Factors influencing caspofungin plasma concentrations in patients of a surgical intensive care unit

Background. Co-morbidity, medical and surgical interventions often cause alterations to drug plasma concentrations and pharmacokinetic parameters in critically ill patients. In the present study, we investigated parameters influencing plasma caspofungin concentrations in patients of a surgical intensive care unit (SICU). Methods: In a monocentre open study, caspofungin trough concentrations (C-24) were determined for a group of SICU patients. A linear-mixed model was then used to assess factors influencing caspofungin plasma concentrations. Results: A total of 40 SICU patients were enrolled. Age and body weight ranged from 22 to 76 years and 47 to 108 kg, respectively. All participants received a caspofungin loading dose of 70 mg and a maintenance dose of 50 mg/day. The median duration of therapy was 10 days. Caspofungin C-24 in SICU patients varied more than those determined for healthy subjects reported in previous studies (0.52-4.08 mu g/mL versus 1.12-1.78 mu g/mL). According to our model, caspofungin C24 were predicted to be significantly higher in patients with body weight < 75 kg (P = 0.019) and patients with albumin concentration > 23.6 g/L (P = 0.030). Conclusions: Our results show that body weight and albumin concentration influence caspofungin C-24 in SICU patients and should therefore be considered prognostic factors.