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Biomedical subjects

C M Castleden

Publications and source records attributed to C M Castleden.

At least 109 records · Page 6Linked to original sources
PubMed1980

The effect of flavoxate on uninhibited detrusor contractions and urinary incontinence in the elderly.

The effect of flavoxate, a smooth muscle relaxant, was investigated in 6 elderly patients with uninhibited detrusor contractions associated with urinary incontinence. Cystometry was done initially to confirm the diagnosis, immediately after an intravenous injection of 100 mg. flavoxate and after 200 mg. flavoxate orally 4 times daily for 7 days. No consistent drug effect could be detected cystometrically and incontinence was unchanged clinically.

Aged↗
PubMed1979

The effect of ageing on the hepatic clearance of propranolol.

1. Plasma propranolol concentrations were measured in healthy old and young subjects following single oral doses of 40 mg, single i.v. infusions of 0.15 mg kg-1 and after nine 40 mg oral doses given four times daily. 2. In each of the three studies, the elderly had higher plasma propranolol concentrations than the young despite having similar apparent volumes of distribution. 3. The terminal half-life of propranolol was similar in the two groups after oral propranolol but significantly shorter in the young after intravenous dosing (P less than 0.05). 4. The bioavailability assessed from the concentration-time curves after i.v. and oral dosing was greater in the elderly (P less than 0.05). 5. The differences between peak concentrations observed in old and young subjects after single oral doses were maintained during chronic therapy and there was a correlation between the individual values obtained on multiple therapy with that after a single dose (P less than 0.05). 6. Ageing appears to affect the pharmacokinetics of propranolol in two ways. Firstly, distribution to the tissues appears to be slowed. Secondly, the increased bioavailability following oral administration suggests diminished intrinsic clearance by metabolism.

Administration, Oral↗
PubMed1979

Chlormethiazole--no hangover effect but not an ideal hypnotic for the young.

The hangover effects of 768 mg chlormethiazole, an hypnotic with a half-life of approximately 4 hr, were compared with those of placebo in a double-blind cross-over study in 8 young subjects. Ten hours after dosing there were no differences between the preparations in the subjects' psychomotor performance, EEG sleep scores, or visual analogue ratings. Thus, an hypnotic which is rapidly removed from the body may confer considerable advantages. However, all 8 subjects had unpleasant nasal symptoms following chlormethiazole, and it is therefore not an ideal hypnotic for this age group.

Adult↗
PubMed1978

Contribution of individual differences in gastric emptying to variability in plasma propranolol concentrations.

1 No correlation was found between the rate of gastric emptying and peak plasma propranolol concentrations in six hypertensive patients after single oral doses of 80 mg. 2 In four normal subjects given oral propranolol the peak plasma concentration was highest when a simultaneous injection of metoclopramide and lowest when propantheline was given. The mean time to peak was 1.5 h after metoclopramide, 2.8 h after normal saline and 4.5 h after propantheline. 3 Gastric emptying has some influence on the time of peak plasma propranolol concentrations but individual variation in its bioavailability is determined mainly by first-pass metabolism in the liver.

Administration, Oral↗
PubMed1977

A second look at emepronium bromide in urinary incontinence.

Response to oral and intramuscular emepronium bromide was assessed cystometrically in nine patients with urinary incontinence caused by an uninhibited bladder. Oral therapy had no effect, whereas intramuscular administration increased bladder capacity and significantly delayed the onset of bladder spasm and the desire to void. Plasma-propranolol response was delayed and concentrations were reduced after an oral 40 mg dose of propranolol in 3 patients who had received oral emepronium bromide. These results indicate that although oral emepronium bromide had some anticholinergic effect--i.e., in reducing gastrointestinal motility--absorption of an oral dose was not sufficient for the bladder to be affected.

Administration, Oral↗
PubMed1977

Increased sensitivity to nitrazepam in old age.

The effects of a single 10 mg oral dose of nitrazepam were compared with those of a placebo in healthy young and old people. Both the young and the elderly slept better on three successive nights after nitrazepam but they felt less awake at 12 and 36 hours (P less than 0-01). Elderly people made significantly more mistakes in a psychomotor test than did the young, despite similar plasma concentrations of nitrazepam and half lives in the two groups. This difference in response to psychomotor testing is probably explained by an increased sensitivity of the ageing brain to the action of nitrazepam.

Adult↗
PubMed1977

The effect of ageing on drug absorption from the gut.

Single oral doses of aspirin and practolol were given to young and old subjects. The results of the plasma concentration-time curves were subjected to pharmacokinetic appraisal. There was no difference with either drug between the two age-groups in the mean absorption rate constant and the time at which maximum concentration in the plasma occurred. However, the amount of drug in the plasma of the elderly group was the same or higher than that in the younger group. It is concluded that ageing has no significant effect on the rate or amount of these drugs absorbed.

Administration, Oral↗
PubMed1977

A comparison of once and twice daily atenolol in hypertension.

The hypertensive action of atenolol has been studied in a randomized double-blind crossover comparison. Twelve patients showed a highly significant reduction in average supine systolic and diastolic blood pressures from pre-treatment values of 196.3/115.9 to 159.1/89.2 mmHg (26.1/15.4 kPa to 22.2/11.9 kPa) after 2 weeks on once daily atenolol. No dose-related reduction in blood pressure was seen and the single 100 mg daily dose was as effective as 100 mg twice daily or 50 mg twice daily. Blood pressures recorded after 2 weeks' atenolol were lower than those obtained at 7 days irrespective of dose.

Adult↗
PubMed1977

Who is responsible for elderly patients on orthopedic wards?

A retrospective survey of the geriatrician's role on the orthopedic ward showed that his or her main aim should be to advise the orthopedic team of the advantages of long-term planning for every elderly patient admitted. From the moment of the initial assessment, it is important to emphasize the need for a more detailed medical, social, and psychiatric history; to alter the management of incontinence; and to point out the differences in the nursing and rehabilitation requirements of elderly patients. Once this is achieved, the geriatrician should revert to the role of the clinical adviser in medical diseases affecting the elderly.

Aged↗
PubMed1975

The effect of age on plasma levels of propranolol and practolol in man.

1. Plasma levels of propranolol and practolol were measured in groups of elderly and young subjects, after the oral administration of propranolol (40 mg) and practolol (200 mg) on separate occasions. 2. At all sampling times the mean plasma propranolol level in the group of elderly subjects was substantially greater than the corresponding level in the group of young subjects, there being a significant difference between the two, and a fourfold difference in the mean peak levels. 3. After practolol, there was no significant difference between the mean plasma concentrations of the drug in the two groups for the first 2 hours. Subsequently, the mean plasma levels in the group of elderly subjects were somewhat higher than the corresponding levels in the young group, the differences between the two reaching significance. 4. It is suggested that there is a need to substantially reduce the dose of propranolol given to elderly patients. With practolol, however, no reduction is necessary providing renal function is normal for the patient's age.

Administration, Oral↗
PubMed1975

Carboxyhaemoglobin levels of smokers and non-smokers working in the City of London.

The carboxyhaemoglobin (COHb) levels of two groups of workers in the City of London were determined. The mean COHb in smokers (5-8%) was significantly greater than that of the non-smoking group (1-3%). In general, cigarette consumption could be directly related to the COHb level but there was considerable individual variation. The mean COHb level of manual workers was significantly lower than that of sedentary workers even though the former group tended to smoke more heavily.

Blood Donors↗
PubMed1974

Variations in carboxyhaemoglobin levels in smokers.

Three experiments on smokers have been performed to determine variations in blood levels of carboxyhaemoglobin (COHb) throughout the day and night and whether a random measurement of COHb gives a true estimation of a smoker's mean COHb level. In the individual smoker the COHb level does not increase gradually during the day but is kept within relatively narrow limits. Moderately heavy smokers rise in the morning with a substantially raised COHb level because the half life of COHb is significantly longer during sleep than during the day. Women excrete their carbon monoxide faster than men. A random COHb estimation gives a good indication of the mean COHb level of an individual.

Carboxyhemoglobin↗