Effect of age and sex on disposition of desmethyldiazepam formed from its precursor clorazepate

Desmethyldiazepam (DMDZ) disposition was evaluated in 32 healthy male and female volunteers who ingested single 15-mg doses of the precursor compound, clorazepate dipotassium. DMDZ concentrations were measured in multiple plasma samples obtained between 7 and 9 days after dosage. Appearance of DMDZ in blood was rapid, with peak concentrations attained on average 1.5 h after dosage. Absorption half-life (t1/2 a) averaged 24 min. Neither peak time nor t1/2 a were influenced by age or sex. After a rapid phase of distribution, DMDZ elimination was slow, with a mean elimination half-life (t1/2 beta) of 82 h (range 27-219 h). t1/2 beta became prolonged with age in men but not in women. Likewise, clearance of total (free bound) DMDZ declined with age in male subjects (r=- 0.47, P less than 0.1), but was unrelated to age in women. DMDZ was extensively bound to protein in all subjects. The mean free fraction (FF) was 3.1% (range 2.0-4.3%), and increased significantly with declining plasma albumin concentrations (r=-0.57, P less than 0.001). Partly due to a decline in plasma albumin with age (r=-0.47, P less than 0.01), FF tended to increase with age (r=0.23). After correction for individual differences in FF, clearance of pharmacologically active unbound DMDZ declined significantly with age in men (r=-0.65, P less than 0.01), but actually was slightly higher in elderly as opposed to young women. Thus, the age-related decline in the capacity for hepatic hydroxylation of DMDZ is highly sex-specific.

Effect of magnesium--aluminum hydroxide and kaolin--pectin on absorption of digoxin from tablets and capsules

Twelve healthy fasting volunteers received two 0.2-mg digoxin capsules or tablets with 60 ml water, 60 ml Maalox, or 60 ml Kaopectate in a randomized, single-dose, six-way crossover study. Concentrations of digoxin in multiple plasma samples and in all urine collected during the 24 hours after each dose were determined by radioimmunoassay. Compared to the water treatment, administration of both tablets and capsules with Maalox or Kaopectate reduced the peak digoxin plasma concentrations but did not significantly influence the time of peak concentration. Neither Maalox nor Kaopectate influenced the area under the 24-hour plasma concentration--time curve for either tablets or capsules. However, 24-hour urinary recovery of digoxin from tablets tended to be reduced by Maalox and Kaopectate; this was not the case with capsules. Digoxin capsules may have an advantage over currently available tablets in clinical situations requiring digoxin coadministration with nonabsorbable gastrointestinal preparations.

Plasma diazepam and desmethyldiazepam concentrations during long-term diazepam therapy

1 Factors influencing steady-state plasma concentrations of diazepam (DZ) and its major metabolite desmethyldiazepam (DMDZ) were assessed in 110 male Veterans Administration outpatient clinic patients (mean age 53 years). 2 Patients reportedly had taken DZ for 1 to 14 years (mean duration 5.1 years) at a mean daily dose of 20 mg (range 2 to 55 mg). 3 Steady-state plasma concentrations of DZ (mean 329 ng/ml) and DMDZ (mean 389 ng/ml) were highly correlated (r = 0.80), with a mean DMDZ/DZ ratio of 1.26. 4 Weight-corrected daily dose were significantly correlated with plasma level of DZ (r = 0.32), DMDZ (r = 0.38) and the sum of DZ plus DMDZ (r = 0.37), but explained a small fraction of individual variation. 5 Duration of therapy, smoking habits, alcohol consumption, and number of other drugs coingested were not significantly related to plasma level.

Benzodiazepines: a summary of pharmacokinetic properties

1 The onset and duration of action of benzodiazepines after single oral doses depend largely on absorption rate and extent of distribution, respectively. 2 The rate and extent of accumulation during multiple dosage depend on elimination half-life and clearance. A framework is proposed for classification of benzodiazepines according to elimination half-life. 3 Long-acting benzodiazepines have half-life values usually exceeding 24 hours. Drugs in this category have long-acting pharmacologically active metabolites (often desmethyldiazepam), accumulate extensively during multiple dosage, and may have impaired clearance in the elderly and those with liver disease. 4 Intermediate and short-acting benzodiazepines have half-life values from 5-24 hours. Active metabolites are uncommon. Accumulation during multiple dosage is less extensive than with the long-acting group, and diminishes as the half-life becomes shorter. Age and liver disease have a small influence on metabolic clearance. 5 The half-life of ultrashort acting benzodiazepines is less than 5 hours. These drugs are essentially non-accumulating. 6 Pharmacokinetic classification may assist in understanding of differences among benzodiazepines, but does not explain all of their clinical actions.

Oxazepam kinetics: effects of age and sex

Thirty-eight healthy male and female volunteers, 22 to 84 years of age, ingested single 30-mg doses of oxazepam tablets in the fasting state. Oxazepam plasma concentrations were determined by electron-capture gas-liquid chromatography in multiple samples drawn during 48 hr after the dose. Absorption of oxazepam was relatively slow with peak plasma levels reached an average of 2 to 3 hr after dosage. First-order absorption was observed in only 22 of the 38 subjects. Elimination half-life ranged from 4.9 to 19.4 hr and was longer (P < .05) in females (mean: 9.7 hr) than in males (7.8 hr). Half-life was not associated with age in males but tended to increase with age in females (r = 0.45). Oxazepam was extensively bound to plasma protein. The mean free fraction was 4.3% and did not differ between sexes. Free fraction tended to increase with age (r = 0.25), in part because of significantly lower plasma albumin concentrations in the elderly (r = -0.58). Assuming 100% systemic availability, clearance of total as well as unbound oxazepam was significantly greater in men than in women. Intrinsic clearance tended to decline with age in men (r = -0.21) and women (r = -0.24) but these associations were not significant. Higher oxazepam clearance was associated with heavy cigarette smoking but this did not explain the sex-related difference. Thus, sex is a more important determinant of oxazepam clearance than is age.

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.

Diazepam disposition determinants

Factors influencing diazepam kinetics were assessed in 4 equal groups (n = 11) of young male and female (aged 21 to 37 yr) and elderly male and female (aged 61 to 84 yr) subjects, all of whom were healthy. In all 44, plasma diazepam concentrations were determined by electron-capture gas-liquid chromatography in multiple samples drawn for as long as 9 days after a single 5- to 10-mg intravenous dose. Based upon total (bound + free) diazepam concentrations, volume of distribution (Vd) ranged from 0.7 to 4.7 l/kg, and became larger both with increasing age and with female sex. Clearances of total (bound + free) diazepam in young and elderly females were nearly identical (0.51 and 0.48 ml/min/kg), but clearance was higher in young than elderly males (0.39 and 0.24 ml/min/kg, p less than 0.01). The unbound fraction of diazepam in plasma (range, 0.9% to 2.7%) did not depend on sex, but was greater in the elderly than in the young. In part this related to lower plasma albumin concentrations in the elderly. After correction of kinetic data for individual differences in free fraction, Vd was larger in the females than in the males, but the effect of age was small. Clearance of unbound diazepam (intrinsic clearance) tended to be higher in the females than in the males of both age groups, and was higher in the young than in the elderly of both sexes (male: 29.9 and 14.9 ml/min/kg, p less than 0.005; female: 43.6 and 28.0 ml/min/kg, p less than 0.05). Smoking was associated with higher clearance values, particularly among young subjects.

Overdosage with pentobarbital and secobarbital: assessment of factors related to outcome

Factors related to clinical outcome following acute overdosage with pentobarbital or secobarbital were assessed in a series of 162 patients hospitalized during the period 1962 to 1975. The mean ingested dose was 2 Gm (range 0.2 to 10.0 Gm), and plasma barbiturate concentrations ranged from 2.0 to 72.0 microgram/ml. Serious intoxication was common. Intubation and assisted ventilation were required in 59 per cent of patients, and 23 per cent developed clinically important hypotension. Four patients died, all relatively young females. Multiple regression and discriminant function analyses, performed on a subset of 88 patients for whom complete data were available, indicated that plasma barbiturate concentration and/or ingested dose were the most important correlates of serious intoxication among identifiable variables available on admission. Coingestion of other central nervous system depressants, such as ethanol, had no obvious effect on outcome. The present study suggests that measurement of plasma barbiturate concentrations is of value in identifying patients at risk of developing serious intoxication after overdosage with pentobarbital or secobarbital.

Lorazepam kinetics in the elderly

Lorazepam is a 3-hydroxy-1,4-benzodiazepine derivative biotransformed by glucuronide conjugation, followed by urinary excretion of the glucuronide metabolite. The kinetic properties of single 1.5- to 3.0-mg doses of intravenous lorazepam were assessed in 15 healthy elderly subjects, 60 to 84 yr of age, and in 15 healthy young subjects, 19 to 38 yr of age. Volumes of distribution for lorazepam in the elderly group (mean, 0.99 1/kg), were slightly but significantly smaller than in the young group (1.11 1/kg), suggesting less extensive drug distribution in the elderly. Values of elimination half-life (t1/2beta) in the elderly (15.9 hr) did not differ significantly from those in the young group (14.1 hr), but total clearance in the elderly (0.77 ml/min/kg) was 22% less (p less than 0.05) than in the young subjects (0.99 ml/min/kg). Age differences in lorazepam clearance were partly explained by more frequent cigarette smoking in the young subjects. Gender had no apparent relationship to kinetics. The rate and completeness of absorption of intramuscular (IM) and oral loraxepam was assessed in 10 of the elderly subjects. Deltoid IM injection and oral administration of tablets in the fasting state led to rapid absorption of lorazepam into the systemic circulation. Peak plasma lorazepam concentrations were always reached within 2.5 hr, and values of absorption half-life (t1/2a) did not exceed 45 min. Absorption of IM and oral lorazepam was 80% to 100% complete. Thus, the aging process is associated with small changes in the kinetics of lorazepam. IM and oral administration of lorazepam in elderly persons, as in the case of young individuals, leads to rapid and nearly complete absorption into the systemic circulation.

Diagnosis and lithium treatment of affective disorder in the retarded: five case studies

The authors report on five institutionalized retarded patients who had symptoms strongly suggestive of manic-depressive illness and who showed significant symptom reduction in a single-blind placebo-controlled three-year trial of lithium. The number of illness episodes was reduced, and symptoms decreased in all major illness dimensions. These findings indicate that major affective disorder can be both diagnosed and treated in individuals with primary mental retardation.

Self-rated sedation and plasma concentrations of desmethyldiazepam following single doses of clorazepate

Plasma concentrations of desmethyldiazepam (DMDZ) and intensity of self-rated sedation (SRS) were measured at multiple points in time during 6 h after a single 15 mg oral dose of clorazepate dipotassium. Mean plasma DMDZ levels and mean SRS scores both became maximal at 1.0--2.5 h after drug dosage. By 6 h, however, mean SRS had returned to the predrug baseline score while mean DMDZ concentration fell only slighty from the maximum value. Disappearance of SRS despite persistence of high DMDZ levels might be due to adaptation or tolerance. If this is the case, subjective effects of benzodiazepines may depend upon duration of drug exposure as well as dose and concentration.

Correlates of outcome following acute glutethimide overdosage

Potential predictors of outcome following acute glutethimide overdosage were assessed in 63 patients hospitalized with this diagnosis at a large urban medical center between 1962 and 1975. Their mean age was 34 years (range, 15 to 84 years) and 62% were female. Assisted ventilation was required in 59% of cases, and 32% developed hypotension. Six patients died, including all three aged 60 years or older. Multiple regression analysis confirmed that age was the major identifiable determinant of survival, regardless of other factors. Among identifiable determinants of coma grade, glutethimide dose, glutethimide plasma concentration, and coingestion of barbiturates were the most important. An ingested dose of 10 g or more, or a plasma concentration exceeding 30 microgram/ml, was almost always associated with deep coma. However, a relatively small ingested dose or a low plasma level by no means ruled out development of serious intoxication, particularly in those patients who also ingested barbiturates. Thus elderly individuals are at high risk for fatal outcome following glutethimide overdosage and should receive priority for intensive care and monitoring. Glutethimide dose, plasma concentration, and history of coingestion of barbiturates are of value in predicting development of deep coma. These items of information should be obtained on admission whenever possible.

Pharmacokinetics of chlordiazepoxide and metabolites following single and multiple oral doses

Three healthy volunteers (2 male and one female) participated in single- and multiple-dose pharmacokinetic studies of oral chlordiazepoxide (CDX) hydrochloride. Following single 50-mg oral doses of CDX.HCl, absorption and elimination proceeded as apparent first-order processes. Values of absorption half-life were: 14.5, 189, and 18.9 minutes; elimination half-lives were: 7.6, 9.8, and 12.6 hours. Disappearance of CDX was mirrored by appearance of its first active metabolite, desmethylchlordiazepoxide (DMCDX). During once-daily ingestion of 50 mg of CDX.HCl, observed values of CDX accumulation half-life (0.0, 5.8, and 52.5 hours) differed substantially from values predicted based upon the single-dose study; pre-dose steady-state CDX blood concentrations also differed from the predicted values. Accumulation half-lives for the metabolite DMCDX were: 17.7, 9.9, and 15.8 hours. Accumulation in blood of a second active metabolite, demoxepam (DMX), proceeded with half-life values of 21.1, 34.2, and 78.5 hours. Minimum steady-state concentrations of DMCDX and DMX exceeded those of the parent compound. Thus accumulation and persistence of at least two active metabolites during long-term treatment with chlordiazepoxide renders the drug suitable for single-daily dose therapy of anxiety.

Dose-independent pharmacokinetics of digoxin in humans

Nine healthy male volunteers received single 0.5, 1.0, and 1.5 mg. doses of intravenous digoxin in a randomized three-way crossover study. Multiple venous blood samples were drawn during 35 hours after each dose, and all urine was collected for 6 consecutive days. Concentrations of digoxin in serum and urine were determined by radioimmunoassay. Over-all mean values for kinetic variables were: distribution half-life, 0.35 hours; elimination half-life, 27.9 hours; volume of distribution, 5.46 liters/Kg; total clearance, 2.51 ml./min./Kg. The mean projected cumulative urinary excretion of digoxin was 70.1% of the dose; mean renal clearance of digoxin was 1.71 ml./min./Kg., not significantly different from creatinine clearance (1.50 ml./min./Kg.). None of the identifiable pharmacokinetic variables was significantly influenced by dose, suggesting that digoxin disposition is dose-independent in healthy individuals.

Impaired absorption of desmethyldiazepam from clorazepate by magnesium aluminum hydroxide

Ten healthy volunteers ingested single 15-mg doses of clorazepate dipotassium (CZP) with 60 ml of water, or with 60 ml of magnesium aluminum hydroxide (Maalox), on two occasions in a randomized, two-way crossover study. Plasma concentrations of desmethyldiazepam (DMDZ) were determined in multiple samples drawn during 48 hr after each dose. Mean kinetic variables for DMDZ in CZP-water and CZP-magnesium aluminum hydroxide treatment conditions, respectively, were: peak measured concentration, 273 and 188 ng/ml (p 0.001); time of peak concentration, 1.8 and 2.8 hr after dose (p less than 0.01); apparent absorption half-life, 14.8 and 30.7 min (p less than 0.02); area under the 48-hr plasma concentration curve, 6,028 and 5,433 ng/ml X hr (p less than 0.02). Self-rated sensations of feedling "spacey," "thinking slowed down," and of generalized sedation, were reported with both treatment conditions, but these subjective effects occurred earlier and were more profound when CZP was taken with water as opposed to magnesium aluminum hydroxide. Thus administration of single doses of CZP with usual doses of a commonly prescribed antacid reduces the rate and extent of appearance in blood of DMDZ (the compound responsible for clinical activity) and attenuates self-rated clinical effects.

Effect of abdominal radiation therapy on drug absorption in humans

The absorption of oral digoxin and of desmethyldiazepam, from its precursor clorazepate, was studied in seven patients who had received abdominal and/or pelvic radiation therapy for neoplastic disease. All patients were in remission and had normal renal function and no evidence of malabsorption. Single 0.5-mg doses of digoxin tablets and 15-mg doses of clorazepate were administered in the fasting state. Concentrations of digoxin (by radioimmunoassay) and desmethyldiazepam (by gas chromatography) were determined in multiple plasma samples and all urine collected during 24 hours after dosage. The mean (+/- S.E.) weight-normalized area under the 24-hour plasma digoxin concentration curve (WtN-AUC-24) in the patients (722 +/- 40 ng/ml-hr-kg) was similar to that in five normal controls (713 +/- 57 ng/ml-hr-kg), but 24-hour urinary excretion of digoxin in patients (54.5 +/- 4.4 microgram) was significantly less (P less than 0.025) than in controls (83.4 +/- 11.4 microgram). Neither age, sex, nor renal function explained the difference. In the clorazepate study, WtN-AUC-24 for desmethyldiazepam in the patients (187 +/- 19 microgram/ml-hr-kg) was significantly less (P less than 0.01) than in 15 normal control subjects (230 +/- 5 microgram/ml-hr-kg). Age and sex did not explain the difference. Thus, radiation therapy, or the underlying disease, is associated with malabsorption of these two drugs, possibly because of damage to gastric acid-secreting cells.

Factors influencing diazepam pharmacokinetics: age, sex, and liver disease

Published data on the effect of cirrhosis on diazepam pharmacokinetics were reanalyzed to determine how age, sex, and body weight might have influenced the conclusions. Diazepam elimination half-life (t1/2beta) and weight-corrected volume of distribution (Vd) were significantly larger in patients with cirrhosis (n = 9) than in controls (n = 4). Weight-corrected diazepam clearance was significantly reduced in cirrhotics as compared with controls. Multiple stepwise regression analysis, however, revealed that age and liver disease were of approximately equal importance as determinants of t1/2beta. Age, sex, and liver disease all influenced Vd, but liver disease by far was the most important determinant of diazepam clearance. Thus age, sex, and body size can have an important influence on the pharmacokinetics of drugs, and should be included as independent variables in pharmacokinetic studies.

Sex differences in diazepam protein binding in patients with renal insufficiency

Sex differences in the extent of binding of diazepam to plasma protein were assessed in a series of patients with renal insufficiency previously described by Kangas et al. Among identifiable independent variables, sex alone accounted for the greatest proportion of variability in percent unbound diazepam (r = 0.33), whereas age and serum creatinine accounted for practically none. The mean (+/- SE) percent unbound among females (10.8 +/- 2.8%) was larger (p less than 0.1) than among males (5.8 +/- 1.3%). Since only the unbound fraction of diazepam in plasma is available for pharmacologic activity, the intensity and duration of diazepam's clinical action in patients with renal insufficiency might differ between males and females.

Effects of chlordiazepoxide and oxazepam administration on verbal hostility

We compare the effects of chlordiazepoxide, oxazepam, and placebo on hostility, as both an inner motivational or potential state and verbal interpersonal behavior. This article reports the findings relevant to the latter dimension of hostility and integrates them with those findings, presented in an initial report, relevant to hostility as an inner motivational state. The verbal data again support the hypothesis that chlordiazepoxide-induced increases in verbal interpersonal hostility, following frustration, are greater than those associated with placebo. With regard to oxazepam, the verbal hostility data were consonant with the motivational data that suggested that oxazepam does not substantially disinhibit hostility but did not as consistently differentiate oxazepam and chlordiazepoxide at the level of overt hostile behavior.

Factors influencing blood concentrations of chlordiazepoxide: a use of multiple regression analysis

Three groups of male and female subjects aged 24-74 years received 25, 100, or 200 mg of chlordiazepoxide hydrochloride by mouth as a single dose or as two divided doses. The relation of plasma or whole blood concentrations for chlordiazepoxide (CDX) and its metabolite, desmethylchlordiazepoxide (DMCDX), to time since the last dose, weight, age, and sex were determined by simple and multiple regression analyses. Both CDX and DMCDX levels were negatively correlated with weight. Concentrations of CDX decreased, while those of DMCDX increased, with the time since the last dose. Lower levels of both drugs were associated with female sex, and lower levels of DMCDX were noted with increasing age. In the largest sample group, age and weight were more important variables than sex in accounting for CDX and DMCDX. Sex was of significance, and more important than time or age in explaining the variance of CDX in one series of observations. Multiple regression analysis is a useful approach to assessing interrelated factors influencing blood levels of drugs, especially when combined with a consideration of the interactive components of variance. Age and sex, in addition to weight and time, may be important factors that deserve further attention.

Pharmacokinetics and clinical effects of amantadine in drug-induced extrapyramidal symptoms

Plasma amantadine concentrations were assessed in a series of hospitalized schizophrenic patients receiving this drug during a double-blind trial of amantadine and benztropine in the treatment of neuroleptic-induced extrapyramidal symptoms (EPS). Mean (+/- S.E.) plasma amantadine concentrations were 0.54 +/- 0.08 microgram/ml on day 7 and 0.43 +/- 0.08 microgram/ml on day 14. Overall improvement of EPS was not correlated with plasma level, but improvement in the target EPS of rigidity was correlated with plasma amantadine concentration on day 7 (r = 0.75) and day 14 (r = 0.68). There was no evidence that the overall improvement in schizophrenic symptomatology was influenced by plasma amantadine concentrations.

Clinical pharmacokinetics of lorazepam. IV. Long-term oral administration

Fifteen healthy male volunteers received long-term daily treatment with oral lorazepam at doses as high as 10 mg per day for a period of 26 weeks. Steady-state plasma concentrations of lorazepam and its glucuronide metabolite were measured in all subjects at least every two weeks. At daily doses of 6 mg per day, the mean steady-state lorazepam level was 88 ng/ml and that of lorazepam glucuronide was 170 ng/ml. Mean levels among seven subjects who received 10 mg per day were 164 and 266 ng/ml, respectively. Lorazepam concentrations fluctuated from week to week despite constant dosage, but there was no evidence of systematic variation. Mean steady-state lorazepam levels were highly correlated with daily dose in mg/kg, but were not related to age. Lorazepam was not detected in any plasma samples drawn one week after discontinuation of treatment.

Absorption rate, blood concentrations, and early response to oral chlordiazepoxide

Ten healthy male volunteers received chlordiazepoxide (CDX) hydrochloride or matching placebo with Maalox or water in a four-way single-dose crossover trial. Coadministration of CDX with Maalox did not change the completeness of CDX absorption but significantly slowed its rate of absorption and the rate of desmethylchlordiazepoxide (DMCDX) appearance. Self-rating of feeling "spacey" at 1.0 and 2.5 hours were significantly increased over baseline for CDX taken with water but not with Maalox. Increases in "spacey" feelings at 1.0 hours were highly correlated with 0.5-hour but not with 1.0-hour blood levels. Similar findings were observed for self-ratings of "thinking" slowed down. Thus certain subjective effects of antianxiety agents after oral dosage may depend on the rate of drug absorption and may be attenuated or eliminated if the absorption rate is reduced.

Pharmacokinetic approach to the clinical use of lidocaine intravenously

The time course of lidocaine plasma concentrations following various modes of administration were predicted by computer. Initiating therapy with a single intravenous bolus dose was unsatisfactory; plasma levels during the first hour were potentially toxic after a 200-mg bolus and subtherapeutic after a 50- to 100-mg bolus. After two bolus doses of 100 mg, separated by 20 to 30 minutes, or a rapid loading infusion over 15 to 60 minutes, therapeutic concentrations were achieved and maintained. Pharmacokinetic principles can be of value in devising rational approaches to lidocaine dosage.

Variability of 24-hour urinary creatinine excretion by normal subjects

Creatinine excretion was studied in eight healthy males who collected 54 to 97 24-hour urine specimens. Significant differences among subjects in mean creatinine excretion were only partly explained by differences in body weight and surface area. Considerable daily within-subject variation in creatinine excretion during normal activity was found. Standard deviations were from 10.5 to 14.4 per cent of the mean, and ranges varied from 50 to 79 per cent of the mean. Day-to-day variation appeared to be time dependent rather than entirely random, and could not be explained by unreliability of the assay technique or by incomplete collections. Creatinine excretion values were normally distributed in seven of eight subjects. Individual variation from day to day limits the value of urinary creatinine excretion as an index of the completeness of 24-hour urine collections.

Influence of magnesium and aluminum hydroxide mixture on chlordiazepoxide absorption

Ten healthy male subjects ingested 25 mg of chlordiazepoxide hydrochloride (Librium) with 100 ml of water or with 100 ml of magnesium and aluminum hydroxide (Maalox) in a single-dose crossover study. Multiple venous blood samples drawn during the first 24 hr after each dose were assayed for concentrations of chlordiazepoxide and its major metabolite, desmethylchlordiazepoxide. The antacid prolonged the mean chlordiazepoxide absorption half-time from 11 to 24 min, and in 6 of 10 subjects delayed achievement of the peak blood concentration by from 0.5 to 3.0 hrs. The formation of desmethylclordiazepoxide was also slowed. The areas under the 24 hr blood concentration curve for chlordiazepoxide and for its metabolite were not influenced by the antacid. The apparent elimination half-life of chlordiazepoxide (8.4 and 8.2 hr) was not significantly affected. Administration of chlordiazepoxide with antacid reduces the rate of its absorption but does not alter the completeness of absorption or the apparent rate of elimination.

The differential effects of chlordiazepoxide and oxazepam on hostility in a small group setting

The authors compared the effects of chlordiazepoxide, oxazepam, and placebo on hostility, as an inner motivational or arousal state, in moderately and highly anxious male research volunteers. The data again supported the hypothesis that clordiazepoxide-induced increases in motivational hostility are more frequent and intense than those associated with placebo and oxazepum. The data also suggest that oxazepam may be a more specific "hostility tranquilizer" than other benzodiazepines.

Psychopharmacologic investigations in healthy elderly volunteers: MMPI depression scale

The Depression Scale of the Minnesota Multiphasic Personality Inventory (MMPI) was used as a screening test for healthy volunteers in a psychopharmacologic research study. Data were collected on 43 men and 46 women under age 35 versus 33 men and 43 women over age 65 (plus a subsequent group of 40 men over age 65), and comparisons were made with more extensive data from the Mayo Clinic. The evidence indicates that elderly subjects differ strikingly from young subjects in their responses to items in the MMPI self-ratings of depression. Revised information on normative responses is needed. At present there are too many problems of interpretation when the Depression Scale items are applied to t.he elderly.

Psychopharmacologic investigations in healthy elderly volunteers: effects of pipradrol-vitamin (Alertonic) elixir and placebo in relation to research design

Ninety-nine healthy elderly volunteers were tested to assess the effects of: 1) a pipradrol-vitamin (Alertonic) elixir, 2) a placebo, and 3) no treatment, during a one-week period. The assessment measures were the Minnesota Multiphasic Personality Inventory Depression Scale, the Zung Depression Scale, Profile of Mood States, and the WAIS Digit Span. Alertonic had no sigmificant effects on mood, memory or appetite, and the placebo effect was rarely greater than 50 per cent. There were no significant side effects. The findings demonstrate a valid method for studying psychotropic agents in the elderly.