Glycopeptides

This is the outline on Glycopeptides by Anell West and Ashley Walter. Let us know if we missed something important or need to correct anything please! 

Three types of glycopeptide antibiotics are Teicoplanin, Telavancin and Vancomycin.

Vancomycin is a glycopeptide bactericidal antibiotic used to treat staphylococcal infections. Used against drug-resistant S. aureus and in cardiac surgical prophylaxis with patients with penicillin allergies. Serum vanco levels need to be monitored. Vancomycin is ineffective for treating enterococci.

Telavancin is a glycopeptide used to treat gram-positive bacteria and skin infections. This drug is a semisynthetic derivative of Vancomycin, with bacterial action against MRSA. Telavancin has an advantage of once daily dosing.

Action: This class of drugs inhibits the synthesis of cell walls in susceptible microbes by inhibiting peptidoglycan synthesis. They bind to the amino acids within the cell wall preventing the addition of new units to the peptidoglycan. In particular, they bind to acyl-D-alanyl-D-alanine in peptidoglycan.

Pharmacokinetics: Vancomycin is given orally for treatment of staphylococcal enterocolitis and antibiotic associated pseudomembranous colitis due to c. diff. Vancomycin is given IV for severe infections due to MRSA, septicemia, and bone, skin, and lower respiratory tract infections that do not respond or are resistant to other antibiotics.

Pharmacodynamics: Vancomycin inhibits bacterial cell wall synthesis and is active against several gram-positive microorganisms. The peak action is 30 minutes after the end of the infusion.

Side effects/adverse reactions: Vancomycin may cause neprotoxicity and ototoxicity. Ototoxicity results in damage to the auditory or vestibular branch of the cranial nerve VIII. This can result in permanent hearing loss or temporary or permanent loss of balance. Side effects may include: chills, dizzy, fever, rash, N/V, thrombophlebitis at the injection site. Too rapid injection can cause red man syndrome or red neck syndrome, which consists of red blotching of the face, neck, and chest. This is a toxic effect not an allergic reaction. Most patients tolerate slowing the infusion rate to over 1 hour. Other adverse effects include, eosinophilia, neutropenia, tachycardia, generalized tingling, and cardiac arrest

Drug interactions: Dimenhydrinate (Dramamine) when taken with Vancomycin can mask ototoxicity. The risk of nephrotoxicity and ototoxicity can be potentiated when Vancomycin is given with Lasix, aminoglycosides, amphotericin B, colistin, cisplatin, and cyclosporine. Vancomycin may inhibit methotrexate excretion and increase methotrexate toxicity. The absorption of oral Vancomycin may decrease when given with cholestyramine and colestipol.

Administration:

Vancomycin is usually given intravenously, as an infusion, and can cause tissue necrosis and phlebitis at the injection site if given too rapidly. Over 90% of the dose is excreted in the urine; therefore there is a risk of accumulation in patients with renal impairment, so therapeutic drug monitoring (TDM) is recommended.

Oral preparations of vancomycin are available, however they are not absorbed from the lumen of the gut, so are of no use in treating systemic infections. The oral preparations are formulated for the treatment of infections within the gastrointestinal tract such as, Clostridium difficile.