We conclude that analgesia at home is often inadequate after painful day-case surgical procedures if single-shot local anaesthetic blockade is used.

Newcastle upon Tyne, NE1 7RUThe pharmacokinetics of metoclopramide have been studied in nine children receiving the drug as prophylaxis for cytotoxic induced vomiting. Plasma concentrations of metoclopramide have also been studied in three children with dystonic reactions to the drug. The pharmacokinetics in children were similar to those reported in healthy adults. There was no difference in the plasma concentration of metoclopramide of children with dystonia when compared to those without this adverse effect. Kinetic differences in childhood do not explain the occurrence of dystonia, which in the individual appears to be related to factors other than plasma drug concentrations.

The plasma, in addition to the liver, is a major site of hydrolysis of aspirin. Human plasma and liver aspirin esterase activities in samples from a group of patients varied over a two fold range and there was a significant correlation between individual plasma and liver activities. Human liver aspirin esterase was present in the cytosolic and microsomal fractions. Cytosolic and microsomal enzymes had different activities and apparent affinities for aspirin.

The efficacy of single doses (1.2 g) of soluble aspirin and aspirin tablets was determined in a randomised, placebo-controlled, double-blind, parallel study in 90 patients (45 females) with postoperative pain after removal of impacted lower third molars. Also investigated was the relationship between plasma aspirin esterase activity and overall pain scores after both aspirin preparations. Patients reported significantly less pain (p less than 0.001) after treatment with aspirin than after treatment with placebo. However, patients receiving soluble aspirin reported both an earlier onset and a longer duration of pain relief than those who received aspirin tablets. A significant correlation was observed between plasma aspirin esterase activity and overall pain scores after both soluble aspirin (r = 0.57, p less than 0.01) and aspirin tablets (r = 0.51, p less than 0.02). It is concluded that soluble aspirin is the preferred aspirin formulation for treating postoperative pain after third molar surgery and that plasma aspirin esterase activity is determinant of a patient's analgesic response to aspirin in postoperative dental pain.

AimsWe hypothesised that pharmacokinetic factors might go some way to explaining the risk of major gastrointestinal haemorrhage with non-steroidal antiinflammatory drugs (NSAIDs), with bleeders exhibiting a reduced clearance of NSAIDs compared with non-bleeders and set out to investigate this. Methods Fifty patients presenting to hospital with acute gastrointestinal bleeding while taking piroxicam, indomethacin, diclofenac or naproxen and age, sex, musculoskeletal disease and drug matched community dwelling controls, up to two for each index case, who had not bled were recruited. Clinical details including duration of therapy were recorded. Bleeders discontinued the implicated NSAID at presentation, controls at least five half-lives before the study. Bleeders were contacted by letter 1 month after discharge and invited to take part and were studied after a median delay of 5 months. Subjects received an oral dose of their respective NSAID and venous blood was sampled, over a period determined by the half-life of the NSAID. Plasma concentrations were determined by high performance liquid chromatography. Results The median length of treatment for the index patients was 1 year (range 2 weeks-28 years) and for the control patients 2 years (1 month-25 years), P<0.0005. There were no significant differences in peak plasma concentration, time to peak plasma concentration or area under the plasma concentration-time curve between bleeders or controls for any of the NSAIDs studied, apart from piroxicam C max being lower in bleeders at 2.07 mg l −1 than in controls at 3.21 mg l −1, mean difference (95% CI) −1.14 (−1.83-−0.48), P<0.005. Conclusions The data failed to support the hypothesis that reduced clearance of NSAIDs, which results in higher plasma concentrations, is a risk factor for acute gastrointestinal haemorrhage.