Population Pharmacokinetic Model and Meta-analysis of Outcomes of Amphotericin B Deoxycholate Use in Adults with Cryptococcal Meningitis.

There is a limited understanding of the population pharmacokinetics (PK) and pharmacodynamics (PD) of amphotericin B deoxycholate (DAmB) for cryptococcal meningitis. A PK study was conducted in n = 42 patients receiving DAmB (1 mg/kg of body weight every 24 h [q24h]). A 2-compartment PK model was developed. Patient weight influenced clearance and volume in the final structural model. Monte Carlo simulations estimated drug exposure associated with various DAmB dosages. A search was conducted for trials reporting outcomes of treatment of cryptococcal meningitis patients with DAmB monotherapy, and a meta-analysis was performed. The PK parameter means (standard deviations) were as follows: clearance, 0.03 (0.01) × weight + 0.67 (0.01) liters/h; volume, 0.82 (0.80) × weight + 1.76 (1.29) liters; first-order rate constant from central compartment to peripheral compartment, 5.36 (6.67) h-1; first-order rate constant from peripheral compartment to central compartment, 9.92 (12.27) h-1 The meta-analysis suggested that the DAmB dosage explained most of the heterogeneity in cerebrospinal fluid (CSF) sterility outcomes but not in mortality outcomes. Simulations of values corresponding to the area under concentration-time curve from h 144 to h 168 (AUC144-168) resulted in median (interquartile range) values of 5.83 mg · h/liter (4.66 to 8.55), 10.16 mg · h/liter (8.07 to 14.55), and 14.51 mg · h/liter (11.48 to 20.42) with dosages of 0.4, 0.7, and 1.0 mg/kg q24h, respectively. DAmB PK is described adequately by a linear model that incorporates weight with clearance and volume. Interpatient PK variability is modest and unlikely to be responsible for variability in clinical outcomes. There is discordance between the impact that drug exposure has on CSF sterility and its impact on mortality outcomes, which may be due to cerebral pathology not reflected in CSF fungal burden, in addition to clinical variables.

Trending serial CSF samples to guide treatment of refractory coccidioidal meningitis with intrathecal liposomal amphotericin.

Intrathecal amphotericin B deoxycholate (AmB-d) can be prescribed as an adjunct to systemic therapy for severe or recalcitrant cases coccidioidal meningitis. Recently intravenous (IV) Liposomal amphotericin B (L-AmB) has been recommended as monotherapy therapy for refractory coccidioidal meningitis based on its advantages over (AmB-d), however, its intrathecal use has not been reported. Moreover, there is nothing in the literature quantifying clinical improvement with objective laboratory data in human patients. Consequently, there are no guidelines on how to monitor regularly for improvement of coccidioidal meningitis with treatment of intrathecal L-AmB. The present case addresses both of these. We report intrathecal use of L-AmB for refractory coccidioidal meningitis. Our data demonstrate that there is a correlation between clinical improvement and a decrease in cerebrospinal fluid (CSF) white blood cells (WBC's), protein, and coccidioidal titers with treatment of intrathecal L-AmB with serial collection of CSF studies at the same site, in our case via collection through an external ventricular drain (EVD). As a result, one may postulate that serial CSF collection can be used to monitor the treatment of coccidioidal meningitis; however this case also addresses the risk of developing ventriculitis with sustained EVD placement.