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Autoimmune thyroid disease, characterized by the presence of specific anti-thyroid antibodies, is the most common cause of thyroid dysfunction and can lead to either hypo- or hyperthyroidism. In rare cases, thyroid function spontaneously shifts from one extreme to the other. A 32 year old man with an 8 year history of hypothyroidism was referred to our clinic for evaluation of hyperthyroidism. He had been on levothyroxine (LT4) replacement, requiring up to 300 µg qd until about 6 months before coming to our attention, when he sustained a 60 lb weight loss. TSH was suppressed and the LT4 dose was progressively decreased to 75 µg qd. On presentation, the patient was clinically euthyroid. He had no family history of thyroid disease. No thyromegaly was noted. Eye exam showed conjunctival injection without proptosis, chemosis, periorbital edema or abnormal extraocular movements. TSH was

Study Objectives Severe sleep restriction results in elevated evening cortisol levels. We examined whether this relative hypercortisolism is associated with alterations in the pituitary-adrenocortical response to evening corticotropin-releasing hormone (CRH) stimulation. Methods Eleven subjects participated in 2 sessions (2 nights of 10 hours vs. 4 hours in bed) in randomized order. Sleep was polygraphically recorded. After the second night of each session, blood was sampled at 20-minute intervals from 09:00 to 24:00 for adrenocorticotropic hormone (ACTH) and cortisol measurements, and perceived stress was assessed hourly. Ovine CRH was injected at 18:00 (1 µg/kg body weight). Results Prior to CRH injection, baseline ACTH, but not cortisol, levels were elevated after sleep restriction. Relative to the well-rested condition, sleep restriction resulted in a 27% decrease in overall ACTH response to CRH (estimated by the incremental area under the curve from 18:00 to 24:00; p = .002) while the cortisol response was decreased by 21% (p = .083). Further, the magnitude of these decreases was correlated with the individual amount of sleep loss (ACTH: rSp = -0.65, p = .032; cortisol: rSp = -0.71, p = .015). The acute post-CRH increment of cortisol was reduced (p = .002) without changes in ACTH reactivity, suggesting decreased adrenal sensitivity. The rate of decline from peak post-injection levels was reduced for cortisol (p = .032), but not for ACTH. Scores of perceived stress were unaffected by CRH injection and were low and similar under both sleep conditions. Conclusions Sleep restriction is associated with a reduction of the overall ACTH and cortisol responses to evening CRH stimulation, and a reduced reactivity and slower recovery of the cortisol response.

Diltiazem, as well as other calcium entry blockers, is widely prescribed for the treatment of various types of angina. This review summarizes the current state of knowledge of the pharmacokinetics of diltiazem and of two other calcium entry blockers: verapamil and nifedipine. Although unrelated in their chemical structure, these three drugs have common features. They are highly lipophilic and have a large volume of distribution, are mainly cleared by metabolism and undergo an extensive first-pass extraction. On the other hand, as expected from their quite dissimilar structures, they have their own particular kinetic characteristics. For example, metabolism of diltiazem and verapamil gives rise to active metabolites; repeated administration influences the kinetic profile of verapamil but not those of diltiazem and nifedipine. Absorption, distribution and elimination of these three drugs are differently affected by age and pathological conditions. The possible drug interactions involving diltiazem and the other calcium entry blockers are discussed, particularly that with digoxin. Due to its large therapeutic index, there is no need for treatment monitoring of diltiazem. Nevertheless, this procedure may provide useful information for optimizing the dosage regimen of each patient as the pathological condition and drug therapy may be quite complex.

This is a randomised, double blind, cross-over, placebo-controlled study carried out in 12 healthy young male volunteers. It consisted of six test days separated by two week wash-out periods. The objective was to compare the potential sedative effects of 3 single oral doses of alpidem (50 mg, 100 mg and 200 mg) versus diazepam (10 mg and 15 mg). Pharmacodynamics were assessed by objective psychometric tests (critical flicker fusion, choice-reaction time, manual dexterity, digit span) and subjective evaluation (visual analogue scales) before then 2 h, 4 h, 8 h and 24 h post-dose. Alpidem in dosages of 50 mg and 100 mg did not impair alertness or psychomotor performance; with 200 mg, psychometric tests and visual analogue scales demonstrated sedative effects 2 h post-dose. In contrast, diazepam in a therapeutic dosage (10 and 15 mg) produced similar impairments of vigilance and psychomotor performance as alpidem 200 mg, indicating a lack of dissociation between anxiolytic and sedative effects.

The diagnosis, course, and therapeutic management of the benzodiazepine withdrawal syndrome is still a debated question. The correct method for clinical trials in this indication is also not yet codified. A large sample of patients is required, so the trial must be conducted on a multicenter basis. The present paper describes the main features of a protocol aimed at investigating the ability of a new nonbenzodiazepine anxiolytic drug, alpidem, in preventing or treating the benzodiazepine withdrawal syndrome. A pretrial to standardize the diagnostic and evaluation criteria to be used in the multicenter trial is described.

SUMMARY: In a double-blind, cross-over trial, progabide (PGB) and placebo were compared as add-on therapy in 59 patients with moderate to severe epilepsy. Eight patients did not complete the study, 4 because of adverse drug reactions (elevation of liver transaminases, 2; gastritis, 1; and acute psychosis, 1) and 4 because of administrative reasons. Among the remaining 51 patients, seizure frequency was reduced >50% in 18 patients with PGB treatment and in 8 patients with placebo (p

The possible clinical significance of plasma level monitoring of psychotropic drugs in psychotic patients is described. In particular, data obtained with children and 'resistant' psychotic patients are presented. The results in children indicate the existence of a good relationship between side-effects and haloperidol plasma levels as well as between adverse effects and chlorimipramine plasma levels. Furthermore, an age effect on haloperidol clearance could be shown. Relationship between haloperidol and chlorimipramine concentration and effects could be observed for tics and enuresis respectively but not for psychotic reactions. Data in adult patients illustrate on the one hand possible causes of variability in plasma levels of haloperidol and, on the other hand, the fact that poor bioavailability is not the cause of lack of response in 'resistant' schizophrenic patients.

Twenty two pregnant women with mild to moderate hypertension were treated with betaxolol (10-40 mg/day), a cardioselective beta adrenoceptor blocking agent. The analysis of the changes from the baseline confirmed the antihypertensive effect of the drug with a mean decrease in SBP of 11.8 mm Hg and in DBP of 8.3 mm Hg. A diastolic BP less than 90 mm Hg was obtained in 20 patients after the first day of therapy. Fetal safety, assessed by ultrasonography and cardiotocographic recording was excellent. The 22 mothers gave birth to 23 live born babies (one twin pregnancy). Mean Apgar scores were 8.3 and 9.1 at 1 and 5 min. Only 1 newborn had an Apgar score less than 7. Three newborns suffered from fetal distress and 1 from threat for causes not related to therapy. At 9 months follow-up, all 23 babies were in good health. These data suggest that betaxolol is effective in reducing maternal blood pressure without any deleterious effect on the foetus and the newborn.

Betaxolol levels in blood were monitored in the perinatal period in 28 pregnant hypertensive women and in their babies. In the mothers betaxolol concentrations at delivery ranged from less than 1 to 115 ng.ml-1 after doses of 10 to 40 mg.day-1. The apparent blood half-life was 15.6 to 22.1 h mean (19 h). Umbilical cord levels indicated a rapid equilibrium between fetal and maternal units (ratio 0.93) within few hours after dosing. Milk betaxolol concentrations, measured in few cases, exceeded those in blood by a factor of 3. Amniotic fluid concentrations were similar to those observed in maternal venous blood and umbilical cord blood. In neonates, the blood betaxolol half-life ranged from 14.8 to 38.5 h, with a definite trend towards a negative correlation with gestational age. A 11-61% rise in the betaxolol concentration was observed in 64% of the neonates during the first 12 h of extrauterine life. The data indicate that betaxolol kinetics is not altered in pregnant women and they stress the need for careful and prolonged (72-96 h) intensive monitoring of neonates born to hypertensive mothers treated with beta-blocking agents.

Summary Objective ALS is the most common motor neurone disorder in human adults. Scanty data on endocrine abnormalities have been reported. The aim of the present study was to investigate the GH-IGF-I axis in ALS patients. Patients Tw enty-two ALS patients (12 men, 10 women), mean age 61 years, and 25 normal age- and sex-matched subjects. No patient was under riluzole therapy. Measurements Patients and controls underwent a GHRH plus arginine test. IGF-I was determined at baseline. A complete evaluation of pituitary function was also performed. Results Mean ( ± SD) basal GH levels were significantly reduced compared with normal controls (0·2 ± 0·3 vs 1·6 ± 1·8 ng/ml, P < 0·01), as well as peak GH concentrations after GHRH + arginine administration (12·6 ± 8·9 vs 39·9 ± 18·7 ng/ml, P < 0·001). Six (27%) patients showed a normal GH response to stimulus; 7 (32%) patients displayed a moderate GH deficiency; in 9 (40%) patients GH response was markedly deficient. IGF-I levels were normal in the majority of patients (mean ± SD: 143·6 ± 63·8 ng /ml). No significant correlation was observed between peak GH concentrations and age, BMI, disease duration, severity or clinical form. A higher incidence of GH deficiency was observed in male compared to female patients (83% vs 60%), with a peak GH response in males significantly lower than in females (8·9 ± 6·6 vs 17 ± 9·6 ng/ml, P = 0·03). Eighteen patients repeated the test after 5 months and similar results were obtained. Conclusions The present data indicate a reduction of GH secretion in ALS patients.

The attempt has been made to define the optimal dose regimen of clonazepam in newborns suffering from neonatal convulsions. Results obtained from 22 patients (GA 28-41 weeks; PNA 4 h to 23 days) indicated that a dose of 0.1 mg/kg every 24 h was satisfactory in the majority of the patients. It is recommended as a starting regimen.

In a parallel-group, placebo-controlled, polysomnographic study with randomization, the possible occurrence of rebound insomnia was evaluated in 24 patients suffering from moderate to severe chronic insomnia and receiving either triazolam 0.5 mg, zolpidem 10 mg, or placebo. Treatment duration was 27 nights, followed by three placebo-controlled withdrawal nights. Both drugs showed significant efficacy compared to placebo during the active treatment period. A trend toward tolerance was noted in the triazolam group but not in the zolpidem one. The increase in total sleep time in the zolpidem group was accompanied by an increase in the number of sleep cycles. When active treatment was discontinued, clear rebound insomnia was present in the triazolam group while it was not possible to observe any rebound in the placebo and zolpidem groups. Subjective feelings of the patients, which were assessed by means of visual analog scales, correlated well with polysomnographic data. Our findings tend to indicate that, even after long-term treatment, zolpidem does not induce rebound insomnia or daytime anxiety.

Zolpidem is an imidazopyridine which binds specifically to the omega 1 receptor. Zolpidem demonstrated potent hypnotic activity at a dose of 10 mg. Pharmacodynamics and pharmacokinetics of zolpidem were studied after daytime administration in a randomised, double-blind, placebo-controlled, cross-over trial. Single doses of zolpidem (10 mg IV as a 3-min infusion and 20 mg orally) and placebo were firstly tested in 12 healthy young male volunteers. Two other doses (5 mg IV and orally) were then evaluated in 6 out of these 12 subjects. EEG (4 leads = Fp2-T4, Fp1-T3, T4-02 and T3-01), and Stanford Sleepiness Scale (SSS) were measured up to 5 h postdosing. Blood samples were also collected up to 24 h. The time course of the hypnotic activity of zolpidem, assessed by the score obtained on SSS, showed a similar profile whatever the route or the dose administered: slightly earlier onset after IV but sedative scores were reached at 30 min and the effect peaked between 1 and 1.5 h and lasted 4 h in both conditions. The EEG profile of zolpidem was characterised by a decrease of alpha activity and an increase in delta and in beta activity. The effect on beta activity was marked within the first hour and then disappeared. The time course of delta and alpha activities indicated a rapid onset (10 min after IV, 30 min after oral route) and a duration of 3-4 h. The amplitude of these relative EEG changes and their duration were independent of the route of administration and the dose administered. AUC and Cmax increased proportionally to the administered dose and elimination half life (2h), clearance and volume of distribution did not change according to the dose or the route of administration.(ABSTRACT TRUNCATED AT 250 WORDS)

1. Twelve healthy subjects were enrolled in a double-blind placebo controlled cross-over study in order to assess the possible anticholinergic effects of four doses of a new antihistamine compound, mizolastine, compared with hyoscine butylbromide (HBB) used as a reference anticholinergic drug. 2. Although mizolastine, a potent and selective H1-receptor blocker has no affinity for muscarinic receptors and does not antagonize the effects of carbachol in rodents, a study was initiated to investigate its effects on various effectors possessing muscarinic receptors (eye, heart, sweat gland, salivary gland). 3. HBB (40 mg, s.c.) impaired accommodation, decreased salivary flow and inhibited cardiac sinus arrhythmia. Pupil diameter and maximum constriction speed, carbachol-induced skin sweating and Valsalva ratio were unaffected. 4. Mizolastine (5, 10, 20, 40 mg p.o.) did not affect any parameter at any time point, demonstrating a lack of anticholinergic effect.

The safety and efficacy of 10 or 20 mg/day zolpidem, a new hypnotic belonging to the imidazopyridine class, were studied over a 180-day period in 96 patients with sleep disorders. The treatment was continued for a further 180 days by 49 of these patients. Follow-up information from 21 patients who discontinued treatment after 180 days showed no rebound insomnia or withdrawal signs. Efficacy of treatment with respect to reduction of sleep onset latency and number of nocturnal wakenings, and improvement in duration of sleep, quality of sleep and morning wakenings was found in nearly 90% of patients and was maintained in those patients who continued treatment for 360 days. This efficacy was achieved with a stable percentage of patients receiving 10 mg/day and 20 mg/day zolpidem from day 30 to the final visit. Zolpidem, therefore, has been shown to be an effective and safe hypnotic, and to be devoid of rebound and withdrawal effects. La sécurité d'utilisation et l'efficacité du 10 ou 20 mg par jour de zolpidem, un nouvel hypnotique appartenant à la classe des imidazopyridines, ont été étudiées sur une période de 180 jours chez 96 patients souffrant de troubles du sommeil. Le traitement s'est poursuivi pendant 180 jours supplémentaires chez 49 de ces patients. Le suivi de 21 patients ayant cessé le traitement au bout de 180 jours n'a montré ni rebond d'insomnie, ni syndrome de sevrage. L'efficacité du traitement se mesure par la reduction du temp d'endormissement et le nombre de réveils noctures, ainsi que l'amélioration de la durée du sommeil, de la qualité du sommeil et du réveil au matin ont été retrouvés chez près de 90% des patients; ces effets se sont maintenus chez les patients qui ont poursuivi le traitement pendant 360 jours. Cette efficacité a été obtenue pour un pourcentage assez constant de patients qui ont reçu 10 mg par jour de zolpidem, puis 20 mg par jour du 30 ème jour à la fin du traitement. Pour ces raisons, le zolpidem, s'est donc révélé être un hypnotique efficace et sûr, dépourvu d'effets de rebond et de sevrage.

(1992). Comparative Pharmacokinetic Profile of Two Imidazopyridine Drugs: Zolpidem and Alpidem. Drug Metabolism Reviews: Vol. 24, No. 2, pp. 239-266.

Diltiazem undergoes extensive first-pass metabolism; extrapolation from single to repeated administration thus underestimates plasma concentration values. In order to validate the hypothesis of a partially saturable first-pass effect, four single doses of diltiazem (10, 20, 40, and 120 mg) were administered at weekly intervals to eight healthy volunteers. Results showed that: (a) the inter-subject variability was highest at the lowest dose and lowest at the highest dose; (b) bioavailability was almost nil in 3 of 8 of the subjects after the administration of the 10 mg dose; (c) the mean bioavailability increased with the dose from 11·8 ± 2·5 per cent after 10 mg to 28·2 per cent after 120 mg; (d) the elimination half-life was dose-related; (e) the renal excretion of diltiazem increased with the administered dose from 1.0 ± 0·3 per cent after 10 mg to 3·0 ± 0·5 per cent after 120 mg; (f) the greatest amounts of circulating metabolites were present after the lowest doses. These results are consistent with a partially saturable first-pass effect for diltiazem.

Overnight blood sampling for repeated growth hormone (GH) assays, regarded as the most physiological assessment of GH status, may induce some disturbances in patients' sleep and then in the evaluation of GH secretion. We studied the influence of a hypnotic drug, zolpidem (10 mg), on nocturnal GH profiles (GH peak, time to first and maximum GH peak, area under the curve, mean integrated concentration) over two nights at a 7-day interval, in a double-blind cross-over design in a group of 12 young adult volunteers (27.9 +/- 4.3 years), and in a group of 12 children (10.8 +/- 2.3 years) with short stature, in a parallel double-blind study. Mean GH profiles showed no difference between zolpidem-treated subjects and placebo-treated controls, either in adults or in children. Although in these experimental conditions, sleep onset latency was significantly reduced with zolpidem in the adult volunteers, the mean time to first GH peak remained unchanged. Furthermore, GH profile did not relate with sleep duration, sleep onset latency or number of awakenings. A hypnotic drug, such as zolpidem, given at bedtime, is therefore devoided of effect on nocturnal GH profile and may be used in young children for overnight blood sampling when needed.

In a double-blind, placebo-controlled, cross-over experiment in 21 healthy male volunteers, aged 19 to 27 y, the pharmacokinetics and tolerance of the new anxiolytic drug alpidem (SL80.0342) and its three major metabolites were studied after single doses of 25, 50, 100 and 200 mg. Plasma concentrations of alpidem (in 20 subjects) and metabolites (in 6 subjects) were measured by HPLC over a period of 54 h after dosing. Cmax, tmax and AUC(0-54) and, when possible, t1/2 were determined for alpidem and metabolites and the dose linearity of the parameters was investigated. The time to peak of alpidem was dose independent in most subjects and was short (1-4 h); the mean values at the four dosing levels were 1.9, 1.7, 1.6 and 1.8 h. The peak concentration increased with the dose, the mean values being 17, 34, 88 and 115 ng.ml-1, respectively. In 50% of the subjects Cmax tended to stabilize between the 100 and 200 mg dose. Dose linearity was also present for the AUC, which plateaued between the 100 and 200 mg dose in only 3 out of 20 subjects; the mean AUC was 119, 281, 669 and 1117 ng.ml-1.h, respectively. The apparent half-life of elimination appeared to be dose independent, mean values at the increasing dosing levels being 18.7, 19.9, 18.1, and 17.9 h. A similar relationship between the kinetics parameters and dose of the alpidem was observed for the metabolites SL83.0912, SL80.0522 and SL83.0725. The formation of metabolites was not saturated as their AUCs relative to corresponding alpidem AUCs were not dose related.(ABSTRACT TRUNCATED AT 250 WORDS)

The results of a double-blind clinical trial of fengabine vs clomipramine in depressed outpatients are reported. Fengabine, a new GABAergic agent, seems to be as effective as the reference drug, with a faster onset of action and a more marked effect on cognitive disturbances and retardation. The new drug is free of any significant anticholinergic or cardiovascular effect, and it is not sedative.

1. Cicloprolol is a partial beta 1-adrenoceptor agonist considered for the treatment of patients with coronary artery disease and impaired left ventricular function. In such patients, digoxin remains in widespread use. 2. We assessed the pharmacokinetic and pharmacodynamic interaction between oral cicloprolol 50 mg day-1 and oral digoxin 0.25 mg day-1 in 10 healthy male volunteers, using a double-blind, randomised protocol, during three 8 day periods. Digoxin was given alone during the first period to reach steady state; then digoxin was given with cicloprolol or placebo during the second and third periods, according to a cross-over design. 3. No significant adverse effects were observed. 4. The pharmacokinetics of digoxin were not different significantly at the end of the placebo-digoxin and cicloprolol-digoxin periods. 5. A significant increase in minimum heart rate and mean nocturnal heart rate, assessed by 24 h Holter recordings, was observed at the end of the cicloprolol-digoxin period as compared with the placebo-digoxin period (means +/- s.e. mean, 57.1 +/- 3.2 beats min-1 vs 52.2 +/- 3.1 beats min-1, P less than 0.01; and 65.6 +/- 3.8 beats min-1 vs 59.9 +/- 3.9 beats min-1, P less than 0.01, respectively). 6. A significant increase in left ventricular ejection fraction and shortening fraction, assessed by echocardiography, was noted at the end of the cicloprolol-digoxin period as compared with the placebo-digoxin period (means +/- s.e. mean, 66.4 +/- 1.4% vs 61.3 +/- 1.2%, P less than 0.05; and 37.0 +/- 1.1% vs 33.3 +/- 0.9%, P less than 0.05, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

In this double-blind study, alpidem, a new imidazo-pyridine anxiolytic drug, was compared with placebo in order to test its efficacy and safety in chronic schizophrenic in-patients suffering from anxiety not directly related to the schizophrenic process. Sixty-six patients aged from 18 to 65 entered the trial. They also scored at least 18 on the Hamilton Rating Scale for Anxiety (HRSA) after a seven-day placebo run-in. Improvement in symptoms was evaluated by means of the HRSA, the Brief Psychiatric Rating Scale (BPRS), a Visual Analogue Scale (VAS), and the Clinical Global Impression score (CGI). Thirty-three patients were randomly allocated to alpidem and 33 to placebo. Alpidem was significantly more effective (P less than 0.0001) than placebo in improving HRSA scores (total score and factorial scores for somatic and psychic anxiety), BPRS, and VAS. Considering the results of CGI at 21 day, more patients were moderately to markedly improved on alpidem (30/33) than on placebo (2/33) (P less than 0.0001). The efficacy index, according to CGI, was significantly better (P less than 0.001 at least) for alpidem than for placebo. Side-effects were negligible in both groups.

Progabide, a new antiepileptic GABA agonist of moderate affinity for GABA receptors, has been studied in a number of psychiatric disorders and the results compared with the action of this drug in animal models. In an animal model for anxiety (the aversive response to periaqueductal grey stimulation in the rat) progabide had a similar action to that of diazepam. However in clinical trials to date the effect of the GABA agonist was inferior to that of benzodiazepines. As progabide diminishes both the nigrostriatal dopamine neuron activity and the effects of striatal dopamine receptor activation, a trial in schizophrenic patients was undertaken. Progabide was devoid of any evident antipsychotic action. However a certain improvement in responsiveness to the environment and in social interactions was noticed in hebephrenic and shizoaffective syndromes. This lack of antipsychotic effect of progabide may be a reflection of the weak activity of GABA agonists on limbic dopamine neurons. In these various clinical trials a definite improvement of affect and mood was noted in those patients receiving progabide. In clinical trials in depressed patients progabide produces a significant reduction in depressive symptoms, an action similar to that of imipramine both for the global clinical rating and the HRSD. This antidepressant activity is reflected by the action of progabide in behavioural models of depression such as olfactory bulbectomy, learned helplessness and the sleep-wake cycle.

The uptake of imipramine- 14 C, desipramine- 14 C, amitriptyline- 14 C and chlorimipramine- 14 C was studied in rat isolated atria incubated in a medium containing concentrations of the drugs ranging from 10 −8 to 10 −5 M: the tissue levels were linearly related to the concentration in the incubation medium, the four lines sharing almost the same equation: accumulation appeared to be a passive unsaturable process for each drug. Desmethyldoxepin, desmethyl-chlorimipramine, nortriptyline were 4–5 times less potent than desipramine in inhibiting l- 3 H-noradrenaline uptake, while the tertiary amines (imipramine, amitriptyline, chlorimipramine and doxepin) were far less potent. Apart from desipramine, which showed some sympathomimetic activity, the main effect of the drugs was a slowing of the spontaneous atrial rate which was more evident for the dimethyl than for the monomethyl compounds. All drugs potentiated l-noradrenaline chronotropic response to varying degrees, but the potentiation of noradrenaline response was not always correlated with the inhibition of its uptake. Thus, inhibition of uptake is not a valid parameter for prediction of noradrenaline potentiation and vice versa. Drug tissue concentrations correlated with l- 3 H-noradrenaline uptake inhibition but not with potentiation of l-noradrenaline chronotropic response.

Diazepam (DZ) placental transfer in pregnant women at term, following single or repeated drug administration by various routes, was evaluated. DZ and its metabolite N-demethyldiazepam (NDZ) were constantly present in umbilical cord plasma at concentrations comparable to the mother's shortly after drug administration. N-methyloxazepam (MOX) was detected in cord plasma only in a limited number of cases following chronic DZ treatment. Postmortem analysis of fetal tissue concentrations showed accumulation of NDZ in heart and lungs. Differences in NDZ concentrations between venous cord (VC) and arterial cord (AC) plasms suggest metabolic degradation of DZ in the fetus. The DZ apparent plasma half-life in the newborn was found to be longer (31 plus or minus 2 hr) than previously observed in infants and children. The low drug clearance appears to be linked to reduced urinary excretion of hydroxylated metabolites, suggesting limited capability to dispose of DZ in the newborn.

The changes in cerebral blood flow (CBF) during and after bicuculline-induced seizures were studied by the radioactive microsphere technique in 12 newborn, urethan-anesthetized piglets, 6 piglets pretreated with phenobarbital (10 mg/kg) and 6 without phenobarbital. The mean arterial blood pressure (MABP), PaO2, PaCO2 and the cerebral tissue pH (CtpH) were measured. CBF was increased during seizure, more in basal ganglia (98 and 106% in the control and phenobarbital group, respectively) than in brainstem, cerebellum and cortex. 15 min after seizure, CBF has returned to preseizure values. There was no significant difference at any time between the control and phenobarbital group. The increase in CBF was correlated with an increase in MABP (r = 0.753, p less than 0.01), suggesting a loss of cerebral autoregulation. CBF was significantly correlated with PaCO2 before and after seizure, but not during seizure. Finally, the increase in CBF was significantly correlated with an early increase in CtpH (r = 0.570, p less than 0.05), suggesting that brain acidosis is not involved in the pathogenesis of the increased CBF during seizures.

The results of two trials conducted in human dyskinesia with progabide, a specific gamma-aminobutyric acid (GABA) receptor agonist, are reviewed. In one trial, 13 parkinsonian patients with L-DOPA-induced dyskinesia (LDD) and "on-off" fluctuations were included in a double-blind controlled trial progabide versus placebo. No change was observed during this trial in the severity of dyskinesia on progabide treatment but the drug significantly extended the "on" period as compared with placebo. In the second trial, 20 patients with neuroleptic-induced dyskinesia (TD) entered an open dose ranging trial with progabide. Fourteen of the 16 patients who completed the trial had a good-to-excellent therapeutic response. According to these results, progabide does not seem to have the same therapeutic benefit in LDD as TD. These data suggest that the hypothesis of a dopaminergic supersensitivity as a similar pathogenic substrate for both clinical conditions should be reconsidered. If this hypothesis remains the most consistent to explain the occurrence of LDD, the therapeutic effect of progabide in TD is an argument for an implication of the GABAergic system in the appearance of TD.

1. The relationship between plasma concentrations and cardiac effects of nortriptyline was studied in anaesthetized young and old rats. 2. Nortriptyline was administered by two consecutive intravenous infusions which resulted in a peak plasma concentration followed by steady state values. Increasing infusion rates were followed by proportional increases in the drug plasma concentrations ranging from 0.15 to 6.0 microgram/ml. 3. In young rats, nortriptyline induced an increase in the heart rate, a right rotation of the electrical axis and a prolongation of the PQ interval. Heart rate changes were not correlated with nortriptyline plasma concentrations, while significant correlations were found for the other two parameters. Plasma concentrations inducing 20% increase of the PQ interval and 40 degrees rotation of the electrical axis were 1.65 microgram/ml respectively. Arrhythmias occurred at concentrations higher than 5.2 microgram/ml. 4. Nortriptyline caused more severe cardiac effects in old than in young animals. However, plasma concentrations of nortriptyline in old rats were two to five times higher than those found in young rats at similar infusion rates. A higher concentration of the drug at its sites of action seems to be responsible for the more severe cardiac toxicity of nortriptyline observed in old rats.

I.p. administration of d-amphetamine sulphate and fenfluramine · HCl at various doses induced significant modifications of brain noradrenaline (NA) and MOPEG-SO4 (3-methoxy-4-hydrorxyphenylethyleneglycol) in the rat. Both drugs induced a decrease in brain noradrenaline but the two compounds seem to interact with the central noradrenergic system through a different mechanism. The decreased levels of noradrenaline after 1-fenfluramine administration were paralleled by increased MOPEG-SO4 levels. The d-isomer of fenfluramine was less active than the l-isomer. Amphetamine was considerably more effective than 1-fenfluramine in reducing NA concentration. However, in spite of the long lasting effect on noradrenaline levels the i.p. administration of amphetamine did not lead to an increased MOPEG-SO4 concentrations suggesting a more complex interaction with the noradrenergic system.

1 Desipramine and protriptyline were administered to anaesthetized rats by two consecutive intravenous infusions in order to obtain a peak level (first infusion) followed by lower steady state concentrations (second infusion) (Wagner, 1974). Theoretical plasma level time courses were confirmed experimentally.2 Desipramine and protriptyline were measured in atria and ventricles. Increasing infusion rates led to proportional increases in plasma and atrial concentrations. The tissue/medium ratio ranged from 57 to 21 for desipramine and from 43 to 11 for protriptyline according to the time of determination during infusions.3 Heart rate changes, deviation of the electrical axis of the heart and prolongation of atrioventricular conduction were recorded at fixed times during infusion.4 Positive chronotropic effects were noted at plasma concentrations ranging from 0.035 to 0.1 mug/ml for desipramine and from 0.04 to 1.2 mug/ml for protriptyline. At higher plasma concentrations the positive chronotropic effect decreased and bradycardia developed. Both drugs induced right rotation of the electrical axis of the heart. Threshold plasma levels giving 40 degrees rotation were 1.35 mug/ml (desipramine) and 1.75 mug/ml (protriptyline). Atrioventricular conduction was prolonged at threshold plasma concentrations of 2.2 mug/ml for desipramine and 3.6 mug/ml for protriptyline.5 Desipramine is more cardiotoxic than protriptyline. This difference is discussed in relation to the plasma and heart concentration of the two drugs.

The literature data available on pethidine and norpethidine kinetics in women in labour and in their newborns is reviewed and compared with recent personal observations. In pregnant women the apparent blood half-life of pethidine is not different from that in healthy controls, however, apparent volume of distribution and total body clearance are reduced. Norpethidine blood levels are measurable after 10–20 min and tend to increase with time. The amount of drug transferred to the foetus is clearly linked to the dose administered to the mother, the dosing-delivery interval and to the metabolic capability of the mother. An equilibrium between maternal and umbilical venous blood is reached 2–3 h after dosing for pethidine and later for norpethidine. In the neonate, the apparent pethidine half-life is 2 to 7 times longer than in adults with values ranging from 7 to 32 h. Norpethidine is actively formed in the newborn with peak blood levels at 12–36 h and an apparent blood half-life of 20–36 h. At the doses usually recommended blood concentrations at birth are frequently higher than those required for analgesia and close to or within toxic ranges. An effort toward a more individualized dosage as well as toward a better understanding of the possible role of norpethidine with regard to adverse effects is needed.

Patients on long term valproate treatment exhibit unusual fluctuations in steady-state plasma levels of valproic acid. In order to delineate the underlying mechanisms of these fluctuations, 2 studies were undertaken. In the oral study, 6 epileptic patients received enteric-coated sodium valproate tablets (on a bid regimen for at least 1 month) and plasma levels were monitored on an hourly basis during 24 hours. In the intravenous study, 5 patients received first an intravenous bolus dose (800mg) of sodium valproate followed a week later by a combination intravenous loading dose/constant rate infusion for 36 hours. Plasma valproic acid concentrations were monitored hourly during the infusion study. In the oral study, valproic acid concentrations in all subjects continued to decay for 5 to 6 hours following the 8pm dose. The mean fluctuation in concentrations during 24 hours was 112.8 +/- 31.6%. Consecutive fasting levels were not reproducible. In the intravenous study, small but significant oscillations were present at steady-state; fluctuations ranged from 22 to 34%. However, no circadian rhythm was apparent. On the basis of these findings, it appears that the value of a single fasting sample during therapeutic monitoring of valproic acid is questionable. For an accurate evaluation of valproic acid plasma levels, an average concentration based upon several daily determinations should be performed.

Carbamazepine (CBZ) binding by human plasma proteins was studied by means of three different techniques : ultrafiltration, equilibrium dialysis and MSA (Microspheres of Serum Albumin). The validity of the new MSA procedure for determining binding parameters was confirmed. The effects of plasma dilution and of temperature were also investigated. The association constant for albumin was found to be relatively low : 1.35 × 10 3 l/mole with an n value of 1.06 sites/mole. The data suggest that other proteins may be implicated in CBZ binding by human plasma. For concentrations within the therapeutic range (5–30 μg/ml) the unbound fraction of CBZ was 24%.

The behavioural effects of both apomorphine (stereotypies) and haloperidol (catalepsy and reversal of stereotypies) were significantly enhanced in hypophysectomized rats compared with sham-operated rats. Both the efficacy and duration of action were increased. Hypophysectomized animals had significantly greater brain haloperidol concentrations than did sham-operated animals. The data suggest that changes in brain drug concentrations following hypophysectomy at least partially explain the behavioural alterations seen in this test situation.

Summary: Sodium valproate (VPA) was administered for 1 week (1 g b.i.d.) to seven epileptic patients receiving chronic carbamazepine (CBZ) therapy. Steady-state CBZ levels determined before and after VPA therapy were reduced by 3–59% in six patients and were unchanged in one patient. The plasma concentration ratio of carbam-azepine-10, 11-epoxide (CBZE) to CBZ increased in all patients by 11–500%. The plasma binding of CBZ was determined in six healthy volunteers given a single 400 mg CBZ dose with and without the coadministration of 1 g VPA in a cross-over design. The mean CBZ free-fraction was increased in three of the subjects (p = 0.008-0.031), decreased in one subject (p < 0.002), and remained unchanged in two subjects when VPA was administered. Four male rhesus monkeys were infused intravenously with CBZ (15 mg h-1) for 5 days and then three consecutive 24-h infusions were given: I, CBZ alone; II, CBZ with 75 mg h-1 VPA; III, CBZ with 150 mg h-1 VPA. The mean free-fraction of CBZ and CBZE increased during infusions II and III from 31.5 ± 2.7% to 33.2 ± 6.6% (p < 0.05) and 37.7 ± 1.3% (p < 0.01) for CBZ and from 46.9 ± 9.2% to 53.6 ± 5.7% (p ± 0.05) and 60.1 ± 4.0% (p < 0.01) for CBZE. The clearance of free CBZ declined from 7.96 ± 1.75 to 4.84 ± 1.26 (p < 0.01) and 4.12 ± 1.75 (p < 0.01) 1 kg-1 hr-1 during infusions II and III, respectively. The mean free CBZE/CBZ ratio increased from 0.12 ± 0.03 to 0.24 ± 0.03 and 0.36 ± 0.04 during infusions II and III, respectively (p < 0.001). These findings indicate a decrease in the elimination clearance of CBZE possibly coupled with a decrease in its formation clearance. VPA also appears to decrease the binding of CBZ in man and CBZ and CBZE in the monkey. RESUMEN Durante una semana se administro valproato sodico (VPA) a 7 epilepticos (1 g, dos veces diarias) que estaban en tratamiento cronico con carbamazepina (CBZ). Se determinaron los niveles basales de CBZ antes y despues de que el tratamiento con VPA se redujera entre un 3 y 59% en 6 enfermos, y no se cambiase en un paciente. La relation entre les concentraciones plasma-ticas de carbamazepine-10,11-epoxido (CBZE) y las de la aumentaron en un 11 a 500% en todos los enfermos. El acopla-miento plasmatico de la CBZ se determino en 6 voluntaries sanos tras la administration de una dosis unica de CBZ con y sin la co-administracion de 1 g de VPA en un diseno crossover. La media de la fraction libre de CBZ incremento en 3 de los enfermos (p = 0.008-0.031), disminuyo en un caso (p < 0.002) y no se modifico en dos sujetos cuando se administro el VPA. Se inicio una infusion i.v. de CBZ (15 mg h-1) a 4 rhesus machos durante 5 dias y, despues, se inyectaron tres infusiones conse-cutivas durante 24 horas: 1a, solo CBZ; 2a, CBZ con 75 mg h-1 de VPA; 3a, CBZ con 150 mg h-1 de VPA. Los valores medios de las fracciones libres de CBZ y CBZE aumentaron durante les infusiones 2a y 3a de 31.5 ± 2.7% a 33.6 ± 2.6% (p < 0.05 y 37.7 ± 1.3% (p < 0.01) para la CBZ y de 46.9 ± 9.2% a 53.6 ± 5.7% (p ± 0.05) y 60.1 ± 4.0% (p < 0.01) para el CBZE. El aclaramiento de CBZ libre decreci

Human platelets have been shown to possess high-affinity binding sites for 3H-imipramine. These binding sites have a similar affinity and drug specificity to those already described in rat brain. The platelets from healthy volunteers show no difference in 3H-imipramine binding between the sexes but there is a decrease in maximal 3H-imipramine binding with increasing age of the donor.

Fifteen patients affected by Huntington's chorea were divided into two groups, 'slow' and 'fast', according to IQ scores on the Wechsler-Bellevue scale, and scores on some motor performance tests. A possible correlation was looked for between some biochemical data (cerebrospinal fluid (CSF), homovanillic acid (HVA), and 5-hydroxyindolacetic acid (5HIAA) levels, plasma dopamine-beta-hydroxylase (DBH), dopamine (DA) uptake by platelets), and clinical data (duration of illness, severity of symptoms, age of patients, IQ scores, 'slow' and 'fast' groups). The CSF, HVA, and 5HIAA levels were found to be significantly lowered in comparison with normal controls. DBH activity and DA uptake by platelets did not differ significantly from normal subjects. Treatment with haloperidol in all patients and with dipropylacetic acid in three patients did not appear to modify the CSF, HVA, and 5HIAA concentrations, the plasma DBH activity, or the DA uptake. There were no significant differences in the CSF, HVA, and 5HIAA contents between the two groups of patients, and there was no correlation between biochemical data and clinical features.

1. In patients with mild or moderate essential hypertension, oral propranolol, given in incremental doses, produced a moderate but significant lowering of blood pressure which was correlated with the concentration of propranolol in plasma. 2. Propranolol also reduced plasma renin activity (PRA) in the supine posture, on standing and after intravenous frusemide. However, ‘supine’ and ‘frusemide’ PRA values were markedly reduced at a plasma concentration of propranolol that had little effect on blood pressure. 3. On administration of propranolol there was little correlation between blood pressure decrease and PRA suppression, and even less between pretreatment PRA values and hypotensive response. 4. It is concluded that in patients with mild and moderate hypertension and low or normal plasma renin activity, suppression of PRA is not an important determinant of the hypotensive response to propranolol.

1. GABAergic mechanisms have been generally ignored in the study of mood disorders and antidepressant drug (AD) action. Recently data have accumulated indicating that GABAergic mechanisms may be involved in both of these. 2. Mood disorders: GABA levels are reported to be low in the CSF and plasma of depressed patients and are related to mood changes. GABA B receptors are decreased in the frontal cortex in two rodent behavioral models of depression and GABA release is reported diminished in the hippocampus. GABAergic drugs (progabide, fengabine) reverse the behavioral deficits in the rodent models and exert clear therapeutic effects in depressed patients. 3. AD action: In behavioral models imipramine upregulates GABA B receptors only in those animals which respond behaviorally to the AD. In naive rats repeated administration of varied ADs upregulates GABA B receptors in the frontal cortex whereas non-ADs (including amphetamine) do not. Bicuculline inhibits the action of imipramine in the learned helplessness model. GABA A receptor stimulation enhances noradrenaline release in the ventral NA pathway. 4. Conclusions: GABAergic mechanisms likely play a role in the modulation of mood and increasing GABAergic tone exerts an antidepressant effect. Actions at GABA synapses appear to be a fundamental facet of ADs, perhaps together with s-adrenoceptor mediated events.

Following an integrated approach based on the contemporary recording of drug plasma levels, central (CNS) and peripheral responses and performance tests, the effects of two different amphetamine formulations were evaluated in healthy volunteers. Interesting relationships were observed between amphetamine initial rate of entry into the blood stream and both incidence of side effects (S.E.) and rise in arterial blood pressure. Minimal thresholds for CNS (5 ng/ml) and peripheral (20 ng/ml) effects could also be determined. It appeared also that the personality of the subject may have some bearing on both incidence of side effects and performance. The described methodology seems valuable in valuating psychotropic drug effects in man through a comprehensive integrated approach.

The binding of alpidem, a new anxiolytic drug, has been studied in plasma from 6 healthy subjects, 12 patients with renal failure, 12 patients with liver cirrhosis and 12 chronic uraemics maintained on haemodialysis, as well as in 12 serum samples from the placental cord, to represent the situation in the newborn. The unbound fraction was 0.61% (healthy volunteers), 1.31% (newborns), 0.86% (cirrhotic patients), 0.72 (patients with renal failure), 0.70% (before haemodialysis) and 0.79% (after haemodialysis). Binding in the volunteers was significantly different from that in neonates and cirrhotics only. Alpidem became bound to isolated albumin (45 g.l-1) and alpha 1-acid glycoprotein (0.75 g.l-1) to 97.2% and 97.1%, respectively. The bound fraction of the drug in a mixture of two proteins was 99.1%. For alpidem, it appears that alpha 1-acid glycoprotein may balance the effect of any decrease in the albumin concentration.

Amantadine, administered at a dose of 200 mg/day, antagonized the extapyramidal symptomatology induced by neuroleptic drugs in fifteen psychiatric patients. Steady-state levels were reached within 4-7 days of treatment. Individual plasma levels ranged from 200-900 ng/ml. Apparent plasma half-lives varied from 10-28.5 h with an apparent VD of 200-400 litres. A significant relationship was found between the plasma levels of amantadine and the effects on the extrapyramidal symptomatology. The data suggest a direct effect of amantadine on dopaminergic receptors.

The influence of progabide, a new antiepileptic drug, on the pharmacokinetic profiles of phenobarbital, phenytoin, carbamazepine, and valproic acid was evaluated in four separate studies, each including six young healthy volunteers. The pharmacokinetic parameters of the associated antiepileptic drugs were measured before and after repeated administration of progabide (600 mg t.i.d.) for 15 days. A significant reduction of the total body clearance of both phenytoin and phenobarbital and a higher Cmax value of carbamazepine epoxide and phenobarbital were observed. No modifications were noticed for the kinetic profiles of carbamazepine and valproic acid. These modifications may be of clinical relevance and suggest that, as a general rule, when progabide is added to an established treatment with phenobarbital or phenytoin or carbamazepine, an adjustment of previous posology may be necessary.