Clinical pharmacokinetics of teicoplanin

Abstract

The glycopeptide antibacterial teicoplanin has become increasingly popular in the last decade with the rise in infections related to methicillin-resistant Staphylococcus aureus. Teicoplanin has 6 major and 4 minor components. It is predominantly (90%) bound to plasma proteins. Of the several methods available to measure concentrations in serum, fluorescence polarisation immunoassay has high reliability and specificity. Teicoplanin is not absorbed orally, but intravenous and intramuscular administration are well tolerated. Teicoplanin is eliminated predominantly by the kidneys and only 2 to 3% of an intravenously administered dose is metabolised. Total clearance is 11 ml/h/kg. Steady state is reached only slowly, 93% after 14 days of repeated administration. Elimination is triexponential, with half-lives of 0.4 to 1.0, 9.7 to 15.4 and 83 to 168 hours. Volumes of distribution are 0.07 to 0.11 (initial phase), 1.3 to 1.5 (distribution phase) and 0.9 to 1.6 (steady state) L/kg. A standard dosage regimen of 6 mg/kg every 12 hours for 3 doses, then daily, will produce therapeutic serum concentrations of > or = 10 mg/L in most patients. Higher dosages may be required in certain patients, for example intravenous drug abusers or those with burns, because of unpredictable clearance. Concentrations in bone reach 7 mg/L at 12 hours after a dose of teicoplanin 6 mg/kg, but reach only 3.5 mg/L in the cartilage. Doses of 10 mg/kg are necessary to achieve adequate bone concentrations. There is little penetration into cerebrospinal fluid or the aqueous or vitreous humour. In fat, concentrations may be subtherapeutic (0.5 to 5 mg/L) after a dose of 400mg. A single prophylactic dose of 12 mg/kg is sufficient to maintain therapeutic concentrations during cardiopulmonary bypass or burns surgery. High loading doses reduce the delay to attaining therapeutic concentrations. Premature neonates require a loading dose of 15 mg/kg and a maintenance dosage of 8 mg/kg daily to ensure therapeutic serum concentrations. Children need loading with 10 mg/kg every 12 hours for 3 doses followed by maintenance with 10 mg/kg/day. Clearance is reduced predictably in renal failure, and dosage adjustments can be based on the ratio of impaired clearance to normal clearance. In patients on haemodialysis, 3 loading doses of 6 mg/kg at 12-hour intervals followed by maintenance doses every 72 hours produced trough plasma concentrations of 8 mg/L in most patients at 48 hours. The monitoring of serum concentrations is not necessary to avoid toxicity, but can be helpful in certain patient groups to ensure therapeutic concentrations are present, especially in those not responding to treatment.