Busulfan target exposure attainment in children undergoing allogeneic hematopoietic cell transplantation: a single day versus a multiday therapeutic drug monitoring regimen.

Busulfan exposure has previously been linked to clinical outcomes, hence the need for therapeutic drug monitoring (TDM). Study objective was to evaluate the effect of day 1 TDM-guided dosing (regimen d1) versus days 1 + 2 TDM-guided dosing (regimen d1 + 2) on attaining adequate busulfan exposure. In this observational study, we included all children receiving busulfan-based allogeneic hematopoietic cell transplantation. Primary outcome was the percentage of patients achieving busulfan target attainment in both TDM regimens. Secondary outcomes were the variance in busulfan exposure and day-4 clearance (Clday4) estimates between both TDM regimens and dosing day 1 and 2. In regimen d1, 84.3% (n = 91/108) attained a therapeutic busulfan exposure, while in regimen d1 + 2 a proportion of 90.9% was found (n = 30/33, not-significant). Variance of Clday4 estimate based on busulfan day 2 concentrations was significantly smaller than the variance of Clday4 estimates based on day 1 concentrations (p < 0.001). Therefore, day 1-guided TDM (pharmacometric model-based) of busulfan may be sufficient for attaining optimal target exposure, provided that subsequent TDM is carried out if required. However, performing TDM on subsequent days may be beneficial, as measurements on day 2 seemed to reduce the variance in the estimated clearance as compared to day 1 sampling.

Invasive Candidiasis in the Elderly: Considerations for Drug Therapy.

Candida infections in the elderly are an important and expanding clinical problem, with significantly higher mortality in this group than in younger patients. The increasing problem of invasive Candida infections may be related to higher prevalence of immunocompromised older people and the emergence of treatment resistance. Older people, especially the frail and critically ill, are at higher risk of medication-related harmful effects due to changes in pharmacokinetics and pharmacodynamics, which may be further complicated by organ dysfunction, diminished homeostatic control, co-morbidities and polypharmacy. Here, we review the available options for the treatment of Candida infections and provide insights into the challenges surrounding the optimal use of antifungal drugs in the elderly.

Plasma concentrations of caspofungin at two different dosage regimens in a patient with hepatic dysfunction.

The currently recommended dosage regimen of caspofungin (50 mg/day) was developed for patients with invasive candidiasis. With invasive aspergillosis, successful outcomes occur in less than half the patients. We evaluate the pharmacokinetics in a patient with elevated liver enzyme levels after liver transplantation, who received caspofungin for the treatment of aspergillosis. Plasma concentrations of caspofungin were monitored at 2 different dosage regimens. The area under the concentration-time curve (AUC) at a dosage of 70 mg was 191 mg h/L and was associated with an increase in liver enzymes. After dose reduction to 50 mg with an AUC of 100 mg h/L, liver enzymes normalized. In conclusion, caspofungin plasma concentrations may be helpful to evaluate exposure and reduce the need for off-label dosing.