

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.