Gillian M. Paddock

Cephradine Bone Concentrations During Total Hip Replacement

We have previously reported the concentrations of lincomycin achieved in aseptic hone (1.2) after an empirical parenteral prophylactic regime of this antibiotic given during total hip replacement (THR).

Antibiotic Absorption in Crohn’s Disease

Previous studies “by our group (1–4) have demonstrated statistically significant differences in the mean ± SEM plasma concentration & urinary excretion of a number of antibiotics in adult patients with coeliac disease & small bowel diverticulosis. Since the upper small intestine is considered to be an important site of drug absorption (5), we wondered whether abnormalities of the lower jejunum & ileum, such as Crohn’s disease (regional ileitis) might also affect antibiotic absorption.

Lincomycin Bone Concentrations During Total Hip Replacement

Empirical antibiotic regimes given during total hip replacement (THR) are now widely used by most orthopaedic units to reduce the incidence of postoperative infections. In an elderly patient who has already under gone one operation, an infection is a therapeutic disaster since it requires a second operation to remove the prosthesis in a patient who is already debilitated, and therefore at risk. Thus, it is of the utmost importance that the antibiotics used are shown to provide adequate concentrations in bone.

Cholestyramine Induced Antibiotic Malabsorption

Cholestyramine is a basic anion exchange resin which is increasingly being used in the treatment of hyperlipidaemia. Its main pharmacological action is to chelate with bile acids, preventing their normal enterohepatic recycling by the formation of an insoluble bile acid-resin complex. This bypasses the terminal ileum, the normal site for active reabsorption of bile acids back into the portal circulation, from which they re-enter the liver.

EFFECT OF RECUMBENCY ON ERYTHROMYCIN ABSORPTION

During a concurrent bioavailability study of pivmecillinam, the results of which have been reported elsewhere in the proceedings of this Congress (1) we obtained significantly different mean plasma concentrations of mecillinam compared with those found by another centre investigating this compound. One possible cause for this difference is that supine subjects were studied by the other group, whilst we had studied subjects performing their normal working activities. This finding prompted us to undertake the present study. This was designed to ascertain whether the activity of the subject affected the absorption of erythromycin.

Plasma Profile & Urinary Excretion of Mecillinam after Pivmecillinam

Pivmecillinam (F.L. 1039. Leo) is the pivaloyloxymethyl ester of mecillinam (F.L. 1060. Leo). Like the related pivampicillin, which is the pivaloyloxy methyl ester of ampicillin, pivmecillinam is biologically inactive Until in-vivo hydrolysis to its biologically active constituent mecillinam. These reactions are shown in Fig. 1.