The bis
triazole agent
fluconazole is used widely in the treatment of superficial and deep
mycoses. A single oral dose of
fluconazole 150 mg gives a mean long term clinical cure rate of 84 +/- 5% and is considered a valuable alternative to other topical antifungal drugs for vaginal
candidiasis. A clinical cure rate of 90.4% for oropharyngeal
candidiasis was obtained with 100mg daily for a minimum of 14 days; however, as for the other
azoles the rate of relapse was large (40%) in immunocompromised patients. A daily dose of 100mg for at last 3 weeks gave satisfying outcomes for oesophageal
candidiasis. Most patients (71 to 86%) with signs and symptoms of urinary tract
candidiasis show beneficial clinical results when given oral
fluconazole 50mg for several weeks.
Fluconazole 50 to 150 mg given for weeks or months results in over 90% clinical cure or improvement for cutaneous mycosis including
tinea,
pityriasis,
cryptococcosis and
candidiasis. Prolonged (6 to 12 months)
fluconazole 150 mg once a week is needed to treat
onychomycosis successfully. Higher oral doses (200 to 400 mg daily) for long periods are generally used to treat deep
mycoses such as
meningitis, ophthalmitis,
pneumonia, hepatosplenic mycosis and
endocarditis.
Fluconazole is effective for treating the fungal
peritonitis which can complicate
continuous ambulatory peritoneal dialysis (
CAPD). A regimen of 50 mg intraperitoneally or 100 mg orally was used in these patients with impaired renal function. The dosage schedules used to treat
disseminated fungal infections due to systemic
mycoses with different or multiple foci of
infections vary widely, with doses of 50 to 400 mg given orally or intravenously for between 1 week and several months. The most recent clinical reports have investigated the use of prophylaxis with
fluconazole 100 to 400 mg daily, in immunocompromised patients.
Fluconazole is found in body fluids such as vaginal secretions, breast milk, saliva, sputum and cerebrospinal fluid at concentrations comparable with those determined in blood after single or multiple doses. There is an excellent linear plasma concentration-dose relationship, but the mycological and clinical responses do not appear to be well correlated with the dose. A total maximum daily dose of 1600 mg is recommended to avoid neurological toxicity. Data from pharmacokinetic studies conducted in patients, mainly those with
AIDS, and using a 1-compartment model give very constant parameters similar to those obtained in healthy individuals. Bioavailability, measured in HIV-positive patients and those with
AIDS, exceeded 93% for
tablets,
suspension and
suppositories. The time to reach peak plasma concentrations (tmax) was 2.4 to 3.7 hours. The peak plasma
drug concentration (Cmax) obtained after a 100 mg oral dose was 2 mg/L. Areas under the concentration-time curve (AUC) obtained in different studies all correlate well with the dose (r = 0.926). The AUC determined after 200 and 25 mg
suppositories were similarly well correlated.
Hypochlorhydria does not affect the absorption of
fluconazole, neither does food intake, race (Japanese or Caucasian) or gastrointestinal resection. Binding to
plasma protein is low (11.14%) and is increased to 23% in
cancer patients.
Fluconazole is rapidly distributed to the tissue, where it accumulates. Tissues fall into 1 of 4 groups of increasing
drug concentration: blood, bone and brain have the lowest concentrations, and spleen has the highest. The volume of distribution (Vd) remains stable at 46.3 +/- 7.9L and is considered to be an 'invariant' parameter across species.
Fluconazole is poorly metabolised and is mainly eliminated unchanged in the urine. The percentage of the dose recovered in the urine in 48 hours is close to 60%. Concentrations in the urine are high and the half-life (t1/2) is long (37.2 +/- 5.5h) in patients, mainly those with
AIDS, which is not significantly different from the t1/2 (31.4 +/- 4.7 hours) in healthy individuals. (ABSTRACT TRUN