Journal of Antimicrobial Chemotherapy (1986) 18, 213-219
© 1986 The British Society for Antimicrobial Chemotherapy
research-article |
Metronidazole metabolism following oral benzoylmetronidazole suspension in children with giardiasis
a Department of Medicine, Faculty of Medicine University of Khartoum P.O. Box 102, Khartoum, Sudan b University Department of Medicine, Bristol Royal Infirmary Bristol BS2 8HW, England c Department of Pharmacology, Faculty of Pharmacy, University of Khartoum P.O. Box 1996, Khartoum, Sudan d Clinical Assay Unit, May and Baker Limited Dagenham, Essex RM10 7XS, England
accepted 3 February 1986
Correspondence and rerint requests to Dr T. K. Daneshmend, Department of Therapeutics, Floor C, South Block, University Hospital, Nottingham NG7 2UH, England.
A suspension of benzoylmetronidazole (6.4% w/v) was given orally at a dose of 15–25 ml, equivalent to 0.6-1 g metronidazole, once a day for three days to 11 children with giardiasis. Blood samples were collected after the first and third doses for analysis of plasma metronidazole and its main oxidative metabolite by high performance liquid chromatography. Peak metronidazole concentrations were 22.60±8.52 mg/l (mean±S.D.) after the first dose, and 30.22±10.06 mg/1 after the third dose, occurring at 3.6±1.4 and 4.4±2.9 hours post-dose, respectively. Peak concentrations of the metabolite were 4.26±1.94 mg/l after the first dose and 7.96±3.63 mg/1 after the third dose, occurring 7.2±1.6 and 9.1±3.3 h post-dose, respectively. Calculation of plasma metronidazole half-life and clearance values was not possible.
This study shows that oral administration of metronidazole as its benzoyl ester slows the rate of metronidazole absorption, followed by sustained plasma concentrations and a prolonged elimination phase. Giardiasis does not appear to prevent metronidazole absorption. Concurrent giardiasis is unlikely to influence metronidazole therapy for systemic anaerobic infections.