A lipoglycopeptide antibiotic ---Teicoplanin

DESCRIPTION 

Teicoplanin (Targocids) is a lipoglycopeptide antibiotic chemically related to vancomycin, which was obtained by fermenting Actinoplanes teichomyceticus. Similar to vancomycin, it has a broad spectrum of activity against Gram-positive aerobic and anaerobic bacteria, including strains resistant to many other antimicrobials. Teicoplanin comprises six closely related major components whose activities against specific microbial species differ. Its empirical formula is C89H108N9O35Cl2 and its molecular mass is 1993. 

Teicoplanin binds to the cell wall and inhibits cell wall biosynthesis in susceptible organisms by interfering with the polymerization of peptidoglycan. Like all (lipo)glycopeptides, it is not active against Gram-negative bacteria because it cannot cross their cell wall. Teicoplanin is licensed for parenteral use only.

MECHANISM OF DRUG ACTION 

The mode of action of teicoplanin on bacterial cell walls is similar to that of vancomycin , but the additional actions of altering the permeability of the cytoplasmic membrane and impairing RNA synthesis, which occur with vancomycin, have not been described with teicoplanin.

PHARMACOKINETICS

Bioavailability 

Teicoplanin is not absorbed orally and can only be administered parenterally. Unlike vancomycin, intramuscular administration is well tolerated. The drug is 90% bound to plasma proteins (albumin) and binding appears linear with rising concentrations . Teicoplanin’s volumes of distribution (Vd) are 0.07–0.11 (initial phase), 1.3–1.5 (distribution phase), and 0.9–1.6 (steady state) l/kg, the values being greater in studies with longer sampling periods. Studies before 1990 used shorter sampling times and so reported lower values for the Vd. The kinetics of distribution is not dependent on teicoplanin dose. The pharmacokinetics of teicoplanin follows a triexponential decay, the alpha, beta, and gamma half-lives being 0.4– 1 hour, 4.7–15.4 hours, and 83–168 hours, respectively.The long serum half-life (88–182 hours) reflects its large molecular size, high protein binding, and extensive tissue distribution.

CLINICAL USES

In general, teicoplanin may be used for indications similar to those for vancomycin. The potential advantages of teicoplanin include its once-daily administration, short infusion time or bolus i.v. administration, feasibility of i.m. dosing, and fewer side effects. However, resistant organisms may be more likely to emerge during therapy with this drug than with vancomycin. In some countries, teicoplanin is reserved for infections in patients who do not tolerate vancomycin. The use of teicoplanin has also been clouded by the initial recommendation of lower doses than are now considered necessary to reliably achieve 610 Glycopeptides and Lipopeptides clinical efficacy in a range of serious infections, especially those involving S. aureus – these important dosing issues are discussed in detail earlier under 4. Mode of drug administration and dosage. Furthermore, teicoplanin has not yet been licensed for use in the USA.

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