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PubMed1990

Comparison of the effect of two prazepam formulations on psychomotor and cognitive function in healthy volunteers.

A double-blind crossover design was used to evaluate the effect of two different formulations of prazepam, on motor and cognitive functions and subjective symptoms. Ten healthy male volunteers received 20 mg of prazepam both in tablet and liquid (as drops) formulation, separated by a 1 week interval. All subjects completed a battery of 9 performance tests 2.25 h and 4.75 h after drug intake (corresponding to the times of peak plasma concentration). They also rated themselves on eight visual analogue scales before, 2 h, 4.5 h and 8 h following drug intake. A significant difference between liquid drops and tablets was demonstrated in 4 of the 9 performance tests and 2 of the 8 items of the self rating scales. These results suggest that a single dose of prazepam administered in liquid drop form exhibits greater sedative properties than the same dose administered as tablets in healthy volunteers, probably as a result of more rapid absorption.

Chemistry, Pharmaceutical↗
PubMed1987

Comparison of sublingual and oral prazepam in normal subjects. I. Clinical data.

Five normal volunteers received at a 2-week interval a single dose of sublingual or oral prazepam in double-blind and cross-over conditions. All subjects completed a battery of 15 visual analogue scales before drug intake and 7.5, 15, 22.5, 30, 45, 60, 90 min, 2, 3, 5, 6, 7, 8, 9, 10 and 24 h following intake whereas a computerized assessment of vigilance (reaction time) was performed before intake, 15, 30, 60 min, 2, 3, 6, 8, 10 h following intake. Subjects rated themselves significantly more feeble, clumsy, lethargic, and incompetent following sublingual as compared to oral prazepam while a trend in the same direction was noted for the adjectives muzzy and mentally slow. In contrast, reaction time did not exhibit significantly different changes over time between the two forms. These results suggest a subjectively more rapid onset of activity following sublingual compared to oral prazepam.

Administration, Oral↗
PubMed1981

Influence of anxiolytic drugs (Prazepam and Diazepam) on respiratory center output and CO2 chemosensitivity in patients with lung diseases.

Occlusion pressure at 0.1 s (P0.1) and its evolution during progressive hyperoxic hypercapnia (CO2 chemosensitivity) were measured in 40 patients. Most of them (26) were affected by asthma and /or chronic bronchitis and had mild obstruction and hypoxemia. Measurements were made after 2 days of oral prazepam, diazepam or a placebo (single-blind study). Diazepam induced a significant decrease in P0.1 without affecting CO2 chemosensitivity. In contrast, prazepam did not significantly modify P0.1 or CO2 chemosensitivity. However, P0.1 decreased in 5/18 individual cases. 1 week of treatment by prazepam has advantages over diazepam by not depressing respiratory center output.

Asthma↗
PubMed1984

Plasma concentrations and clinical effects after single oral doses of prazepam, clorazepate, and diazepam.

In a double-blind parallel-group pharmacokinetic and pharmacodynamic study, 31 healthy volunteers received single oral doses of prazepam (10 mg), clorazepate (7.5 mg), or diazepam (5 mg). Appearance in plasma of diazepam and of desmethyldiazepam was rapid after administration of diazepam and clorazepate, respectively, with peak plasma concentrations reached within an average of 1 hour. After oral prazepam, however, desmethyldiazepam appeared in blood slowly, with the highest mean concentration at 6 hours postdosage. Clinical self-ratings of fatigue and of "feeling spacey" were significantly different among groups, with changes over baseline being more marked with clorazepate and diazepam than with prazepam. Thus, differences in absorption rate of orally administered benzodiazepines can lead to differences in the intensity of single-dose effects, despite administration of doses that are equivalent in terms of long-term anxiolytic efficacy.

Administration, Oral↗
PubMed2005

Development and validation of a liquid chromatographic/electrospray ionization mass spectrometric method for the quantitation of prazepam and its main metabolites in human plasma.

A method was developed and fully validated for the quantitation of prazepam and its major metabolites, oxazepam and nordiazepam, in human plasma. Sample pretreatment was achieved by solid-phase extraction using Oasis HLB cartridges. The extracts were analysed by high-performance liquid chromatography (HPLC) coupled with single-quadrupole mass spectrometry (MS) with an electrospray ionization interface. The MS system was operated in the selected ion monitoring mode. HPLC was performed isocratically on a reversed-phase XTerra MS C18 analytical column (150 x 3.0 mm i.d., particle size 5 microm). Diazepam was used as the internal standard for quantitation. The assay was linear over a concentration range of 5.0-1000 ng ml(-1) for all compounds analyzed. The limit of quantitation was 5 ng ml(-1) for all compounds. Quality control samples (5, 10, 300 and 1000 ng ml(-1)) in five replicates from three different runs of analysis demonstrated an intra-assay precision (CV) of < or = 9.1%, an inter-assay precision of < or = 6.0% and an overall accuracy (relative error) of < 4.6%. The method can be used to quantify prazepam and its metabolites in human plasma covering a variety of pharmacokinetic or bioequivalence studies.

Calibration↗
PubMed1984

Duration of benzodiazepine clinical activity: lack of direct relationship with plasma half-life. A comparison of single vs divided dosage schedules of prazepam.

The anxiolytic activity and tolerance of two dosage schedules of prazepam, a long plasma half-life benzodiazepine, were compared under double-blind conditions in two groups of 10 inpatients each who met Research Diagnostic Criteria for Generalized Anxiety Disorder and presented chronic and severe symptomatology. Patients received prazepam 40 mg per day on one of two dosage schedules: divided dosage (DD) - 10 mg in the morning and at noon and 20 mg in the evening; or single dosage (SD) - 40 mg in the evening. The 3 weeks of therapy were preceded and followed by 1 week of wash-out for baseline and follow-up assessments, which were performed weekly with the Hamilton Anxiety Scale, Clinical Global Impression, rating of morning drowsiness and evening worsening of symptoms, and patient self-rating of anxiety by means of a visual analogue scale performed both in the morning and in the afternoon. The results showed a clear superiority of the DD over the SD schedule: better anxiolytic efficacy on the Hamilton Anxiety Scale (P less than 0.0005) and on both morning and afternoon visual analogue scales (P less than 0.01 and P less than 0.0002); less morning drowsiness (P less than 0.0001); and steadier anxiolytic effect during the daytime, as globally rated by the investigator (P less than 0.0001) or measured by morning-afternoon differences on the visual analogue scale (P less than 0.005). These results suggest that plasma pharmacokinetics alone may not be sufficient to predict the duration of benzodiazepine anxiolytic activity.

Adult↗
PubMed1988

Comparative single-dose kinetics and dynamics of lorazepam, alprazolam, prazepam, and placebo.

Thirty-nine healthy volunteers received single oral doses of either alprazolam (1 mg), lorazepam (2 mg), prazepam (20 mg), or placebo in a randomized, double-blind, parallel group study. Plasma drug concentrations, subjective self-ratings, and the digit symbol substitution test (DSST) were evaluated during 24 hours after dosage. Alprazolam was absorbed rapidly and produced correspondingly rapid sedation and impaired DSST performance. These effects also resolved rapidly, being similar to placebo by 4 to 6 hours after dosage. Sedative and DSST-impairing effects of lorazepam were of slower onset but longer duration than those of alprazolam. After oral prazepam, appearance of desmethyldiazepam in plasma was slow, with minimal sedative and DSST-impairing effects. Twenty-four hours after dosage, both alprazolam and lorazepam significantly impaired recall of a list of 16 words learned previously 3 hours after dosage. Thus benzodiazepines with approximately equivalent clinical anxiolytic properties may have different sedative, performance-impairing, and amnesic profiles after single doses in healthy volunteers; these differences are explained at least in part by pharmacokinetic variations.

Adult↗
PubMed1986

Solubility of diazepam and prazepam in aqueous non-ionic surfactants.

The solubility of diazepam and prazepam in aqueous polyoxyethylen-10-dodecanol, polyoxyethylen-23-dodecanol and polyoxyethylen-20-hexadecanol, has been determined at 25.0 degrees C. Diazepam seems to achieve a higher micellar penetration than prazepam, in spite of an expected smaller hydrophobic character. Thermodynamic interpretation of the micellar solutions is carried out using the regular solutions approach. A surfactant-independent relation between solubilities of both drugs has been derived.

Diazepam↗
PubMed1984

[Treatment of anxiety with prazepam, 40 mg. A controlled study versus lorazepam].

Anxiolytic effects and tolerance of a four weeks treatment with prazepam (single dose of 40 mg in the evening) and with lorazepam (3 daily doses of 1.25 mg) are compared in a double blind study. Patients were treated by psychiatrists and were suffering from neurotic anxiety. Evaluation for therapeutic efficacy used a clinical global improvement scale and the Hamilton Anxiety Scale. Evaluation for side effects used the side effects symptoms check list. Anxiolytic effects of prazepam and lorazepam are not significantly different. Tolerance of the two treatments is comparable. The side effects are essentially an undesirable sedative action.

Adolescent↗
PubMed1978

Prazepam in the treatment of anxiety: a placebo-controlled multicenter evaluation.

A double-blind randomized multicenter parallel group comparison of prazepam in divided doses vs. placebo was conducted by 15 investigators among 847 patients presenting with anxiety alone or concurrent with other medical illnesses. Study groups were well matched for age, sex and level of pre-treatment symptomatology. Efficacy evaluation by a physician questionnaire included serial assessment of global improvement plus 10 target signs/symptoms during the 2 to 4 weeks of treatment. Prazepam was statistically significantly superior to placebo as shown on final on-treatment scores for global improvement ratio and for the target symptoms of anxiety, tension, irritability/hostility, depressive mood, insomnia and somatization.

Adolescent↗
PubMedDate not supplied

[Comparative double-blind study of bromazepam versus prazepam in non-psychotic anxiety].

The efficacy of bromazepam and prazepam for the different components of anxiety: inhibition, asthenia and somatisation is evaluated in a multi-centric, comparative and randomised study, conducted as double blind and in parallel groups in 159 adult patients showing a manifest anxiety according to the F.D.A. criteria. After a 7 day wash-out period, the patients receive either bromazepam in a 12 mg/d dose or prazepam in a 40 mg/d dose, over 4 weeks (D0-D28), then in a decreasing dose from D28 to D43; follow-up is carried out using the anxious inhibition scale W.P.2, auto-questionnaire A.D.A., the Hamilton anxiety scale and the Tyrer questionnaire (benzodiazepine withdrawal symptoms questionnaire). Patients are evaluated seven times during the study: at day 7 for inclusion, day 0 for randomisation, then day 7 and day 14 for following visits, at day 28 for efficacy and tolerance evaluation, and at day 50 for utilisation and withdrawal evaluation. The major efficacy criteria are the evolution of inhibition, asthenia and somatisation as compounds of anxiety respectively evaluated by W.P.2 scale, asthenic partial score of autoquestionnaire A.D.A. and somatic partial score of Hamilton anxiety scale. The analysis of results don't show any significant difference between the two groups on the evolution of the components asthenia and inhibition. However the evolution of the somatic component clearly makes a significant difference in favour of bromazepam. There is also a significant difference in terms of global anxiolytic action efficacy, in favour of bromazepam.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1981

A comparison of prazepam, diazepam, lorazepam and placebo in anxious outpatients in non-psychiatric private practices.

A double-blind, random design, parallel group, four-week study of prazepam, diazepam, lorazepam, and placebo was conducted in diverse private outpatient practices (surgeon, internist, and obstetrician-gynecologist) using a common protocol, in order to evaluate their comparative efficacy in these settings. In addition, the effects of these anxiolytics on depressive symptoms in patients with anxiety were studied. Results showed that the non-psychiatric practitioners used lower dosages than psychiatrists in previous reports, and perception of anxiety levels of their patients were lower than the psychiatric raters. When patients were divided into two groups (1. predominantly depressed with anxiety, and 2. predominantly anxious with depression), differences between the benzodiazepines were shown. In the high depression-low anxiety group, all four treatment methods were effective in alleviating both anxiety and depression. In the high anxiety-low depression group, only prazepam and placebo were effective in alleviating both anxiety and depression, while diazepam and lorazepam decreased anxiety levels, but not depression.

Adolescent↗
PubMed1998

Kinetic study on the degradation of prazepam in acidic aqueous solutions by high-performance liquid chromatography and fourth-order derivative ultraviolet spectrophotometry.

A reversed-phase HPLC method was developed for the kinetic investigation of the acidic hydrolysis of prazepam which was carried out in hydrochloric acid solutions of 0.01, 0.1 and 1.0 M. In addition, a fourth-order derivative method for monitoring the parent compound itself was proposed and evaluated. One intermediate was observed by HPLC, which should be formed from breakage of the azomethine linkage. Further slow hydrolysis of the amide bond led to the benzophenone product that was isolated and identified. The mechanism of hydrolysis was biphasic, showing a consecutive reaction with a reversible step. Relative standard deviation was less than 2% for HPLC and less than 5% for the derivative method. Detection limits were 1.2 x 10(-7) M for the former method and 6.7 x 10(-7)M for the latter. Accelerated studies at higher temperatures were employed. Results of HPLC and fourth-order derivative methods were statistically the same.

Anti-Anxiety Agents↗
PubMed1980

Desmethyldiazepam kinetics in the elderly after oral prazepam.

Our subjects were 15 young (aged 22 to 42 yr) and 14 elderly (aged 62 to 85 yr) people who took single oral doses of 20 mg prazepam. Plasma desmethyldiazepam (DMDZ) concentrations were determined in venous blood samples drawn up to 9 days after the dose. Appearance in blood of DMDZ was slow, with peak plasma levels reached in an average of 10 to 20 hr. First-order DMDZ appearance was observed in only 17 subjects. Volume of distribution of total DMDZ (range, 1.33 to 6.30 l/kg) and of unbound DMDZ after correction for protein binding (range, 43 to 243 l/kg) was larger in women than in men of all ages, and in the elderly as opposed to the young. Elimination half-life (range, 29 to 224 hr) rose with age in men (r = 0.66, p < 0.01) but not in women (r = -0.02). Clearance of unbound DMDZ (range, 2.9 to 31.2 ml/min/kg) was greater in women than in men of all ages, and declined with age in men (r = -0.40) but not in women (r = -0.06). As in the case of diazepam, age can influence DMDZ kinetics, but changes in drug disposition with age may differ between sexes.

Adult↗
PubMed1991

Compared efficacy of prazepam and clomipramine in major depression with anxiety: a multicenter controlled study.

UNLABELLED: The efficacy of antidepressants is well established in major depressions, especially those with melancholic features. However, some anxiolytics also appear to have antidepressant properties at least for outpatients. 118 outpatients (25 males, 93 females, age: 18-60) with major depression according to DSM-III criteria, neither melancholic nor suicidal, reaching at least 27 on Montgomery and Asberg depression rating scale (MADRS) and 19 on Hamilton anxiety rating scale (HARS) accepted to participate this double blind study carried out by 15 G.P.s coordinated by 3 psychiatrists. After a one week placebo wash-out-single-blind period, they were randomly, double blind, assigned to one of the two following groups: PR treated with prazepam (30-60 mg), a benzodiazepine anxiolytic or CL treated clomipramine, an imipramine antidepressant (75-150 mg). Patients were evaluated at days 0, 7, 14, and 28, using MADRS, HARS, Clinical Global Impression and Hopkins symptoms check list 58. In addition, G.P.s had to meet monthly for a case discussion group. RESULTS: groups were comparable at day 0. A highly significant improvement of MADRS and HARS scores (p less than 0.001) was observed in the total population. For the completer population evolution was also significantly positive in all the parameters studied but, considering MADRS and HSCL scores, a difference in favor of CL is observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1978

[Synthesis of 14C-labelled prazepam (author's transl)].

In order to study the metabolic fate of prazepam (PZ), a new synthetic method of [5-14C]PZ(I) and [sidechain-14C]PZ (II) was investigated. The synthesis of these labelled compounds has already been described by E. J. Merrill, et al., but their method requires many synthetic steps and the yield is unfavorably poor. We have recently found much more convenient and efficient method, which is summarized below. 2-Iodo-4-chloroaniline was cyanized with Cu14CN obtained from K14CN, then reacted with phenylmagnesium bromide, hydrolyzed with conc. HCl to give [carbonyl-14C]2-amino-5-chloro-benzophenone(ACB). ACB was bromoacetylated, aminated with NH3 in MeOH, then heated and cyclized to [5-14C]desalkylprazepam(DPZ) according to the usual procedure. DPZ was converted to its Na salt with MeONa, then reacted with cyclopropylmethyl bromide in DMF to give I (2.61 mCi/mmol) with the overall yield of 41.9% from K14CN. [5-14C] Diazepam was also obtained by using MeI instead of cyclopropylmethyl bromide. On the other hand, 14CO2 generated from Na214CO3 and H2SO4 was reacted with cyclopropylmagnesium bromide to give [carboxyl-14C]cyclopropanecarboxylic acid, which was reduced with LiAlH4, then naphthalenesulfonylated to [alpha-14C]cyclopropylmethyl 2-naphthalenesulfonate. Na salt of DPZ was treated with the naphthalenesulfonate in DMF to give II (3.45mCi/mmol) with the overall yield of 36.9% from Na214CO3.

Carbon Radioisotopes↗
PubMed1992

Acute poisonings with ethyle loflazepate, flunitrazepam, prazepam and triazolam in children.

Even though acute poisonings with benzodiazepines are extremely common, less is known of the clinical toxicity of recent derivatives, particularly in children. 1,989 cases involving ethyle loflazepate, flunitrazepam, prazepam or triazolam recorded at the Lyons Poison Center and due to 1 compound and associated with clinical symptoms were selected for study. Children less than 16-y of age accounted for 482 cases. Sleepiness, agitation and ataxia were significantly more frequent in the children. Hypotonia was seldom observed but was indicative of severe poisoning. The dangerous toxic dose of these compounds in children is suggested to be 0.78-0.90 mg ethyle loflazepate/kg, 0.26-0.29 mg flunitrazepam/kg, 7.80-9.00 mg prazepam/kg and 0.06-0.07 mg triazolam/kg. These results are in keeping with the relatively low acute toxicity of the older benzodiazepines.

Adolescent↗