Table 4.

General features of older and newer antibiotics with activity against MRSA

Antibiotic	Dosage	Route of administration	Mode of action	Tissue penetration	Use in special population	Strengths	Limitations
Older antibiotics
Vancomycin53	500 mg iv infusion for 60 minutes every 6 hours or 1 g iv infusion for 100 minutes every 12 hours	Intravenous	Bactericidal glycopeptide	8%–10%	Dose titration in patients with renal impairment	Gold standard for MRSA infections. Established efficacy and tolerability	Emerging resistance. Increasing MIC Poor tissue penetration
Clindamycin53	IV: 0.6–2.7 g infusion for 10–60 minute daily in 2–4 divided doses Oral: 150–300 mg every 6 hours, up to 450 mg in severe infections	Intravenous/oral	Bacteriostatic	95%	No dose adjustment in patients with renal impairment	Preferred agent for necrotizing fasciitis as it blocks bacterial toxin production	Emerging resistance Clostridium difficile-associated colitis
Cloxacillin122	Oral: 0.5 g every 6 hours IV: 1–2 g every 6 hours 2 g every 4 hours in case of severe infections	Oral/intravenous	Bactericidal	NA	No dose adjustment in patients with renal impairment	Main stream agent of treating methicillin-susceptible Staphylococcus aureus (MSSA)	Lack of efficacy against MRSA infections
Newer antibiotics
Linezolid123	600 mg IV or orally every 12 hours	Intravenous/oral	Bacteriostatic	105%	No dose adjustment in patients with renal impairment	Bioavailable as oral formulation Preferred agent for necrotizing fasciitis as it inhibits bacterial toxin production	Risk of toxicity with prolonged use Oral switch
Daptomycin124	4–6 mg/kg every 24 or 48 hours	Intravenous	Bactericidal	68%	No dose adjustment in patients with renal impairment	Once-daily iv regimen suitable for outpatient use	Emerging resistance
Tigecycline125	50 or 100 mg every 12 hours	Intravenous	Bacteriostatic	91%	No dose adjustment in patients with renal impairment	Broad spectrum activity against multidrug resistant Gram- positive and Gram-negative pathogens	Low serum levels
Ceftaroline126	600 mg iv infusion for 60 minutes every 12 hours	Intravenous	Bactericidal	NA	Dose titration in patients with renal impairment. No dose adjustments in obese patients	Good clinical efficacy and tolerability. Low propensity for C. difficile- related diarrhea	Low activity against Gram negative pathogens. Bid or tid dosing
Tedizolid127	200 mg iv infusion for 60 minutes, once daily Oral: 200 mg once daily	Intravenous/ oral	Bacteriostatic	NA	No dose adjustment in patients with renal impairment	Bioavailable as oral formulation Preferred agents for necrotizing fasciitis as it inhibits bacterial toxin production	Lower risk of myelotoxicity and drug–drug interactions. Oral switch
Dalbavancin68*	1,000 mg iv infusion for 30 minutes	Intravenous	Bactericidal	NA	Dose titration in patients with renal impairment	Long half-life allowing once-daily iv administration suitable for outpatient use	Low activity against Gram negative pathogens. Cannot be cleared by hemodialysis in case of toxicity Early discharge
Oritavancin68*	1,200 mg single dose iv infusion for over 3 hours	Intravenous	Bactericidal	NA	Dose titration in patients with renal impairment	Long half-life allowing once-daily iv administration	Low activity against Gram negative pathogens

Notes: Dosage approved in Singapore mentioned in the table, except for dalbavancin and oritavancin.

^*Dalbavancin and oritavancin are not approved in Singapore.

Abbreviations: MIC, minimum inhibitory concentration; MRSA, methicillin-resistant Staphylococcus aureus; NA, not available.