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Biomedical subjects

A N Nicholson

Publications and source records attributed to A N Nicholson.

At least 19 recordsLinked to original sources
PubMed1979

L-tryptophan and sleep in healthy man.

The effect of L-tryptophan on night-time and day-time sleep (from 14.00 h) sleep was studied in six healthy males aged between 20 and 30 years. The doses used in the night-time studies were 2, 4 and 6 g, and in the day-time studies 1, 2 and 4 g. It was not possible to establish an effect of L-tryptophan compared with placebo on night-time sleep, but analysis of the sleep measures with 4 g compared with placebo and the other doses of L-tryptophan considered together suggested reduced awakenings, increased stage 3 and an increased percentage of REM sleep. With 4 g L-tryptophan there was an increase in the duration of stage 3 of day-time sleep compared with placebo. The studies provide marginal evidence that REM sleep may be modified by L-tryptophan in man, though the evidence is somewhat stronger that SWS may be increased. The effect on REM sleep may involve circadian mechanisms. The hypnotic activity of L-tryptophan per se is limited and uncertain.

Adult↗
PubMed1979

Performance studies with diazepam and its hydroxylated metabolites.

1 Visuo-motor coordination has been used to study the immediate and residual effects of benzodiazepines on performance in man. The technique provides dose and time response data related to the decrement and the persistence of impaired performance. 2 With the overnight ingestion of flurazepam hydrochloride 30 mg and nitrazepam 10 mg, performance was impaired to 16 h and, at least, 19 h, respectively. Performance was not impaired after the overnight ingestion of diazepam, 5 and 10 mg, temazepam 10, 20 and 30 mg or oxazepam 15 and 30 mg. However, with temazepam 30 mg there was a trend toward impaired performance,, and with oxazepam 45 mg, performance was impaired 10 h after ingestion. With morning ingestion, coordination was impaired 0.5 and 2.5 h after diazepam 10 mg, at 0.5 h after temazepam 20 mg, and after oxazepam 30 mg at 2.5 and 4.5 hours. 3 The studies suggest that diazepam 5-10 mg, temazepam 10-20 mg and oxazepam 15-30 mg may be of use in the management of sleep disturbance when impaired performance the next day is to be avoided.

Barbiturates↗
PubMed1979

Differential effects of the 1,4 and 1,5 benzodiazepines on performance in healthy man.

1 The immediate and residual effects on performance of benzodiazepines differ, and the differences are important in the use of these drugs. 2. Diazepam and its hydroxylated metabolites, temazepam and oxazepam, each possess hypnotic activity, and have effects on performance limited to the sleep period. The demethylated metabolite of diazepam, nordiazepam, and its precursor, potassium clorazepate, which also possess hypnotic activity, have a longer duration of action, although the next day anxiolytic effect is accompanied by only minimal effects on performance. The 1.5 benzodiazepine, clobazam, seems to have minimal immediate effects on performance. 3 Diazepam and its hydroxylated metabolites, temazepam and oxazepam, would be useful in the management of insomnia without psychopathology in those cases in which residual effects on performance must be avoided. Nordiazepam and potassium clorazepate would be appropriate for insomnia secondary to day-time anxiety, and clobazam may be useful as a day-time anxiolytic. 4 It is emphasized that more work needs to be carried out on the effects of anxiolytics on performance before one can be certain that ingestion during the day would be without any deleterious effects on skilled work.

Anti-Anxiety Agents↗
PubMed1979

Effect of the antihistamines, brompheniramine maleate and triprolidine hydrochloride, on performance in man.

1 Effects of brompheniramine maleate (4 and 12 mg) and triprolidine hydrochloride (2.5 and 10 mg) on visuo-motor coordination, and on subjective assessments of performance, well-being and sleep were each studied in six subjects at 0.5, 1.5, 3.0, 5.0 and 7.0 h after ingestion. The doses refer to immediate and sustained release preparations respectively. 2. Triprolidine hydrochloride (2.5 mg) had an immediate effect on performance which persisted to 3.0 h, and the sustained release preparation (10 mg) impaired performance from 1.5 to 5.0 h. Brompheniramine maleate (4 mg) impaired performance from 1.5 to 3.0 h, and the sustained release preparation (12 mg) impaired performance at 1.5 h. There were no consistent changes in the subjective assessments of performance, or of well-being and sleep. 3. The studies emphasize the variable effects of antihistamines on performance, and suggest that effects on performance of sustained release preparations may be similar to those of the usual form. Sustained release preparations may provide an advantage in clinical practice if the antihistaminic activity is prolonged.

Adult↗
PubMed1979

Hypnotics today.

Explore the source record for details and available documents.

Aged↗
PubMed1978

Performance studies with antihistamines.

1 Effect of four antihistamines, chlorpheniramine (4 mg), clemastine (1 mg), promethazine (10 mg) and terfenadine (60 mg), on visuo-motor coordination and on subjective assessments of performance and well-being were compared with placebo in six healthy females from 0.5--7.0 h after morning ingestion of each drug. The study was double-blind, and the doses used were believed to be equally potent in their antihistaminic activity. 2 There was impaired performance 1.5 h (P less than 0.01) after chlorpheniramine, 3.0 h (P less than 0.05) and 5.0 h (P less than 0.01) after clemastine, and 3.0 h (P less than 0.01) and 5.0 h (P less than 0.001) after promethazine. It was not possible to establish effects on performance after ingestion of terfenadine. Subjective assessments of performance were not altered. 3 The subjects as a group reported improved alertness (P less than 0.05) and improved wakefulness (P less than 0.05) 0.5 h and 3.5 h respectively after ingestion of terfenadine, and were less energetic (P less than 0.05) 7.0 h after ingestion of chlorpheniramine. There were not other consistent changes in assessments of well-being.

Adult↗