2 In some cases of myopathy involving raised CPK and muscle symptoms, the patients also presented with elevated transaminases. These transaminase increases were likely to be related to the skeletal muscle effects. The majority of transaminase elevations were of Grade 13 toxicity and resolved upon discontinuation of treatment.
3 When clinical information on the patients was available to make a judgement, approximately 50% of the cases occurred in patients with pre-existing renal impairment, or in those receiving concomitant medicinal products known to cause rhabdomyolysis.
The safety data for the administration of daptomycin via 2-minute intravenous injection are derived from two pharmacokinetic studies in healthy volunteers. Based on these study results, both methods of daptomycin administration, the 2-minute intravenous injection and the 30-minute intravenous infusion, had a similar safety and tolerability profile. There was no relevant difference in local tolerability or in the nature and frequency of adverse reactions.
4.9 Overdose
In the event of overdose, supportive care is advised. Daptomycin is slowly cleared from the body by haemodialysis (approximately 15% of the administered dose is removed over 4 hours) or by peritoneal dialysis (approximately 11% of the administered dose is removed over 48 hours).
5. PHARMACOLOGICAL PROPERTIES
5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Antibacterials for systemic use, Other antibacterials, ATC code: J01XX09
Mechanism of action
Daptomycin is a cyclic lipopeptide natural product that is active against Gram positive bacteria only.
The mechanism of action involves binding (in the presence of calcium ions) to bacterial membranes of both growing and stationary phase cells causing depolarisation and leading to a rapid inhibition of protein, DNA, and RNA synthesis. This results in bacterial cell death with negligible cell lysis.
PK/PD relationship
Daptomycin exhibits rapid, concentration dependent bactericidal activity against Gram positive organisms in vitro and in in vivo animal models. In animal models AUC/MIC and Cmax/MIC correlate with efficacy and predicted bacterial kill in vivo at single doses equivalent to human doses of 4 mg/kg and 6 mg/kg once daily.
Mechanisms of resistance
Strains with decreased susceptibility to daptomycin have been reported especially during the treatment of patients with difficult-to-treat infections and/or following administration for prolonged periods. In particular, there have been reports of treatment failures in patients infected with Staphylococcus aureus, Enterococcus faecalis or Enterococcus faecium, including bacteraemic patients, that have been associated with the selection of organisms with reduced susceptibility or frank resistance to daptomycin during therapy.
The mechanism(s) of daptomycin resistance is (are) not fully understood.
Breakpoints
Minimum inhibitory concentration (MIC) breakpoint established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST) for Staphylococci and Streptococci (except S. pneumoniae) are Susceptible 1 mg/l and Resistant > 1 mg/l.
Susceptibility
The preva lence of resistance may vary geographically and over time for selected species and local information on resistance is desirable, particularly when treating severe infections. As necessar
