Glycopeptide antibiotics are antibacterial agents that have been in clinical use since the late 1950s, and are indicated for the treatment of severe infection caused by gram-positive bacteria (Hansen et al, 2022). Glycopeptide's mechanism of action is to inhibit bacterial cell wall synthesis, resulting in cell death.
Vancomycin and teicoplanin are the most commonly used glycopeptides in clinical practice. Vancomycin is indicated for the treatment of septicaemia, infective endocarditis, skin and bone infection, and lower respiratory tract infection. Teicoplanin has bactericidal activity against multi-resistant staphylococci infection.
Red man syndrome
Vancomycin and teicoplanin can cause a type of hypersensitivity reaction known as ‘red man syndrome’. Red man syndrome has been associated with rapid infusion of the first dose of the drug. It typically develops 5–10 minutes after administration and is characterised by itching and flushing of the face, neck and upper chest.
Despite symptoms mimicking an allergic reaction, it is not a true allergy but a non-specific mast cell degranulation. Severe reactions can appear anaphylactoid in nature with hypotension, dyspnoea, pain and muscle spasms over the chest. The risk of red man syndrome can be minimised by intravenously administrating the drug over a longer infusion time.
Therapeutic serum concentration
Glycopeptides can be toxic to the kidneys and inner ear, with vancomycin associated with a higher incidence of nephrotoxicity than teicoplanin. Nephrotoxicity can include renal failure, impairment and elevated blood creatinine. Ototoxicity can be transient or permanent. Initial vancomycin dosage is based on body weight, with serum vancomycin levels measured to assess adequate therapeutic concentration and avoid toxic dose. Subsequent dosage adjustment should be made, with monitoring frequency dependent on clinical situation.
QUESTION 1
An adult, weight 75 kg, is diagnosed with severe community-acquired pneumonia and prescribed vancomycin. A loading dose of 26 mg/kg (max 2 g) by intravenous infusion is given and a maintenance dose of 20 mg/kg is prescribed. A high vancomycin plasma concentration is obtained, and the maintenance dose is decreased by 10%.
- 1a). What is the loading dose?
- 1b). What is the initial prescribed maintenance dose?
- 1c). What should the reduced maintenance dose be in response to the high serum vancomycin concentration?
QUESTION 2
A neonate aged 32 weeks, weight 1560 g, is diagnosed with bacterial meningitis and prescribed vancomycin. They are prescribed 15 mg/kg every 12 hours to be adjusted in response to serum plasma concentration.
What is the initial prescribed dose?
QUESTION 3
An adult, weight 43 kg, is diagnosed with streptococcal endocarditis and prescribed teicoplanin. They are prescribed 12 mg/kg by intravenous infusion.
What is the initial prescribed dose?
QUESTION 4
A 1-month-old child, weight 7kg, is diagnosed with cellulitis and prescribed teicoplanin. Initial loading dose is 16 mg/kg followed by 8 mg/kg maintenance dose.
4a). What is the initial loading dose?
4b). What is the maintenance dose?