Fluconazole: comparison of pharmacokinetics, therapy and in vitro susceptibility

Fluconazole shows good penetration into the tissues and body fluids examined and a rapid equilibrium is achieved between the concentrations in the various compartments. The pharmacokinetics of fluconazole after intravenous or oral administration are proportional to the dose. This finding, together with the slow elimination of the triazole (t1/2 30 h), makes it easier to forecast the therapeutically effective dosage. Measurements of fluconazole concentration in blood can be used to predict levels in some tissues (lung, brain, gynaecological samples), body fluids (sputum, saliva, vaginal secretions) or exudates. Concentrations in cerebrospinal fluid and vitreous humour of the eye reach approximately 80% of the levels found in blood. A very high proportion of fluconazole is excreted unchanged in the urine, where concentrations of the drug are 10-20-fold higher than in blood. Whilst this pharmacokinetic profile is valuable in the treatment of fungal infections of the urinary tract, it also means that the dosage may need to be decreased in patients with renal impairment. The susceptibility of fungi to fluconazole in vitro and in vivo correlates well with the concentrations of the drug measured in various compartments of the body.

Pharmacokinetics of miconazole in serum and exudate of pelvic retroperitoneal space after radical hysterectomy and pelvic lymphadenectomy

Due to the increased number of compromised hosts with fungal infections, doctors have recently started prescribing antifungal agents. In the field of gynecology, however, the choice of which drug to use has been difficult. The efficacies of these drugs depend on their antifungal spectra, potencies and concentrations in tissues. The present study was designed to investigate the pharmacokinetics of miconazole in the exudate of the retroperitoneal space that is formed after radical hysterectomy and pelvic lymphadenectomy. A total of 600 mg of miconazole was administered to the patients for exactly 60 min using an automatic drip-infusion pump. The parameters of the formulas analyzed by the two-compartment model were determined using the least-squares method, and a simulation curve was made. The maximum drug concentration (Cmax) of miconazole in serum was 6.26 mg/l 1 h after drip infusion commencement and the t1/2 in serum was 8.86 h. The value of the area under the time-serum concentration curve (AUC) in serum was 19.13 mg/h per l. The Cmax of miconazole in the exudate of the retroperitoneal space was 0.13 mg/l 2.48 h after the drip infusion was started. The value of AUC in the exudate was 2.52 mg/h per l.

[Fluconazole: comparison of pharmacokinetics, therapy and in vitro susceptibility of yeasts]

Fluconazole penetrates well into the tissues and body fluids which were examined and achieves rapid equilibration between the different compartments. The pharmacokinetics of fluconazole are independent of the dose after oral or intravenous administration. This finding, together with the drug's slow elimination (t1/2 30 h) facilitate the estimation of the therapeutically effective dosage. The concentrations of fluconazole measured in blood can be extrapolated to the concentrations in tissue (lung, brain, gynecological tissues), body fluids (sputum, saliva, vaginal secretions) and exudates. The concentration of fluconazole in cerebrospinal fluid and in the vitreous humour of the eye is ca. 80% of that in blood. Fluconazole is predominantly excreted in the urine in the unchanged form, which explains the 10 to 20 fold higher concentration of the drug in urine relative to blood. Although this pharmacokinetic profile favours the use of fluconazole in mycotic infections of the urinary tract it also means that the dose of the drug may have to be adapted to lower regimens in the systemic treatment of patients with restricted kidney function. The in vitro and in vivo susceptibility of the yeasts correlates with the concentrations of fluconazole measured in the different compartments of the body.