Pharmacokinetics of amoxycillin in elderly in-patients
The pharmacokinetics of amoxycillin (500 mg) given by intravenous injection and as two oral formulations on three consecutive days were investigated in eight frail elderly in-patients. Marked interindividual variation was found in all kinetic parameters after intravenous injection. The area under the curve (AUC) ranged from 32 to 155 mg·l−1·h and the distribution volume ranged from 13 to 37 1. The mean plasma clearance was 109 ml/min (range 53 to 255 ml/min). Elimination half-life ranged from 1.6 to 3.0 h (mean 2.4 h). The absolute bioavailability after oral administration was highly variable and ranged from 24 to 86% (mean 55%). The bioavailability of the two formulations was not significantly different. The performance of a pharmacokinetic study in these patients was very difficult, regarding their inability to tolerate an intravenous infusion, incontinence, disruption of everyday routine and problems with drinking the required volume of water.
KeywordsAmoxycillin Biological availability Capsules Frail elderly Injections, intravenous Pharmacokinetics Tablets
Unable to display preview. Download preview PDF.
- 1.Sjövall J, Alvan G, Huitveldt B. Intra- and interindividual variation in pharmacokinetics of intravenously infused amoxycillin and ampicillin to elderly volunteers. Br J Clin Pharmacol 1986;21:171–81.Google Scholar
- 2.Cockroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16:31–41.Google Scholar
- 3.Krauwinkel WJJ, Volkers-Kamermans NJ. Determination of amoxycillin in human plasma by means of HPLC and solid phase clean up. J Chromatogr. In press.Google Scholar
- 4.Brogden RN, Heel RC, Speighr TM, Avery GS. Amoxycillin injectable. A review of its antibacterial spectrum, pharmacokinetics and therapeutic use. Drugs 1979;18:169–84.Google Scholar
- 5.Cortvriendt WR, Verschoor JS, Hespe W. Bioavailability study of a new amoxycillin tablet designed for several modes of oral administration. Arzneimittelforschung 1987;37:977–9.Google Scholar