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Biomedical subjects

T R Shaw

Publications and source records attributed to T R Shaw.

At least 73 records · Page 4Linked to original sources

Cardiac and respiratory standstill during sleep.

An obese man, with an attack of myocardial ischaemia, developed arrhythmias only when he was asleep. Episodes of sinus bradycardia occurred progressing to arterioventricular block and sinus arrest. These changes in the cardiac rhythm coincided with periods of sleep apnoea.

Apnea↗

Observations in man of hypoglycaemia during selective and non-selective beta-blockade.

The acute hypoglycaemic reaction is accompanied by a rise in systolic and a slight fall in diastolic blood pressure and a tachycardia. In contrast, during beta-blockade with propranolol there is a rise of both systolic and diastolic blood pressures and bradycardia. Restoration of blood glucose to normal is delayed. With metoprolol there is a lesser increase in diastolic blood pressure and a slight tachycardia. Restoration of the blood glucose to normal is little delayed. When patients liable to hypoglycaemia require a beta-blocking agent, it is suggested that a selective blocker such as metoprolol should be used.

Acute Disease↗

Procainamide absorption studies to test the feasibility of using a sustained-release preparation.

Using in vitro techniques it was confirmed that whilst the release of procainamide from the conventional formulation (Pronestyl) was rapid, that from the sustained-release preparation (Cardiorytmin Retard) occurred over a prolonged period. 2 The peak plasma procainamide concentrations after single doses of Cardiorytmin Retard were relatively lower and occurred later than those after single doses of Pronestyl. Furthermore, after reaching a peak, the fall in plasma procainamide concentration was less rapid after the sustained-release preparation. Early urinary recovery of procainamide in patients and in healthy volunteers was greater after Pronestyl than after Cardiorytmin Retard, though overall recovery in urine was similar. These findings indicate that the absorption of the sustained-release preparation is slower, though the overall bioavailabilities of the two preparations are almost the same. 3 These results confirm the feasibility of using a sustained-release procainamide preparation, such as Cardiorytmin Retard, since it would be possible to administer the same amount of drug in fewer daily doses without plasma concentrations becoming ineffective towards the end of each dosing interval.

Adult↗

Therapeutic non-equivalence of digoxin tablets in the United Kingdom: correlation with tablet dissolution rate.

Seven types of digoxin 0.25 mg tablet in common use in the United Kingdom were administered to a total of 38 patients. Significant differences were found in the mean plasma digoxin levels and in the control of atrial fibrillation achieved with these brands. There was a close correlation between the dissolution rate of the tablets and the plasma digoxin levels. Measurement of in-vitro dissolution rate appears to be a valid method of ensuring that different tablets of digoxin are of equal efficacy. However, in some patients absorption of the drug is markedly sensitive to changes in dissolution rate and new pharmacopoeal standards should not be defined until very rapidly-dissolving formulations have been studied.

Administration, Oral↗