Diflucan
Pharmacoeconomic analysis of oral antifungal therapies used to treat dermatophyte onychomycosis of the toenails. A US analysis.

Gupta AK.

Department of Medicine, Sunnybrook Health Science Center, Toronto, Ontario, Canada. agupta execulink.com

Until a few years ago, griseofulvin and ketoconazole were the only 2 oral agents available for the treatment of dermatophyte onychomycosis of the toenails. With the availability of the newer antifungal agents, such as itraconazole, terbinafine and fluconazole, the armamentarium of drugs available to treat onychomycosis has expanded. The objective of this study was to determine the relative cost effectiveness of the most commonly used oral antifungal agents in the US for the treatment of dermatophyte onychomycosis of the toenails from the perspective of a third-party payer. The time horizon was 3 years. A 5-step approach was used in this pharmacoeconomic analysis. First, the purpose of the study, the comparator drugs and their dosage regimens were defined. In step II, the medical practice and resource-consumption patterns associated with the treatment of onychomycosis were identified. In step III, a meta-analysis was performed on all studies meeting prespecified criteria, and the mycological cure rates of the comparator drugs were determined. In step IV, the treatment algorithm for the management of onychomycosis was constructed for each drug. The cost-of-regimen analysis for each comparator incorporated the drug acquisition cost, medical-management cost and cost of managing adverse drug reactions. The expected cost per patient, number of symptom-free days (SFDs), cost per SFD and the relative cost effectiveness for the comparator drugs were calculated. In step V, a sensitivity analysis was performed. The drug comparators for this study were griseofulvin, itraconazole (continuous and pulse), terbinafine and fluconazole. The mycological cure rates [mean +/- standard error (SE)] from the meta-analysis were griseofulvin 24.5 +/- 6.7%, itraconazole (continuous) 66.4 +/- 6.1%, itraconazole (pulse) 76 +/- 9.3%, terbinafine 74 +/- 7% and fluconazole 59%. The cost per mycological cure was griseofulvin $US8089, itraconazole (continuous) $US1877, itraconazole (pulse) $US991, terbinafine $US1125 and fluconazole $US1506. The corresponding cost per SFD was griseofulvin $US7.05, itraconazole (continuous) $US2.18, itraconazole (pulse) $US1.26, terbinafine $US1.28 and fluconazole $US2.12. The resulting ratios of cost per SFD relative to itraconazole (pulse) [1.00] were terbinafine 1.02, itraconazole (continuous) 1:73, fluconazole 1.69 and griseofulvin 5.62. In conclusion, in this analysis, itraconazole (pulse) and terbinafine were the most cost-effective therapies for dermatophyte onychomycosis of the toenails, both being substantially more cost effective than griseofulvin.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10178650&dopt=Abstract fluconazole Diflucan



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Antifungal and immunoadjuvant properties of fluconazole in mice immunosuppressed with morphine.

Di Francesco P, Gaziano R, Casalinuovo IA, Palamara AT, Favalli C, Garaci E.

Department of Experimental Medicine and Biochemical Sciences, University of Rome, Italy.

We investigated the efficacy of fluconazole on experimental disseminated candidiasis in mice immunocompromised by chronic morphine treatment. CD1 mice were severely immunosuppressed by repeated morphine administrations, i.e., subcutaneous (s.c.) injections of 75 mg/kg/day, 3 days before and 5 days after a systemic Candida albicans infection induced by intravenous administration of 1 x 10(6) fungal cells/mouse. Fluconazole (2.5 mg/kg, s.c., at 6, 24 and 48 h postinfection) was very effective in prolonging survival time of morphine-treated mice. Fluconazole treatment also promotes a recovery of killing activity of polymorphonuclear leukocyte cells suppressed by morphine administrations.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9142461&dopt=Abstract fluconazole Diflucan



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Pharmacokinetics of oral fluconazole when used for prophylaxis in bone marrow transplant recipients.

El-Yazigi A, Ellis M, Ernst P, Spence D, Hussain R, Baillie FJ.

Department of Biological and Medical Research, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.

The pharmacokinetics of fluconazole was investigated in 20 bone marrow transplant patients following oral administration of 200 mg of this drug. Blood samples were collected from each patient at different time intervals within 48 h after the first dose, and fluconazole was measured in plasma by high-performance liquid chromatography with UV detection. Urine was collected from 14 of these patients and analyzed similarly. The plasma concentration-time data exhibited the characteristics of the one-compartment model with first-order absorption quite well. The means +/- standard deviations of half-lives for absorption and elimination, peak concentration, time to peak, mean residence time, apparent volumes of distribution, area under the curve, and apparent oral clearance observed in these patients were 2.84 +/- 1.34 h, 19.94 +/- 18.7 h, 4.45 +/- 1.86 microg/ml, 8.34 +/- 5.97 h, 39.57 +/- 20.5 h, 0.874 +/- 0.48 liter/kg, 156.0 +/- 60.6 microg x h/ml, and 0.0256 +/- 0.0138 liter/h x kg, respectively. The amount of fluconazole excreted in urine in 24 h was 67.1 +/- 83 mg, which represents 33.55% +/- 41.6% of the dose administered. Patients who developed hemorrhagic cystitis excreted significantly (P < or = 0.0094) more fluconazole in 24 h than did those who did not.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9145843&dopt=Abstract fluconazole Diflucan



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Metabolism of rifabutin and its 25-desacetyl metabolite, LM565, by human liver microsomes and recombinant human cytochrome P-450 3A4: relevance to clinical interaction with fluconazole.

Trapnell CB, Jamis-Dow C, Klecker RW, Collins JM.

Center for Drug Evaluation and Research, Food and Drug Administration, Rockville, Maryland 20852, USA. trapnell a1.cber.fda.gov

Rifabutin and fluconazole are often given concomitantly as therapy to prevent opportunistic infections in individuals infected with the human immunodeficiency virus. Recent reports have shown increased levels of rifabutin and its 25-desacetyl metabolite, LM565, in plasma when rifabutin is administered with fluconazole. Since fluconazole is known to inhibit microsomal enzymes, this study was undertaken to determine if this rifabutin-fluconazole interaction was due to an inhibition of human hepatic enzymes. The metabolism of both rifabutin and LM565 was evaluated in human liver microsomes and recombinant human cytochrome P-450 (CYP) 3A4 in the presence of fluconazole and other probe drugs known to inhibit CYP groups 1A2, 2C9, 2D6, 2E1, and 3A. The concentrations of rifabutin (1 microg/ml), LM565 (1 microg/ml), and fluconazole (10 and 100 microg/ml) used were equal to those observed in plasma after the administration of rifabutin and fluconazole at clinically relevant doses. High-performance liquid chromatography was used to assess the metabolism of rifabutin and LM565. Rifabutin was readily metabolized to LM565 by human microsomes, but the reaction was independent of NADPH and was not affected by the P-450 inhibitors. No rifabutin metabolism by recombinant CYP 3A4 was found to occur. LM565 was also metabolized by human microsomes to two products, but metabolism was dependent on NADPH and was affected by certain P-450 inhibitors. In addition, LM565 was readily metabolized by the recombinant CYP 3A4 to the same two products found with its metabolism by human microsomes. Therefore, rifabutin is metabolized by human microsomes but not via cytochrome P-450 enzymes, whereas LM565 is metabolized by CYP 3A4.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9145845&dopt=Abstract fluconazole Diflucan



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Combination therapy with fluconazole and flucytosine in the murine model of cryptococcal meningitis.

Nguyen MH, Najvar LK, Yu CY, Graybill JR.

University of Florida College of Medicine, Gainesville VA Medical Center, USA. nguyen.med shands.ufl.edu

This study elucidates the role of combined fluconazole and flucytosine as therapy for cryptococcosis in the murine model of meningitis. Three strains of Cryptococcus neoformans for which the range of fluconazole MICs was wide--2 microg/ml (susceptible strain), 8 microg/ml (moderately susceptible strain), and 32 microg/ml (resistant strain)--were used for infection. One day postinfection, the mice were randomized into eight treatment groups: placebo; flucytosine (40 mg/kg of body weight/day); fluconazole at 3 mg/kg/day (low dosage), 10 mg/kg/day (moderate dosage), or 20 mg/kg/day (high dosage); and combined flucytosine and fluconazole at low, moderate, or high doses of fluconazole. Three major findings were demonstrated: (i) correlation between the MICs for the isolates and the in vivo effectiveness of fluconazole as assessed by the reduction in cryptococcal brain burden, (ii) a dose-response curve (a higher dose of fluconazole was significantly more efficacious than a lower dose [P < 0.001]), and (iii) synergism between fluconazole and flucytosine (therapy with a combination of fluconazole and flucytosine was superior to therapy with either agent alone [P < 0.01]).

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9145879&dopt=Abstract fluconazole Diflucan



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Effects of incubation time and buffer concentration on in vitro activities of antifungal agents against Candida albicans.

Tornatore MA, Noskin GA, Hacek DM, Obias AA, Peterson LR.

Department of Pathology, Northwestern Memorial Hospital and Northwestern University Medical School, Chicago, Illinois 60611, USA.

Nine selected isolates of Candida albicans were tested for their susceptibilities to amphotericin B and fluconazole by using three methods to assess the effect of incubation time and buffer concentration. By using a microdilution method with 0.0165 M 3-(N-morpholino)propanesulfonic acid (MOPS) and a 24-h incubation time, all of the isolates were found to be susceptible to amphotericin B and fluconazole. After 48 h of incubation, all isolates were still susceptible to amphotericin B. Seven of the nine isolates were resistant to fluconazole, and for the remaining two isolates, MICs increased by fourfold or more but the isolates remained susceptible (MIC, < or = 10 microg/ml). The nine isolates, along with three control strains, were further tested against amphotericin B and fluconazole by a standard broth macrodilution method with both 0.165 and 0.0165 M MOPS. The susceptibility results for fluconazole by the broth macrodilution method with the lower MOPS concentration correlated with the results of the 24-h broth microdilution method for determination of susceptibility or resistance in eight of nine tests and with the results of the 48 h broth microdilution method in three of nine tests. The results of the broth macrodilution method with the standard MOPS concentration did not correlate with any of the results obtained by the 24-h broth microdilution but correlated with results of seven of nine tests by the 48-h broth microdilution method. All nine test strains appeared to be susceptible when they were examined by a flow cytometric method. For clinical yeast susceptibility testing in microdilution panels, the 0.0165 M MOPS concentration combined with 24 h of incubation appeared to be the method of choice. The lower MOPS concentration may also be a useful modification to the tentative broth macrodilution method of the National Committee for Clinical Laboratory Standards. Use of the higher buffer concentration or longer incubation time may lead to false in vitro resistance for agents like fluconazole.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9163465&dopt=Abstract fluconazole Diflucan



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Combination therapy with amphotericin B and fluconazole against invasive candidiasis in neutropenic-mouse and infective-endocarditis rabbit models.

Sanati H, Ramos CF, Bayer AS, Ghannoum MA.

Department of Internal Medicine, Harbor-UCLA Medical Center, Torrance, California 90509, USA.

Although there are an increasing number of new antifungal agents available, the morbidity and mortality due to invasive mycoses remain high. The high rates of polyene toxicities and the development of azole resistance have raised the issue of using antifungal agents of these classes in combination, despite theoretical concerns regarding antagonism between such agents. This study was designed to evaluate the in vivo efficacy of combined therapy with amphotericin B and fluconazole against Candida albicans. Two distinct animal models were used in this study: a neutropenic-mouse model of hematogenously disseminated candidiasis and the infective-endocarditis rabbit model. Treatment efficacy was assessed by determining reductions in mortality as well as decreases in tissue fungal densities. In the neutropenic-mouse model, amphotericin B, as well as combination therapy, significantly prolonged survival compared to untreated controls (P < 10(-5) and P = 0.001, respectively). The fungal densities in the kidneys of neutropenic mice were significantly reduced with either amphotericin B monotherapy or amphotericin B-fluconazole combined therapy compared to those of controls (P < 10(-6)). Fluconazole monotherapy also reduced fungal densities in the kidneys; however, this decrease was not statistically significant (P = 0.17). In contrast, treatment with either fluconazole alone or combined with amphotericin B (but not amphotericin B monotherapy) significantly decreased fungal densities in the brain (P = 0.025). In the rabbit endocarditis model, amphotericin B monotherapy or combined therapy significantly decreased fungal densities in cardiac vegetations (P < 0.01 versus the controls). Although no significant antagonism was seen when fluconazole was given in combination with amphotericin B, combination therapy did not augment the antifungal activity of amphotericin B.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9174196&dopt=Abstract fluconazole Diflucan



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Fluconazole concentrations in pulmonary tissue and pericardial fluid.

Rieder-Nelissen CM, Hasse J, Yeates RA, Sarnow E.

Abteilung Pneumologie, Johannes-Gutenberg-Universitat, Mainz, Germany.

In order to investigate the clinical efficacy of the triazole antifungal agent fluconazole (FCA) in the treatment of pulmonary mycosis, in the present study the concentrations of fluconazole in human pulmonary tissue, pericardial fluid and serum were determined at 1, 2, 12 and 13 h after intravenous administration of fluconazole 200 mg. The mean FCA concentrations in the serum were 4.04 mg/l (1 h), 3.82 mg/l (2 h), 2.35 mg/l (12 h) and 2.13 mg/l (13 h). The respective FCA levels in the pulmonary tissue were 4.64 mg/kg, 4.54 mg/kg; 3.50 mg/kg and 3.40 mg/kg and the concentrations in the pericardial fluid were 3.86 mg/l, 3.57 mg/l, 2.35 mg/l and 2.13 mg/l. The FCA concentrations in the pulmonary tissue that were statistically significant higher than the serum concentrations were found at 2 h, 12 h and 13 h after intravenous administration (p < 0.05).

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9181393&dopt=Abstract fluconazole Diflucan