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PubMed1982

Relationship between plasma corticosterone and adrenal epinephrine after diazepam treatment in rats.

Following recent observations that diazepam treatment increases adrenal epinephrine in rats, we were interested in studying the possible mechanisms of this action of diazepam on rat adrenal glands. All diazepam treatments studied (1-25 mg . kg-1.day-1 for 10 days) led to an increase in adrenal epinephrine following a linear dose-effect relationship. Since epinephrine synthesis is under neuronal and humoral controls, we investigated their respective importance in the effect of diazepam on the adrenal gland. The denervation of the adrenal gland did not prevent the increase in adrenal epinephrine by diazepam treatment. On the hand, diazepam treatment was shown to cause an increase in plasma corticosterone in parallel with an increase in adrenal epinephrine. Administration of dexamethasone (a synthetic corticoid) and hypophysectomy prevented the increase in adrenal epinephrine and plasma corticosterone resulting from diazepam treatment. We thus conclude that the increase in adrenal epinephrine seen after diazepam treatment is parallel to the increase in plasma corticosterone. Moreover, since the action of diazepam on adrenal epinephrine is prevented by dexamethasone or hypophysectomy, we hypothesize that diazepam is acting on the adrenal cortex via the release of adrenocorticotropic hormone (ACTH). ACTH and corticosterone would be responsible for the increased activity of epinephrine-synthesizing enzymes in adrenal medulla.

Adrenal Glands↗
PubMed2001

Diazepam stimulates migration and phagocytosis of human neutrophils: possible contribution of peripheral-type benzodiazepine receptors and intracellular calcium.

In isolated human neutrophils, diazepam (10 nmol/l to 10 micromol/l) concentration-dependently increased migration and phagocytosis. Diazepam-induced migration and phagocytosis were inhibited by the peripheral benzodiazepine receptor (PBR) antagonist PK11195 (10 micromol/l). The PBR agonist Ro5-4864 (10 nmol/l to 10 micromol/l) did not affect migration but slightly enhanced phagocytosis, while clonazepam, which binds to the central-type benzodiazepine receptors but has no affinity for PBRs, was ineffective on both parameters up to 10 micromol/l. Phagocytosis induced by diazepam or Ro5-4864 was inhibited by the Ca2+ channel blocker L-verapamil (10 micromol/l), which however did not affect the action of diazepam on migration. Competition binding experiments performed by fluorescent staining of PBRs showed that diazepam directly interacts with PBRs on human neutrophils. Both diazepam and Ro5-4864 (10 nmol/l to 10 micromol/l) induced a rise of intracellular free Ca2+ concentrations ([Ca2+]i), which was inhibited by PK11195 (10 micromol/l) and L-verapamil (10 micromol/l) and prevented by extracellular Ca2+ chelation with EGTA (5 mmol/l). In conclusion, experimental evidence indicates that in human neutrophils diazepam stimulates both migration and phagocytosis through activation of PBRs. Diazepam-induced [Ca2+]i changes depend on a PBR-operated, L-verapamil-sensitive increase in the plasma membrane permeability and subsequent extracellular Ca2+ entry, and contribute to diazepam-induced phagocytosis. On the contrary, the effect of diazepam on migration seems to occur through Ca2+ -independent mechanisms.

Calcium↗
PubMed1999

Effect of diazepam on survival of the immature pig in a confined atmosphere.

Diazepam is known to prolong survival in an atmosphere containing 5% oxygen, and to reduce cerebral metabolic rate and cerebral perfusion. It also depresses the arousal response to hypoxia and protects the optic nerve from anoxia. We hypothesised that diazepam might extend survival in a confined atmosphere with a limited amount of oxygen. Pigs consumed the oxygen in a sealed chamber until they reached the terminal state. The experimental pigs (n = 6) were sedated with diazepam 0.3 mg/kg i.v. and were compared with a control group (n = 5). We measured blood pressure, inspired O2 and CO2, minute ventilation, ECG, ambient and body temperatures, and PO2, PCO2, O2 content and pH in arterial and venous blood. In the diazepam-treated pigs, oxygen consumption was reduced in the hypoxic range (PIO2 below 60 torr) compared with the control pigs. Diazepam prevented the elevated hypoxic cardiac output found in the control pigs. There were almost no differences between the diazepam and control groups in the other parameters measured in the course of the exposure and in the terminal state. Terminal PIO2, PaO2, and PvO2 were 36.9 +/- 5.6, 27.9 +/- 8.6, 14.3 +/- 2.0 torr, and 36.9 +/- 5.7, 23.7 +/- 7.3, 15.7 +/- 7.6 torr in the diazepam and control groups, respectively. The survival time was 220 +/- 51 and 255 +/- 50 min in diazepam and control pigs, respectively. In spite of its anticonvulsant effect and the fact that it protects CNS white matter from anoxia, prolongs anoxic survival and eliminates the high oxygen demand in hypoxic arousal, diazepam failed to extend hypoxic survival in a confined atmosphere to a lower PIO2. However, diazepam had no deleterious effect on survival, and may therefore be used to ease stressful hypoxic conditions.

Animals↗
PubMed1999

[Effect of diazepam on fetus after intravenous administration during the active phase in labour].

To investigate the effects of diazepam on fetal heart rate and Apgar scoring administered intravenously during the active phase in labour, sixty-two normal term parturients during the active phase of labour with the cervical dilation to 3-5 cm were randomly divided into two groups, diazepam group (n = 32) and control group (n = 30). In diazepam group, 10 mg diazepam was administered intravenously. The concentrations of diazepam in maternal and cord serum were measured by high performance liquid chromatography after birth and the fetal heart rates were monitored by electronic monitor before or after administration of diazepam and Apgar scores were determined immediately after birth. The results showed that the mean level of diazepam in umbilical cord serum was markedly higher than that of maternal serum. Fetal heart base line mutation in diazepam group was weaker than that of the control group. Apgar scores in the neonates of diazepam group was lower than those of the control group. The results indicate that the use of diazepam in pregnant women during active phase of labour may cause depression of fetus.

Adult↗
PubMedDate not supplied

Determination of diazepam in cream biscuits by liquid chromatography.

An analytical procedure was developed for the detection and quantitation of diazepam in cream biscuits, which were used to commit crime. The method involves the extraction of diazepam with ethanol at room temperature, and the extract is filtered, evaporated to dryness, and redissolved in the mobile phase, methanol-acetonitrile-tetrahydrofuran-water (15 + 55 + 4 + 26, v/v). The separation is achieved on a C18 reversed-phase column with the mobile phase and diode array detection (lambda(max)) at 230 nm. Medazepam is used as the internal standard is for quantification. The calibration plot for the determination of diazepam is based on linear regression analysis (y = 0.6687x + 0.0372; r2 = 0.995). The limit of detection for diazepam in the biscuit samples was estimated as 600 ng/mL. The limit of quantitation for diazepam was estimated as 1.75 microg/mL. The diazepam detected per piece of biscuit was found to be in the range of 0.27-0.45 mg. Pure diazepam was added to biscuit samples at 3 levels (100 and 500 microg/g, and 1 mg/g), and the recoveries were found to be 95%. The mean retention time of diazepam was 2.7 min and that of medazepam (IS) was 4 min. The relative standard deviations of the diazepam level in the biscuit samples were estimated to be 0.4% for retention time and 1.02% for peak area in intraday analysis, whereas the corresponding values were and 0.61 and 2.34% in interday analysis. The method is rapid and reliable for qualitative and quantitative analysis of cream biscuits laced with diazepam, and it can be used by law enforcement laboratories for routine analysis.

Anti-Anxiety Agents↗
PubMedDate not supplied

Tissue distribution of 14C-diazepam and its metabolites in rats.

We have kinetically investigated the tissue distribution of 14C-diazepam and described the appearance and disappearance of its metabolites (3-hydroxydiazepam, desmethyldiazepam, and oxazepam) following a single iv injection of 14C-diazepam into rats. Significant amounts of oxazepam were detected in plasma and various tissues in the rat, contrary to previous reports. Concentration-time profiles of diazepam in the main disposing organs (liver, kidney, and lung) and the other organs (brain, heart, and small intestine) indicated that diazepam was distributed rapidly to these organs. Concentration-time profiles of diazepam in the main tissues for drug distribution (skin and adipose) indicated that diazepam was slowly distributed to these tissues, whereas that in muscle, which is also responsible for drug distribution, indicated that diazepam was less rapidly distributed to this tissue. Metabolites appeared in plasma and various tissues or organs immediately after iv injection of diazepam. Metabolites levels in plasma and various tissues or organs were significantly lower than that of diazepam except for liver and small intestine, where metabolites levels were higher compared to that of diazepam and metabolites exhibited a considerable persistence.

Adipose Tissue↗
PubMed1983

Physical dependence on diazepam and lorazepam in the dog.

Dogs, surgically implanted with a gastric fistula, were chronically dosed with diazepam or lorazepam. Diazepam (60 mg/kg/day) or lorazepam (100 mg/kg/day) was administered intragastrically in four divided daily doses. Beginning no less than 2 weeks after the attainment of stabilization doses, dogs underwent withdrawal experiments, repeated at 2-week intervals. At a time of withdrawal determined by a Latin square crossover design, dogs were observed for 8 hr for signs of abstinence. Both diazepam and lorazepam caused a withdrawal abstinence syndrome to appear upon abrupt discontinuation of the drug. The two abstinence syndromes had many signs in common, including tremor, hot foot walking, rigidity and decreased food intake, but the lorazepam withdrawal abstinence syndrome was much less intense and had a shorter latency to onset than the diazepam abstinence syndrome, which also included clonic and tonic-clonic convulsions and was lethal in two dogs. Furthermore, the diazepam withdrawal abstinence syndrome was biphasic, the first phase apparent by 24 hr and a second phase beginning at 48 hr, whereas the lorazepam syndrome was not. Diazepam suppressed the major signs of diazepam abstinence in a dose-related manner, but failed to completely suppress all signs of abstinence. CGS-8216, a pyrazoloquinoline benzodiazepine antagonist, precipitated abstinence in the diazepam-dependent dog, but did not precipitate tonic-clonic seizures. No abstinence syndrome was precipitated in the lorazepam-dependent dog. These results would suggest that whereas diazepam and lorazepam both cause physical dependence the two syndromes are not the same and, furthermore, that physical dependence on, and withdrawal from, diazepam involves at least two separate mechanisms with different selectivity for benzodiazepine agonists and antagonists.

Animals↗
PubMed1980

Drug modification of ECT: methohexital and diazepam. II.

A systematic comparison of methohexital and diazepam as anesthetics in the drug modification of ECT was done by holding atropinizaton, succinylcholine-depolarizing neuromuscular blockade, and resuscitation constant while monitoring four ECT in each of 24 patients. Each patient served as his own control, and two dosages of each drug (0.25 and 0.35 mg/kg diazepam, 0.9 and 1.1 mg/kg methohexital) were given each patient in all possible orderings (4! = 24) in a scheduled experimental design in which methohexital was given by very rapid (5 sec) and diazepam was given by the recommended slower (60 sec) infusion. The data revealed significant differences and methohexital was superior. Eight of 48 (17%) EKGs were abnormal post-ECT with methohexital, 18 of 48 (38%, phi = 5.3, p < 0.025) with diazepam. Five of 24 (21%) patients had an abnormal post-ECT EKG with methohexital, 15 of 24 (60%, phi 8.6, p < 0.005) with diazepam. Significantly more ventricular premature contractions (VPCs) occurred after diazepam. Diazepam records contained both more numerous and more extensive EKG abnormalities. Methohexital induction was clinically superior as well; there was little of the induction restlessness seen in seven treatments with diazepam (phi2 7.6, p < 0.01). The differences were less marked than in a previous study in which diazepam was given as rapidly as methohexital. Methohexital has been demonstrated to be the anexthesia of safety and choice for ECT when compared to diazepam.

Diazepam↗
PubMed1993

Effect of the chronic dose of diazepam on the intensity and characteristics of the precipitated abstinence syndrome in the dog.

The ability of different chronic doses of diazepam to produce dependence was studied in groups of six dogs who received diazepam p.o. (0.05625, 0.225, 0.5625, 4.5, 9 or 36 mg/kg/day) every 8 hr. After 5 to 6 weeks of stabilization, the intensity of precipitated abstinence was measured by benzodiazepine-precipitated abstinence scores (BPAS) after the p.o. administration of graded doses of the benzodiazepine antagonist, flumazenil (0.66, 2, 6, 18, 36 and 72 mg/kg or a placebo). A modified Latin square design was used. Dogs receiving the two lowest stabilization doses of diazepam showed only liminal signs of precipitated abstinence even with 72 mg/kg of flumazenil. The intensity of the precipitated abstinence syndrome increased with the stabilization dose of diazepam. There was also a dose-related increase in BPAS for increasing doses of flumazenil for all doses of diazepam except the 9-mg/kg/day dose. Not only were quantitative differences observed in precipitated abstinence signs for different levels of diazepam dependence, but the pattern of abstinence signs differed also. Dogs dependent on high doses of diazepam were more sensitive to flumazenil than those dependent on lower doses. Furthermore, seizure activity was seen only in dogs dependent on 9 and 36 mg/kg/day of diazepam. BPAS increased linearly with plasma and brain total and free levels of the sum of diazepam and its metabolites (oxazepam and nordiazepam), but not with free plasma and brain levels of diazepam.

Animals↗
PubMed1995

Absorption of diazepam after its rectal administration in dogs.

A cross-over study was performed in 6 healthy mixed-breed dogs and 4 healthy Beagles. Diazepam was administered per rectum to Beagles (0.5 mg/kg of body weight) and mixed-breed dogs (2 mg/kg), and IV (0.5 mg/kg) to both groups of dogs. Each dog received the drug by both routes, with a 1-week washout period between dosages. After diazepam administration, blood samples were collected to measure plasma concentration of diazepam and its active metabolites, desmethyldiazepam and oxazepam, by use of reverse-phase high-performance liquid chromatography (HPLC). Systemic availability was assessed by comparing the area under the curve for diazepam metabolites for each route of administration. Mean (+/- SD) diazepam concentrations in plasma after rectal administration were low in comparison with those obtained after IV administration, with systemic availability of only 7.4 (+/- 5.9) and 2.7 (+/- 3.2)% for the high and low dose, respectively. However, diazepam was converted to its metabolites within minutes after administration. Accounting for the total concentration of benzodiazepines (diazepam plus desmethyldiazepam and oxazepam) in plasma, systemic availability was 79.9 (+/- 20.7) and 66.0 (+/- 23.8)% for the high and low dosage, respectively. After IV administration, diazepam concentration decreased, with a half-life of only 14 to 16 minutes, but desmethyldiazepam and oxazepam concentrations decreased more slowly, with a half-life of 2.2 to 2.8 hours and 3.5 to 5.1 hours, respectively. Each of the metabolites is reported to have anticonvulsant activity. After rectal administration of the high dose, mean total benzodiazepine concentration was above 1.0 microgram/ml within 10 minutes and was maintained above this concentration for at least 6 hours. We conclude that diazepam is absorbed after rectal administration in dogs, and that the pharmacologic effects are probably caused by the active metabolites, not the parent drug. Samples also were analyzed by use of a nonspecific commercial benzodiazepine fluorescence polarization immunoassay (FPIA). Correlation between the FPIA and HPLC assay was strongest for diazepam (R2 = 0.84), weak for desmethyldiazepam (R2 = 0.09), and nonexistent for oxazepam. We conclude from a comparison of assays that HPLC is preferred over the FPIA method for measuring benzodiazepines in dogs.

Absorption↗
PubMed2004

Diazepam for treating tetanus.

BACKGROUND: Clinical management of the muscle spasms and rigidity of tetanus poses a difficult therapeutic problem to physicians everywhere, especially in resource poor countries. There are wide variations in therapeutic regimens commonly used in clinical practice due to uncertainties about effectiveness of conventional drugs. Diazepam compared to other drugs (eg phenobarbitone and chlorpromazine) may have advantages because of combined anticonvulsant, muscle relaxant, sedative and anxiolytic effects. OBJECTIVES: To compare diazepam to other drugs in treating the muscle spasms and rigidity of tetanus in children and adults. SEARCH STRATEGY: We searched the Cochrane Neonatal Group trials register (October 2003), Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2003), MEDLINE (1966 to October 2003), EMBASE (1980 to October 2003), LILACS (2003), CINAHL (October 2003), Science Citation Index, African Index Medicus, conference abstracts and reference lists of articles. We contacted researchers, experts and organizations working in the field and used personal communication. SELECTION CRITERIA: Randomized and quasi-randomized controlled trials. DATA COLLECTION AND ANALYSIS: We independently identified eligible trials, assessed trial methodological quality and extracted data. MAIN RESULTS: Two studies met the inclusion criteria. Method of generation of allocation sequence, concealment of allocation and blinding were unclear in both studies. A total of 134 children were allocated to three treatment groups comprising diazepam alone, phenobarbitone and chlorpromazine, or phenobarbitone and chlorpromazine and diazepam.Meta-analysis of in-hospital deaths indicates that children treated with diazepam alone had a better chance of survival than those treated with combination of phenobarbitone and chlorpromazine (Relative Risk for death 0.36; 95% confidence interval 0.15 to 0.86; Risk Difference -0.22; 95% CI -0.38 to -0.06). Giving diazepam alone, or supplementing conventional anticonvulsants (phenobarbitone and chlorpromazine) with diazepam, was reported in one study to be associated with a statistically significantly milder clinical course and shorter duration of hospitalization. REVIEWER'S CONCLUSIONS: Although there is evidence that diazepam alone compared with combination of phenobarbitone and chlorpromazine is more effective in treating tetanus, the small size, methodological limitations and lack of data on drug safety from available trials preclude definite conclusions to support change in current clinical practice. The application of the present evidence should be moderated by local needs and circumstances, pending the availability of more evidence. We recommend a large multicenter, randomized controlled trial which compares diazepam alone with combinations of other drugs (excluding diazepam).

Anticonvulsants↗
PubMed1986

Interaction of diazepam with famotidine and cimetidine, two H2-receptor antagonists.

Famotidine is currently under investigation as an H2-receptor antagonist. Eleven healthy male volunteers received a single 10 mg intravenous dose of diazepam on three occasions: once during coadministration of famotidine 40 mg bid, once during coadministration of cimetidine 300 mg qid, and once without other drug treatment (control). Multiple blood samples were drawn during the seven days after each diazepam dose. Diazepam and desmethyldiazepam plasma concentrations were measured by electron capture gas chromatography. There were no significant differences among the three treatment conditions in diazepam central compartment volume or total volume of distribution. During the cimetidine as compared with the control treatment, diazepam elimination half-life was significantly increased (72 vs 55 hr, P less than .05), total area under the curve (AUC) increased (11.8 vs 9.8 hr-micrograms/mL, P less than .05), and total clearance reduced (0.20 vs 0.28 mL/min/kg, P less than .05). Seven-day AUC for desmethyldiazepam also increased (4.6 vs 3.8 hr-micrograms/mL, P less than .05). However, there were no significant differences between famotidine and control treatment conditions in diazepam elimination half-life (53 vs 55 hr), total AUC (9.5 vs 9.8 hr-micrograms/mL), or total clearance (0.28 vs 0.28 mL/min/kg) or in seven-day AUC for desmethyldiazepam (3.9 vs 3.8 hr-micrograms/mL). Thus, therapeutic doses of cimetidine significantly impair the clearance of diazepam and desmethyldiazepam. Therapeutic doses of famotidine do not impair diazepam and desmethyldiazepam kinetics, suggesting that there is no significant kinetic interaction when diazepam and famotidine are administered concurrently in clinical practice.

Adult↗
PubMed1987

Imipramine treatment alters the pharmacokinetics and pharmacodynamics of diazepam.

This report describes observations of the relationship between the pharmacokinetics and pharmacodynamics of diazepam (7-chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one ; 5 mg/kg) during the concomitant administration of diazepam and imipramine hydrochloride (5-[3-(dimethylamino)propyl]-10,11-dihydro-5H-dibenz[b,f]azepine monohydrochloride; 20 and 50 mg/kg) to rats. We measured plasma, brain, and liver concentrations of diazepam and its metabolites in rats by high-performance liquid chromatography. The concomitant use of imipramine hydrochloride increased diazepam and desmethyldiazepam concentrations, but decreased temazepam and oxazepam concentrations in rat plasma. Diazepam plasma protein binding was unaltered. The liver concentrations of diazepam and its metabolites showed similar changes in their plasma concentrations. The concomitant use of imipramine hydrochloride increased the concentrations of diazepam and its metabolites in the brain. We also studied the effect of benzodiazepines on convulsions induced by pentylenetetrazole (6,7,8,9-tetrahydro-5H-tetrazolo[1,5-a] azepine; 135 mg/kg) in rats. The concomitant use of imipramine hydrochloride led to an increased antipentylenetetrazole effect of diazepam. This result is in accordance with the findings on brain concentrations of diazepam and its metabolites.

Animals↗
PubMed1995

Infusions of diazepam and allopregnanolone into the midbrain central gray facilitate open-field behavior and sexual receptivity in female rats.

We have previously shown that blocking GABAA receptors with bicuculline in the dorsal and lateral quadrants of the rostral two-thirds of the midbrain central gray (MCG) in rats reduces the lordosis quotient (LQ) and proceptive behaviors without increasing the defensive index (McCarthy, Pfaff, and Schwartz-Giblin, 1991b), indicating that tonic release of endogenous GABA in the MCG has a primary facilitatory effect on reproductive behaviors. The present study tests whether two modulators of the GABAA-benzodiazepine-receptor complex, diazepam and the progesterone metabolite, allopregnanolone, facilitate female receptivity as well as open-field behavior. Ovariectomized estradiol benzoate (EB)-treated rats were bilaterally infused in the MCG with vehicle, diazepam, or allopregnanolone and tested 20 min after diazepam and 12 min after allopregnanolone. Animals were tested once each for both receptive or open-field behavior with testing sessions being at least 1 week apart in a crossover design between vehicle and one of the two drugs. Both diazepam and allopregnanolone significantly increased the lordosis quotient in a dose-dependent manner, the lowest effective dose tested being 100 and 250 ng, respectively. In the open-field test, infusion of diazepam (100 ng) in EB-treated rats significantly increased the ratio of central squares entered to total squares entered (C/T) without a change in total activity. Rats without EB elicited comparable C/T ratios when tested with five times as much diazepam. Diazepam infusions at more dorsal sites in the midbrain and in overlying cortex were without effect on C/T ratios in EB-treated rats. Allopregnanolone (500 ng) infusions in MCG of EB-treated rats did not alter C/T ratios compared to animals without EB. Our results are consistent with diazepam and allopregnanolone acting through the GABAA receptors of the MCG to enhance female sexual receptivity and with estradiol potentiating the effect of diazepam in the MCG to increase open-field behavior.

Animals↗
PubMed1992

The interactions of ethanol with single and repeated doses of suriclone and diazepam on physiological and psychomotor functions in normal subjects.

The effects of diazepam (5 mg t.i.d.), suriclone (0.2 and 0.4 mg t.i.d.) and placebo (t.i.d.) were assessed in 12 normal, healthy volunteer subjects after a single dose and after treatment for a period of 8 days. A battery of physiological, psychomotor and subjective tests was administered on days 1 and 8 both before and after drug and after a measured dose of ethanol. The effects of diazepam on the EEG were characteristic of benzodiazepines-a decrease in the slow frequency wave-bands, an increase in fast frequency wave-band and diminished evoked response amplitude. Suriclone had similar effects on fast frequency activity and evoked response amplitude but, in contrast to diazepam, also increased the slow frequency wave-bands after 7 days treatment. Some improvements in performance were seen with suriclone on critical flicker fusion, tapping speed, spiral maze and digit cancellation. In contrast, suriclone impaired performance to a greater extent than diazepam on digit symbol substitution and symbol copying. Body sway was also enhanced by suriclone to a greater extent than diazepam. Subjective ratings for mood and adverse-effects showed few differences between suriclone or diazepam. However, suriclone caused greater gastro-intestinal disturbances than diazepam, especially after ethanol, and subjects rated themselves as more antagonistic and more irritable on suriclone. Ratings for calmness suggested that in contrast to diazepam, suriclone had no anxiolytic effect. Several of the parameters tested showed a build up of effect with diazepam over the treatment period which was not seen with suriclone. It is suggested that this difference may be due to differences in elimination rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Application of the axial dispersion model of hepatic drug elimination to the kinetics of diazepam in the isolated perfused rat liver.

The application of the axial dispersion model to diazepam hepatic elimination was evaluated using data obtained for several conditions using the single-pass isolated perfused rat liver preparation. The influence of alterations in the fraction unbound in perfusate (fu) and perfusate flow (Q) on the availability (F) of diazepam was studied under steady conditions (n = 4 in each case). Changes in fu were produced by altering the concentration of human serum albumin (HSA) in the perfusion medium while maintaining diazepam concentration at 1 mg L-1. In the absence of protein (fu = 1), diazepam availability was 0.011 +/- 0.005 (mean +/- SD). As fu decreased, availability progressively increased and at a HSA concentration of 2% (g/100 ml), when fu was 0.023, diazepam availability was 0.851 +/- 0.011. Application of the axial dispersion model to the relationship between fu and F provided estimates for the dispersion number (DN) of 0.337 +/- 0.197, and intrinsic clearance (CL(int)) of 132 +/- 34 ml min-1. The availability of diazepam during perfusion with protein-free media was also studied at three different flow rates (15, 22.5, and 30 ml min-1). Diazepam availability always progressively increased as perfusate flow increased, with the axial dispersion model yielding estimates for DN of 0.393 +/- 0.128 and CL(int) of 144 +/- 38 ml min-1. The transient form of the two-compartment dispersion model was also applied to the output concentration versus time profile of diazepam after bolus input of a radiolabeled tracer into the hepatic portal vein (n = 4), providing DN and CL(int) estimates of 0.251 +/- 0.093 and 135 +/- 59 ml min-1, respectively. Hence, all methods provided similar estimates for DN and CL(int). Furthermore, the magnitude of DN is similar to that determined for noneliminated substances such as erythrocytes, albumin, sucrose, and water. These findings suggest that the dispersion of diazepam in the perfused rat liver is determined primarily by the architecture of the hepatic microvasculature.

Animals↗
PubMed1991

The effect of intravenous diazepam on esophageal motility in normal subjects.

Controversy exists over whether diazepam can be used for sedation during esophageal manometry studies without affecting the results. To evaluate the effect of diazepam, 20 healthy asymptomatic volunteers were studied using a standard manometry protocol employing an Arndorfer capillary infusion system. Following a baseline manometry, each subject received 0.1 mg/kg diazepam intravenously over 1 min and underwent repeat manometry 5 min after completion of the injection. All manometry recordings were coded and read blindly. The amplitude of the lower esophageal sphincter was significantly reduced by diazepam from 26.2 +/- 10.9 and 30.0 +/- 10.9 mm Hg to 18.8 +/- 7.6 and 24.5 +/- 9.7 mm Hg by rapid and station pull-through methods, respectively (P less than 0.01 both methods). Esophageal contraction wave duration was significantly increased following diazepam at 3, 8, and 13 cm above the lower esophageal sphincter (P less than 0.01 all levels). There was a trend toward increased contraction wave amplitude following diazepam administration in the lower three fourths of the esophagus. On the basis of these results, we conclude that diazepam sedation may produce misleading results when used during esophageal manometric testing. It is recommended that diazepam not be used in manometric studies of normal subjects or patients with reflux esophagitis and that manometric findings in patients with hypertensive or spastic disorders be interpreted with caution if diazepam is given as a premedication.

Adult↗
PubMed1979

[Impairment of performance by alcohol and diazepam (author's transl)].

An investigation was carried out on the effect of the intake of diazepam and alcohol on simple performance tests. The combined administration of diazepam and alcohol led to an increase of the plasma diazepam concentration as compared to that obtained after diazepam without alcohol. Furthermore, after combined intake of diazepam and alcohol a decrease of performance was observed, that was significantly higher, than the effects obtained after either alcohol or diazepam alone. This impairment was especially noticeable duirng the first hour of the experiment, i.e. until the plateau of the diazepam plasma concentration was reached, while afterwards a correlation between diazepam plasma concentration and impairment of performance could not be established. The relevance of these findings for the interpretation of diazepam plasma concentrations in relation to the impairment of performance are discussed.

Achievement↗