Subject(s)
Antiparkinson Agents/administration & dosage , Carbidopa/administration & dosage , Infusion Pumps/statistics & numerical data , Levodopa/administration & dosage , Parkinson Disease/drug therapy , Aged , Dose-Response Relationship, Drug , Drug Administration Schedule , Duodenum/drug effects , Duodenum/metabolism , Dyskinesia, Drug-Induced/prevention & control , Female , Follow-Up Studies , Humans , Male , Middle Aged , Time , Time Factors , Treatment OutcomeABSTRACT
The pharmacokinetics of two benzodiazepine hypnotics, flunitrazepam and loprazolam, was determined on two occasions in two groups of eight healthy volunteers. Single 2-mg oral doses of either drug were given in the fasting state at morning on one occasion and after a standard dinner at night on another. Compared with administration of drugs in the fasting state, administration of the drugs after dinner decreased peak plasma concentrations, delayed the time to reach maximum concentration, and prolonged the absorption half-life. The extent of absorption was reduced for flunitrazepam but not for loprazolam. The elimination half-life of both flunitrazepam and loprazolam was not changed in the two conditions. These changes may be of clinical significance because they can delay and reduce the effects of the drugs.
Subject(s)
Anti-Anxiety Agents , Benzodiazepines , Benzodiazepinones/pharmacokinetics , Eating , Flunitrazepam/pharmacokinetics , Administration, Oral , Adult , Benzodiazepinones/administration & dosage , Benzodiazepinones/blood , Flunitrazepam/administration & dosage , Flunitrazepam/blood , Half-Life , Humans , Male , Time FactorsABSTRACT
The kinetics of a single 1-mg oral dose of chlordemethyldiazepam (CDDZ, En) was determined on two occasions in 8 healthy volunteers. CDDZ was given in the fasting state on one occasion and following a standard meal on another. Compared with the fasting state, administration of CDDZ with food prolonged the time to reach peak concentration (1.5 vs. 6.8 h after dosage, p less than 0.01) and the absorption half-life (28 vs. 231 min, p less than 0.01). Total area under the curve was not influenced, nor was CDDZ elimination half-life (84.2 vs. 88.7 h). Thus administration of CDDZ with food slows the rate of its absorption but does not alter the completeness of absorption.
Subject(s)
Anti-Anxiety Agents/pharmacokinetics , Benzodiazepines , Diazepam/analogs & derivatives , Food , Intestinal Absorption , Nordazepam/analogs & derivatives , Adult , Chromatography, Gas , Half-Life , Humans , Male , Nordazepam/pharmacokineticsABSTRACT
Six healthy, fasting volunteers were given single doses of chlordesmethyldiazepam by 1 mg i.v., or as drops or tablets. Chlordesmethyldiazepam and its metabolite, lorazepam, in multiple plasma samples and in urine collected for 120 h after each dose were determined by electron-capture GLC. Mean kinetic variables for intravenous chlordesmethyldiazepam were: volume of distribution, 1.71 l.kg-1; elimination half-life, 113 h; total clearance, 0.21 ml.min-1.kg-1; cumulative excretion of lorazepam glucuronide 24.2% of the dose. Following a lag time of 15.5 min (tablets) and 4.2 min (drops), which were significantly different, the absorption of oral chlordesmethyldiazepam was a first order process, with apparent absorption half-life values averaging 1.5 h (tablets) and 1.1 h (drops). Bioavailability was 77% for tablets and 79% for drops.
Subject(s)
Anti-Anxiety Agents/pharmacokinetics , Benzodiazepines , Diazepam/analogs & derivatives , Nordazepam/analogs & derivatives , Absorption , Administration, Oral , Adult , Anti-Anxiety Agents/administration & dosage , Anticonvulsants/administration & dosage , Anticonvulsants/blood , Anticonvulsants/pharmacokinetics , Anticonvulsants/urine , Biological Availability , Half-Life , Humans , Injections, Intravenous , Male , Nordazepam/administration & dosage , Nordazepam/blood , Nordazepam/pharmacokinetics , Nordazepam/urine , Random Allocation , Tablets , Time FactorsABSTRACT
The pharmacokinetics of chlordemethyldiazepam--a pharmacologically very active new 1,4-benzodiazepine derivative--in healthy subjects after administration of a single oral dose of 2 mg, was studied. Peak concentrations were reached in 1.2 +/- 0.2 hours. Plasma levels declined with a biphasic pattern, and the elimination phase had a half-life of 82.9 +/- 14.1 hours. The concentrations of the main metabolite of chlordemethyldiazepam, lorazepam, were about 7% of those of the parent compound. In urine only conjugated lorazepam could be found its 96 hour excretion reaching about 15% of the administered dose of parent drug.
Subject(s)
Anti-Anxiety Agents , Benzodiazepines , Diazepam/analogs & derivatives , Nordazepam/analogs & derivatives , Administration, Oral , Adult , Half-Life , Humans , Kinetics , Lorazepam/metabolism , Male , Mathematics , Nordazepam/administration & dosage , Nordazepam/metabolismABSTRACT
The kinetics of delorazepam (chlordesmethyldiazepam; CDDZ), and its major metabolite, lorazepam (LRZ) during multiple-dose therapy have been evaluated in two groups of patients with primary or secondary anxiety. The 12 patients in group 1 were 46.8 +/- less than 13.2 years while the eight in group 2 were significantly older (69.7 +/- 7.8 years). All patients were given 0.5 mg twice daily of CDDZ for 30 days. Concentrations of CDDZ and LRZ in multiple blood samples collected during the study were determined by electron-capture gas-liquid chromatography. The degree of anxiety was evaluated from the Hamilton rating scale for anxiety (HRSA). CDDZ and LRZ accumulated in plasma but the rate of accumulation of CDDZ was slower than expected from studies in young volunteers and the half-life values were significantly related to age. Steady-state levels of glucuronated LRZ were also lower in elderly patients. Data indicate that CDDZ is more slowly eliminated and less metabolized as age increases. While pre-treatment scores of HRSA were similar in the two groups, older patients improved significantly less than those of group 1 and had also an higher incidence of side-effects. CDDZ levels positively correlated with improvement in group 1 but not in group 2.
