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Biomedical subjects

L F Prescott

Publications and source records attributed to L F Prescott.

At least 163 records · Page 9Linked to original sources
PubMed1973

Pharmacological modification of gastric emptying: effects of propantheline and metoclopromide on paracetamol absorption.

The rate of paracetamol absorption depends on the rate of gastric emptying. Propantheline delayed gastric emptying and markedly slowed the absorption of paracetamol in six convalescent hospital patients. Conversely, the absorption of paracetamol in five healthy volunteers was accelerated by metoclopramide, a drug which stimulates gastric emptying. The total 24-hour urinary excretion of paracetamol was not influenced by propantheline or metoclopramide. Other similar absorption interactions probably occur since drugs are poorly absorbed from the stomach and many therapeutic agents influence gastrointestinal motility.

Acetaminophen↗
PubMed1973

The dependence of paracetamol absorption on the rate of gastric emptying.

1. The rate of gastric emptying was measured directly in 14 convalescent hospital patients and paracetamol absorption was studied following an oral dose of 1.5 g.2. Rapid gastric emptying was associated with the early appearance of high peak plasma paracetamol concentrations whereas peak concentrations were low and occurred late when gastric emptying was slow.3. There was a significant correlation between the rate of gastric emptying and the 0-4 and 0-24 h urinary excretion of paracetamol and its metabolites.4. In five patients with abnormally slow gastric emptying the mean maximum plasma concentration and 0-4 and 0-24 h urinary excretion of paracetamol were significantly lower than in seven patients with normal gastric emptying rates while the time taken to reach maximum plasma concentrations was longer.5. Individual differences in the rate of gastric emptying may contribute to variable absorption of many drugs.

Acetaminophen↗
PubMed1973

The effects of hepatic and renal damage on paracetamol metabolism and excretion following overdosage. A pharmacokinetic study.

1. The kinetics of paracetamol metabolism and excretion were studied in 41 patients following overdosage. Acute hepatic necrosis developed in 23 patients and in 3 of these acute renal failure also occurred. Two patients died in hepatic failure.2. Paracetamol metabolism was impaired in the patients with liver damage. The plasma half-life of the unchanged drug was significantly prolonged, and the ratio of the plasma concentrations of unchanged to conjugated paracetamol was significantly higher than in the patients without liver damage.3. Paracetamol and its conjugates were rapidly excreted in the urine. However, excretion was slower in patients with liver damage and a higher proportion was excreted unchanged.4. The renal clearance of unchanged (but not conjugated) paracetamol was related to the urine flow rate. However, forced diuresis is of no practical value and is contraindicated on clinical grounds. There was no correlation between urine pH and clearance of unchanged or conjugated drug.5. In patients with hepatic necrosis there was a marked decrease in the overall elimination rate constant which could be accounted for by decreased metabolite formation. Except in patients with acute renal failure, the urinary excretion rate constants were similar to those observed in patients without liver damage.

Acetaminophen↗