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Can fluconazole concentrations in saliva be used for therapeutic drug monitoring?

Koks CH, Crommentuyn KM, Hoetelmans RM, Mathot RA, Beijnen JH.

Department of Pharmacy and Pharmacology, Slotervaart Hospital, Amsterdam, The Netherlands. Apkko slz.nl

The saliva/plasma concentration ratio of fluconazole was investigated in 22 HIV-1-infected individuals with an oropharyngeal Candida infection to determine whether saliva fluconazole concentrations could provide useful information for therapeutic drug monitoring in this population. Steady-state paired plasma and saliva samples were obtained after approximately 1 week of treatment with 50-or 100-mg fluconazole as capsules. A significant correlation between plasma and salivary levels of fluconazole was observed. The median saliva/plasma concentration ratio was 1.3 and was independent of the ingested dose and the plasma fluconazole concentration. The prediction of fluconazole concentrations in plasma from the concentrations in saliva was, although unbiased, not precise. From these findings, the authors conclude that although stimulated salivary fluconazole concentrations are significantly correlated with plasma concentrations, it is not possible to predict plasma fluconazole levels from the salivary concentrations with adequate precision. However, saliva fluconazole concentrations have sufficient value to test for compliance and even semiquantitative prediction of plasma concentrations.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11477332&dopt=Abstract fluconazole Diflucan



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Antifungal triazoles induce malformations in vitro.

Menegola E, Broccia ML, Di Renzo F, Giavini E.

Department of Biology, University of Milan, Italy.

Triazole-derivatives are antimycotics used in agriculture as well as in clinical and veterinary therapy. The aim of the present work is the in vitro comparative study of the teratogenic activity of triazole (the parental compound), flusilazole (an agricultural triazole mono-derivative fungicide), and fluconazole (a clinically used bis-triazole derivative). Rat embryos, 9.5 days old (1 to 3 somites) were exposed in vitro to triazole 500 to 5000 microM, flusilazole 3.125 to 250 microM, or fluconazole 62.5 to 500 microM. After 48 h in culture, the embryos were morphologically examined and processed for histologic and biochemical analysis. Flusilazole and fluconazole showed similar teratogenic effects (abnormalities at the branchial apparatus level and cell death at the level of the branchial mesenchyme) at concentration levels of 6.25 microM and higher for flusilazole and of 125 microM and higher for fluconazole. By contrast, only slight developmental retardation and blood discoloration were observed at the highest concentrations of triazole, suggesting no teratogenic activity for the triazole group.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11489598&dopt=Abstract fluconazole Diflucan



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Expression of ubiquitin gene in Microsporum canis and Trichophyton mentagrophytes cultured with fluconazole.

Kano R, Okabayashi K, Nakamura Y, Watanabe S, Hasegawa A.

Department of Pathobiology, Nihon University School of Veterinary Medicine, Fujisawa Kanagawa 252-8510, Japan. kano brs.nihon-u.ac.jp

The expression of the ubiquitin (Ub) gene in dermatophytes was examined for its relation to resistance against the antifungal drug fluconazole. The nucleotide sequences and the deduced amino acid sequences of the Ub gene in Microsporum canis were proven to be 99% similar to those of the Ub gene in Trichophyton mentagrophytes. Expression of mRNA of Ub in M. canis and T. mentagrophytes was enhanced when the fungi were cultured with fluconazole. The antifungal activity of fluconazole against these dermatophytes was increased in the presence of Ub proteasome inhibitor.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11502529&dopt=Abstract fluconazole Diflucan



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[Retrospective analysis of fluconazole efficacy in Candida-colonized, non-neutropenic, surgical patients in long-term intensive care]

[Article in German]

Kappe R, Streitzig S, Bohrer H.

Institut fur Medizinische Mikrobiologie und Hygiene am Helios Klinikum Erfurt. rkappe labor-diagnostika.de

BACKGROUND AND OBJECTIVE: The early clinical diagnosis of invasive candidiasis is difficult. Fluconazole, which has been available since the early 1990s, is a relatively atoxic intravenously applicable antimycotic agent. For this reason it has been widely used - possibly too much. The aim of this study was the retrospective critical evaluation of the efficacy of systemic antifungal chemotherapy in non-neutropenic, Candida-colonized, surgical patients in long-term intensive care. PATIENTS AND METHODS: 69 patients (54 men and 15 women, aged 55.8 [range 18-87] years) of 364 patients of the anaesthesiological intensive care unit (ICU) of the University Hospital of Heidelberg in 1991 and 1992 were selected for the study. None of the 69 patients was suffering from proven invasive candidiasis according to the gold-standard criteria of positive histology, blood culture, or isolation from a sterile compartment. However, 35 of the 69 patients were systemically treated with fluconazole (on average 295 mg per day for 10.2 days intravenously). 34 patients did not receive any antifungal therapy. Retrospectively we analysed the course of the disease in both groups of patients. Furthermore, 173 serum samples of these patients were available for investigations by Western blot for anti-Candida antibodies of the immune globulin classes M and G. RESULTS: Both groups, antimycotically treated and untreated patients, had similar characteristics at base-line: age, sex, underlying disease, severity of the disease (APACHE II Score), and also mortality (approximately 20 % in both groups). Only times in the ICU and on mechanical ventilation were significantly enhanced in fluconazole treated patients (p values 0.0004 each). Before therapy, the fluconazole patients had significantly more often yeasts in primarily non-sterile compartments (chi (2) test 0.05). The yeasts were partly eradicated by fluconazole (32/54, 59.3 %). Anti-Candida antibodies significantly correlated with higher age (anti 47 kDa antigen, p = 0.02), but not with other, clinically, diagnostically or prognostically relevant parameters. CONCLUSION: Fluconazole in non-neutropenic, Candida-colonized, surgical patients in long-term ICU care neither improved the clinical course nor the mortality rate among these patients. These observations indicate that there was a trend of overestimating the clinical significance of Candida in this group of patients. Fluconazole therapy may be significantly reduced in such patients.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11514925&dopt=Abstract fluconazole Diflucan



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International surveillance of bloodstream infections due to Candida species: frequency of occurrence and in vitro susceptibilities to fluconazole, ravuconazole, and voriconazole of isolates collected from 1997 through 1999 in the SENTRY antimicrobial surveillance program.

Pfaller MA, Diekema DJ, Jones RN, Sader HS, Fluit AC, Hollis RJ, Messer SA; SENTRY Participant Group.

Department of Pathology, Iowa City, Iowa 52242, USA. michael-pfaler uiowa.edu

A surveillance program (SENTRY) of bloodstream infections (BSI) in the United States, Canada, Latin America, and Europe from 1997 through 1999 detected 1,184 episodes of candidemia in 71 medical centers (32 in the United States, 23 in Europe, 9 in Latin America, and 7 in Canada). Overall, 55% of the yeast BSIs were due to Candida albicans, followed by Candida glabrata and Candida parapsilosis (15%), Candida tropicalis (9%), and miscellaneous Candida spp. (6%). In the United States, 45% of candidemias were due to non-C. albicans species. C. glabrata (21%) was the most common non-C. albicans species in the United States, and the proportion of non-C. albicans BSIs was highest in Latin America (55%). C. albicans accounted for 60% of BSI in Canada and 58% in Europe. C. parapsilosis was the most common non-C. albicans species in Latin America (25%), Canada (16%), and Europe (17%). Isolates of C. albicans, C. parapsilosis, and C. tropicalis were all highly susceptible to fluconazole (97 to 100% at < or =8 microg/ml). Likewise, 97 to 100% of these species were inhibited by < or =1 microg/ml of ravuconazole (concentration at which 50% were inhibited [MIC(50)], 0.007 to 0.03 microg/ml) or voriconazole (MIC(50), 0.007 to 0.06 microg/ml). Both ravuconazole and voriconazole were significantly more active than fluconazole against C. glabrata (MIC(90)s of 0.5 to 1.0 microg/ml versus 16 to 32 microg/ml, respectively). A trend of increased susceptibility of C. glabrata to fluconazole was noted over the three-year period. The percentage of C. glabrata isolates susceptible to fluconazole increased from 48% in 1997 to 84% in 1999, and MIC(50)s decreased from 16 to 4 microg/ml. A similar trend was documented in both the Americas (57 to 84% susceptible) and Europe (22 to 80% susceptible). Some geographic differences in susceptibility to triazole were observed with Canadian isolates generally more susceptible than isolates from the United States and Europe. These observations suggest susceptibility patterns and trends among yeast isolates from BSI and raise additional questions that can be answered only by continued surveillance and clinical investigations of the type reported here (SENTRY Program).

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11526159&dopt=Abstract fluconazole Diflucan



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Prevalence of molecular mechanisms of resistance to azole antifungal agents in Candida albicans strains displaying high-level fluconazole resistance isolated from human immunodeficiency virus-infected patients.

Perea S, Lopez-Ribot JL, Kirkpatrick WR, McAtee RK, Santillan RA, Martinez M, Calabrese D, Sanglard D, Patterson TF.

Department of Medicine, Division of Infectious Diseases, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, USA.

Molecular mechanisms of azole resistance in Candida albicans, including alterations in the target enzyme and increased efflux of drug, have been described, but the epidemiology of the resistance mechanisms has not been established. We have investigated the molecular mechanisms of resistance to azoles in C. albicans strains displaying high-level fluconazole resistance (MICs, > or =64 microg/ml) isolated from human immunodeficiency virus (HIV)-infected patients with oropharyngeal candidiasis. The levels of expression of genes encoding lanosterol 14alpha-demethylase (ERG11) and efflux transporters (MDR1 and CDR) implicated in azole resistance were monitored in matched sets of susceptible and resistant isolates. In addition, ERG11 genes were amplified by PCR, and their nucleotide sequences were determined in order to detect point mutations with a possible effect in the affinity for azoles. The analysis confirmed the multifactorial nature of azole resistance and the prevalence of these mechanisms of resistance in C. albicans clinical isolates exhibiting frank fluconazole resistance, with a predominance of overexpression of genes encoding efflux pumps, detected in 85% of all resistant isolates, being found. Alterations in the target enzyme, including functional amino acid substitutions and overexpression of the gene that encodes the enzyme, were detected in 65 and 35% of the isolates, respectively. Overall, multiple mechanisms of resistance were combined in 75% of the isolates displaying high-level fluconazole resistance. These results may help in the development of new strategies to overcome the problem of resistance as well as new treatments for this condition.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11557454&dopt=Abstract fluconazole Diflucan



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Accumulation of fluconazole in sebum.

Zimmermann T, Laufen H, Yeates RA, Scharpf F.

Pfizer Research and Development, Illertissen, Germany.

Concentrations of fluconazole in sebum and plasma were determined in 2 parallel groups, each consisting of 8 healthy subjects. Group 1 received a 150 mg fluconazole capsule once weekly over a period of 4 weeks, Group 2 was administered 2 capsules/week, corresponding to 300 mg fluconazole/week for 4 weeks. Sampling was performed immediately before and 5 hours after dosing, and at intervals up to 2 weeks after the last dose. Fluconazole concentrations were determined by a specific and highly sensitive gas chromatographic method. Both treatments were well tolerated. Maximum fluconazole concentrations (mean +/- SD) in plasma were 3.5 +/- 1.0 microg/ml (Group 1) and 5.5 +/- 1.0 microg/ml (Group 2); maximum sebum concentrations were 11.0 +/- 8.4 microg/g (Group 1) and 48.4 +/- 37.0 microg/g (Group 2). Significant accumulation of fluconazole in sebum relative to plasma was observed. Sebum/plasma ratios ranged from 1.6 to 6.5 (Group 1) and from 4.3 to 27.9 (Group 2), with median ratios of 2.4 and 9.1, respectively. The overall accumulation factor was 7. The findings may be of particular relevance for the treatment of dermal mycoses involving the sebaceous glands, especially those associated with hair, such as tinea capitis.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11563685&dopt=Abstract fluconazole Diflucan



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Breakthrough fungaemia in neonates and infants caused by Candida albicans and Candida parapsilosis susceptible to fluconazole in vitro.

Krcmery V, Huttova M, Mateicka F, Laho L, Jurga L, Ondrusova A, Tarekova Z, Kralinsky K, Hanzen J, Liskova A, Mrazova M, Sabo A, Pisarcikova M, Kovacicova G, Chovancova D, Szovenyiova Z.

Department of Paediatrics, University of Trnava, School of Public Health, Bratislava 812 50, Slovak Republic. krcmery spamba.sk

Breakthrough fungaemias due to Candida albicans and Candida parapsilosis appearing during fluconazole therapy in neonates and infants were assessed for risk factors and outcome. Forty fungaemias occurred during therapy with fluconazole within a 12 year national survey and were compared with 161 cases of non-breakthrough paediatric fungaemias. The agar disc diffusion test method was used for antifungal susceptibility testing and the Vitek system for species identification. Univariate and multivariate analysis for risk factors for breakthrough fungaemia were carried out. All the fungaemias were a result of strains susceptible to fluconazole at 0.25-4 mg/L in vitro [C. albicans (85%) and C. parapsilosis (15%)]. The mean number of positive blood cultures per episode was 2.2. Sixteen children had 'early' breakthrough fungaemias (within 4-5 days) and 24 fungaemias appeared on day 6 and later. Mean fluconazole MICs in the 'early' group were 1.2, and 2.8 mg/L in the 'late' group (P < 0.03, t-test). However, no difference was observed in the average dose of fluconazole used in the two groups. Neonatal age, total parenteral nutrition, very low birth weight, before surgery, central or umbilical venous catheterization and artificial ventilation were all significantly related to breakthrough fungaemia in univariate analysis but only central or umbilical venous catheterization were significant in multivariate analysis. The outcome of breakthrough fungaemia was better overall and attributable mortalities in non-breakthrough fungaemia was significantly higher in comparison with breakthrough fungaemia.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11581231&dopt=Abstract fluconazole Diflucan