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Biomedical subjects

C F George

Publications and source records attributed to C F George.

At least 127 records · Page 7Linked to original sources
PubMed1982

The electrocardiographic and anticholinergic effects of trazodone and imipramine in man.

The electrocardiographic and anticholinergic effects of trazodone (150 mg) and imipramine (75 mg) were investigated in 8 healthy volunteers. Both agents increased the QTc interval and decreased T wave height, but the effects occurred earlier with trazodone (from 30 min onwards) than with imipramine (150 and 180 min after dosing). Both drugs decreased heart rate, imipramine at 30 and 60 min and trazodone at 90 min. After 120 min, heart rate began to increase with imipramine an effect which was not seen with trazodone. Salivary volume was significantly decreased by imipramine at 120 and 180 min whereas trazodone did not influence salivary volume. Plasma levels of trazodone and imipramine were significantly related to the decrease in T wave amplitude. The increase in QTc interval correlated significantly with the plasma level of imipramine. These results suggest that trazodone, like the tricyclic antidepressants prolongs ventricular repolarization; but, in contrast to imipramine, it does not have anticholinergic activity.

Adult↗
PubMed1982

Hemodynamic responses of trazodone and imipramine.

The hemodynamic effects of trazodone (150 mg) and imipramine (75 mg) were examined in eight healthy subjects. Trazodone significantly increased left ventricular ejection time 1 (LVETI), but decreased both preejection period (PEP) and PEP/LVET ratio. It also decreased heart rate and systolic and diastolic blood pressure at 90 min after dosing. Imipramine initially increased total electromechanical systole I (QS2I) and PEP (30 min, P less than 0.01), but at 150 and 180 min after dosing QS2I was significantly lower. Imipramine increased diastolic blood pressure at 30 min (P less than 0.05) and increased systolic blood pressure between 90 and 180 min (P less than 0.05). At 30 and 60 min heart rate was significantly depressed by imipramine. There were no significant changes in the values of stroke volume and cardiac output. These results suggest that trazodone has its major effect on the circulation through its alpha-receptor blocking activity, whereas the effects of imipramine are probably mediated through its ability to block reuptake of norepinephrine.

Adult↗
PubMed1981

Imipramine--a possible alternative to current therapy for urinary incontinence in the elderly.

Imipramine was given orally at night to 10 elderly patients with urinary incontinence associated with spontaneous unstable detrusor contractions. The dose was increased for each patient up to a maximum of 150 mg. at night, or until continence was achieved or side effects occurred. Of the 10 patients 6 became continent. In 3 of the 6 patients who underwent repeat cystometry bladder capacity had increased (mean 105 cc), bladder pressure at capacity decreased (mean 18 cm. water) and urethral pressure increased (mean 30 cm. water). There was no correlation between plasma desmethylimipramine and dose, or clinical or urodynamic effect.

Aged↗
PubMed1979

The rationale of treating high blood pressure in the elderly.

The elderly are at risk from stroke and cardiac complications of hypertension. There is strong circumstantial evidence to indicate that these risks may be reduced by hypotensive therapy. However, the decision to treat must be taken after careful appraisal of the patient and, because the risks of therapy are higher in this age group, the choice of drugs should be restricted.

Adrenergic beta-Antagonists↗
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↗