Effects Of Azole Antifungal Agents Research Articles

Physiologically based pharmacokinetic modeling to predict the clinical effect of azole antifungal agents as CYP3A inhibitors on azelnidipine pharmacokinetics

In this study, a physiologically based pharmacokinetic (PBPK) model of the cytochrome P450 3A (CYP3A) substrate azelnidipine was developed using in vitro and clinical data to predict the effects of azole antifungals on azelnidipine pharmacokinetics. Modeling and simulations were conducted using the Simcyp™ PBPK simulator. The azelnidipine model consisted of a full PBPK model and a first-order absorption model. CYP3A was assumed as the only azelnidipine elimination route, and CYP3A clearance was optimized using the pharmacokinetic profile of single-dose 5-mg azelnidipine in healthy participants. The model reproduced the results of a clinical drug–drug interaction study and met validation criteria. PBPK model simulations using azole antifungals (itraconazole, voriconazole, posaconazole, fluconazole, fosfluconazole) and azelnidipine or midazolam (CYP3A index substrate) were performed. Increases in the simulated area under the plasma concentration–time curve from time zero extrapolated to infinity with inhibitors were comparable between azelnidipine (range, 2.11–6.47) and midazolam (range, 2.26–9.22), demonstrating that azelnidipine is a sensitive CYP3A substrate. Increased azelnidipine plasma concentrations are expected when co-administered with azole antifungals, potentially affecting azelnidipine safety. These findings support the avoidance of azole antifungals in patients taking azelnidipine and demonstrate the utility of PBPK modeling to inform appropriate drug use.

Evaluating the Effect of Azole Antifungal Agents on the Stress Response and Nanomechanical Surface Properties of Ochrobactrum anthropi Aspcl2.2.

Azole antifungal molecules are broadly used as active ingredients in various products, such as pharmaceuticals and pesticides. This promotes their release into the natural environment. The detailed mechanism of their influence on the biotic components of natural ecosystems remains unexplored. Our research aimed to examine the response of Ochrobactrum anthropi AspCl2.2 to the presence of four azole antifungal agents (clotrimazole, fluconazole, climbazole, epoxiconazole). The experiments performed include analysis of the cell metabolic activity, cell membrane permeability, total glutathione level and activity of glutathione S-transferases. These studies allowed for the evaluation of the cells’ oxidative stress response to the presence of azole antifungals. Moreover, changes in the nanomechanical surface properties, including adhesive and elastic features of the cells, were investigated using atomic force microscopy (AFM) and spectrophotometric methods. The results indicate that the azoles promote bacterial oxidative stress. The strongest differences were noted for the cells cultivated with fluconazole. The least toxic effect has been attributed to climbazole. AFM observations unraveled molecular details of bacterial cell texture, structure and surface nanomechanical properties. Antifungals promote the nanoscale modification of the bacterial cell wall. The results presented provided a significant insight into the strategies used by environmental bacterial cells to survive exposures to toxic azole antifungal agents.

Comparison of the inhibitory effect of ketoconazole, voriconazole, fluconazole, and itraconazole on the pharmacokinetics of bosentan and its corresponding active metabolite hydroxy bosentan in rats

1. This study aimed to investigate the inhibitory effect of azole antifungal agents, including ketoconazole, voriconazole, fluconazole, and itraconazole, on the pharmacokinetics of bosentan (BOS) and its active metabolite hydroxy bosentan (OHBOS) in Sprague–Dawley (SD) rats.2. A total of 25 healthy male SD rats were divided into five groups and treated with various azole antifungal agents by gavage, followed by a single dose of BOS after 30 min.3. The study found that ketoconazole led to a significant increase (5.1-fold) in the AUC(0-t) of BOS, associated with a 5.8-fold elevation in the Cmax, which was greater than that for fluconazole (2.6- and 2.9-fold) and voriconazole (1.1- and 1.7-fold). Accordingly, the Vz/F and CLz/F of BOS reduced by 89.2% and 83.7%, respectively, on administering ketoconazole concomitantly. However, fluconazole caused a decrease in Vz/F and CLz/F by 77.4% and 72.2%, respectively, compared with voriconazole that exhibited a decrease in CLz/F by 51.7% with a negligible change in Vz/F. Also, obvious differences were observed in the pharmacokinetic parameters of OHBOS between the control and treated groups.4. Collectively, treatment with ketoconazole resulted in a prominent inhibitory effect on the metabolism of BOS, followed by treatment with fluconazole, voriconazole, and itraconazole. Therefore, these details of animal studies may help draw more attention to the safety of BOS while combining it with ketoconazole, voriconazole, fluconazole, or itraconazole clinically.

Substrate Specificity of Human Cytochrome P450 (CYP) 2C Subfamily and Effect of Azole Antifungal Agents on CYP2C8.

The metabolic activities of aminopyrine N-demethylation and tolbutamide methylhydroxylation by the human hepatic cytochrome P450 (P450 or CYP) 2C subfamily were compared and the effects of azole antifungal agent on the drug-metabolizing activity of CYP2C8 were investigated. Aminopyrine N-demethylation and tolbutamide methylhydroxylation by CYP2C8, CYP2C9, and CYP2C19 were determined by the previous reported methods. The effects of five azole antifungal agents, fluconazole, itraconazole, ketoconazole, miconazole, and voriconazole, on the aminopyrine N-demethylation activity by CYP2C8 were investigated. With regard to aminopyrine N-demethylation, CYP2C19 had the lowest Michaelis constant (Km) and CYP2C8 had the highest maximal velocity (Vmax) among the CYP2C subfamily members. The Vmax/Km values for CYP2C8 were the highest, followed by CYP2C19. For tolbutamide methylhydroxylation, the Km and Vmax for CYP2C19 were three and six times higher than the corresponding values for CYP2C9, and the Vmax/Km value for CYP2C19 was twice that for CYP2C9, whereas hydroxylated tolbutamide formed by CYP2C8 was not detected. Fluconazole, itraconazole, and voriconazole at a concentration of 2 or 10 µM neither inhibited nor stimulated CYP2C8-mediated aminopyrine N-demethylation activity at substrate concentrations around the Km (5 mM). However, ketoconazole and miconazole noncompetitively inhibited CYP2C8-mediated aminopyrine N-demethylation with the inhibitory constant values of 1.98 and 0.86 µM, respectively. These results suggest that ketoconazole and miconazole might inhibit CYP2C8 clinically.This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Comparison of the effects of azole antifungal agents on the anticoagulant activity of warfarin.

The package insert of the antithrombotic agent warfarin warns users of its interaction with azole antifungals. However, information on the frequency or degree of these interactions is limited. In particular, the time to onset of azole-mediated prothrombin time prolongation, expressed as the international normalized ratio (INR), is poorly characterized. Therefore, we retrospectively examined the INR in 29 patients administered warfarin with fluconazole (FLCZ), voriconazole (VRCZ), or itraconazole (ITCZ). INRs in 18 patients taking FLCZ and in 5 patients taking VRCZ significantly increased from 1.40 to 2.94 and from 1.95 to 2.89, respectively. The warfarin sensitivity index (WSI), calculated as INR/daily warfarin dose, also significantly increased from 1.06 to 1.89 with FLCZ and showed an upward trend from 1.13 to 2.23 with VRCZ. ITCZ had no influence on the INR or WSI in 6 patients. The INRs observed when warfarin was coadministered with azoles (Y) correlated significantly with those observed in the absence of azoles (X): FLCZ, Y=4.94X-3.96, r(2)=0.80; VRCZ, Y=2.13X-1.27, r(2)=0.93. Moreover, in all 8 patients with closely monitored INRs, the WSI increased within 1 week of FLCZ or VRCZ coadministration. In conclusion, FLCZ and VRCZ augmented the anticoagulant activity of warfarin. The INR should be closely monitored within 1 week of initiating FLCZ or VRCZ coadministration with warfarin, especially in patients with high INRs.

Blockade of K<sup>+</sup> and Ca<sup>2+</sup> Channels by Azole Antifungal Agents in Neonatal Rat Ventricular Myocytes

Some azole antifungal agents induce long QT syndrome and arrhythmias. Although composite functions of ion channels in cardiomyocytes contribute to the shaping of action potentials, information on the effects of azole antifungal agents on ion currents, except human-ether-a-go-go-related gene (HERG) K+ currents, is largely lacking. Using the whole cell patch-clamp technique, we investigated the effects of four azole agents (miconazole, ketoconazole, fluconazole, and itraconazole) on inward rectifying K+ currents (IKir), voltage-gated L-type Ca2+ currents (ICaL), and delayed rectifier K+ currents (IKdr) in rat neonate ventricular myocytes. Strikingly, miconazole and ketoconazole strongly inhibited IKir, IKdr, and ICaL at clinically relevant concentrations. The IC50 values of miconazole for IKdr, IKir, and ICaL inhibition were 2.5, 10.4, and 3.0 µM, respectively. The IC50 values of ketoconazole for IKdr, IKir and ICaL inhibition were 3.2, 20.8, and 3.5 µM, respectively. Fluconazole and itraconazole had relatively little effect on ion currents. These findings indicate that miconazole and ketoconazole are multiple ion channel inhibitors in cardiomyocytes. We suggest that it is necessary to consider this inhibition of ion channels by azole agents when assessing cardiovascular side effects.

Comparison of Kinetic Parameters for Drug Oxidation Rates and Substrate Inhibition Potential Mediated by Cytochrome P450 3A4 and 3A5

Cytochrome P450 (P450 or CYP) 3A is one of the most important P450 subfamilies in terms of its broad substrate specificity and relatively high abundance in humans. The substrate specificities of CYP3A4 and CYP3A5 are generally overlapped, but sometimes could differ from each other. It is still important to understand drug interactions more precisely in individual subjects. However, there are few review articles regarding comparative drug oxidation rates catalyzed by CYP3A4 and CYP3A5 and/or substrate inhibition potential towards CYP3A4 and CYP3A5. In this article, we summarize 1) Michaelis-Menten constants (Km), maximal velocities (Vmax), and intrinsic clearance (Vmax/Km) values for 63 substrates (94 reactions) mediated by CYP3A4 and/or CYP3A5, 2) inhibition constants (Ki) and 50% inhibitory concentrations (IC50) of 18 substrates, and 3) maximum inactivation rate constants (kinact) of 14 inhibitors from the literature. The relative contribution of polymorphic CYP3A5 compared with inducible CYP3A4 varies with the substrates and the reaction positions of the substrates. Inhibitory effects of azole antifungal agents and macrolide antibiotics, with low Ki and/or IC50 values for CYP3A4, are likely to be determinant factors for predominant drug interactions in humans, although Asian subjects with relatively high frequency of genetic CYP3A5 expressers should be carefully treated with CYP3A substrates. The collective findings in our present survey provide fundamental and useful information for drug oxidations catalyzed by CYP3A4 and CYP3A5, in spite of some contradictive kinetic parameters for the same reactions reported from many laboratories in different conditions. To understand causal factor(s) and mechanism(s) for such different reports summarized here is still one of the hot research topics to be solved in current drug metabolism.

Azoles for allergic bronchopulmonary aspergillosis associated with asthma.

Allergic bronchopulmonary aspergillosis is hypersensitivity to the fungus Aspergillus fumigatus that complicates patients with asthma and cystic fibrosis. The mainstay of treatment for allergic bronchopulmonary aspergillosis remains oral corticosteroids, though this does not completely prevent exacerbations and may not prevent the decline in lung function. The purpose of this review was to determine the efficacy of azoles in the treatment of allergic bronchopulmonary aspergillosis. We searched the Cochrane Airways Group Asthma trials register using the terms: (allergic bronchopulmonary aspergillosis OR aspergillosis OR allergic pulmonary aspergillosis OR allergic fungal and disease OR allergic mycotic and disease) AND (azole OR triazole OR itraconazole OR ketoconazole). Date of last search January 2003. All controlled trials that assessed the effect of azole antifungal agents compared to placebo or other standard therapy for allergic bronchopulmonary aspergillosis were reviewed. Patients with cystic fibrosis were not included. Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. Adverse effects information was collected from the trials. Twelve trials were identified, but only three were prospective, randomised and controlled. A total of 94 participants were included. One demonstrated a reduction in immunological markers of disease activity and symptom scores using ketoconazole 400 mg daily for 12 months. There was no significant improvement in lung function. The other two examined the use of itraconazole for 16 weeks. In one there was a reduction in sputum eosinophils by 35% compared to 19% with placebo (p < 0.01). In the same trial, the number of exacerbations requiring oral corticosteroids was 0.4 per patient with itraconazole compared with 1.3 per patient with placebo (p < 0.03). Meta-analysis of data from both trials showed that itraconazole treated patients were more likely to have decline in serum IgE over 25% or more (Peto OR 3.30; 95% confidence intervals 1.30 to 8.15). Itraconazole modifies the immunologic activation associated with allergic bronchopulmonary aspergillosis and improves clinical outcome, at least over the period of 16 weeks. Adrenal suppression with inhaled corticosteroids and itraconazole is a potential concern.

Azoles for allergic bronchopulmonary aspergillosis.

Allergic Broncho-pulmonary Aspergillosis (ABPA) is hypersensitivity to the fungus Aspergillus Fumigatus that complicates patients with asthma and cystic fibrosis. The condition usually results in an increase in symptoms, a greater reliance on corticosteroids to control the disease process and may lead to a progressive decline in lung function. The mainstay of treatment for ABPA remains oral corticosteroids, though this does not completely prevent exacerbations and may not prevent the decline in lung function. The purpose of this review is to determine the efficacy of azoles in the treatment of ABPA SEARCH STRATEGY: An initial search was carried out using the Cochrane Airways Group Asthma RCT register. The register was searched using the following terms: (asthma or wheeze) and (allergic bronchopulmonary aspergillosis or aspergillosis or allergic pulmonary aspergillosis or allergic fungal and disease or allergic mycotic and disease) and (azole or triazole or itraconazole or ketoconazole). All controlled trials that assessed the effect of azole antifungal agents compared to placebo or other standard, for any duration or dose regimen in subjects with ABPA of any age or severity were reviewed. Studies in languages other than English were included. All identified trials were independently reviewed by both reviewers & all data collected. Trial quality was scored by the Cochrane assessment of allocation concealment & the Jadad scale of methodological quality. A total of 11 trials were identified concerning the use of azoles in ABPA. Only two prospective controlled trials were identified. The first trial examined the use of Ketoconazole 400 mg daily for 12 months and demonstrated a reduction in immunological markers of disease activity and symptom scores, there was no significant improvement in lung function. The other trial examined the use of itraconazole for 16 weeks. This demonstrated a reduction in corticosteroid usage, an improvement in immunological markers, an improvement in pulmonary function and exercise tolerance. This study was only available as an abstract and limited details were available. There is insufficient information available to recommend the use of azole anti-fungal agents in the routine treatment of patients with ABPA.

Inhibitory effect of azole antifungal agents on the glucuronidation of lorazepam using rabbit liver microsomes in vitro.

Azole antifungal agents (azoles) have inhibitory effects on the cytochrome P450. However, the effect of azoles on conjugative metabolism has not been given much attention. Lorazepam (LZP), a benzodiazepine sedative agent, is known to be metabolized by uridine 5'-diphosphate (UDP)-glucuronyltransferase. Herein we report investigation of the effect of azoles on the enzyme-kinetics of glucuronidation of lorazepam using rabbit liver microsomes in vitro. The Km and Vmax for LZP glucuronidation were determined to be 0.26+/-0.08 mM and 1.25+/-0.21 nmol/min/mg protein, respectively, when evaluated in the presence of a detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS) (0.8 mg/mg protein). Azoles fluconazole, miconazole, and ketoconazole competitively inhibited the glucuronidation of LZP, with Ki values of 7.17+/-4.78 mM, 0.17+/-0.08 mM, and 0.092+/-0.026 mM, respectively. These results are comparable to the previously reported Ki values of azoles with zidovudine (AZT) glucuronidation (1.4, 0.18, and 0.08 mM for fluconazole, miconazole, and ketoconazole, respectively) [Sampol et al., Br. J. Clin. Pharmacol., 40, 83-86, 1995]. Therefore, in order to avoid possible side effects of LZP, the concomitant administration of LZP and azoles should be carefully evaluated.

Effects of azole antifungal agents on ionomycin-induced changes in intracellular calcium concentration in Trichophyton rubrum

Recent studies suggest that the antifungal agents itraconazole, bifonazole, and ketoconazole affect calcium-mediated signal transduction in Trichophyton rubrum. We have now examined the effects of azole-antifungal agents on cell membrane function in T. rubrum, by analysing the effects of itraconazole, bifonazole, ketoconazole, and lanoconazole on ionomycin-induced changes in intracellular calcium concentration ([Ca2+]1). Addition of 1 μM ionomycin to the culture medium produced a persistent increase in [Ca2+]1. While treatment with 1·5–15 nM of lanoconazole or bifonazole for 24 h did not affect this ionomycin-induced increase in [Ca2+]1, 30 nM of these agents resulted in a transient increase in [Ca2+]1 rather than the usual sustained increase in [Ca2+]1. This transient ionomycin-induced increase in [Ca2+]1 was also observed after treatment with only 1·5 and 3 nM of ketoconazole or itraconazole. Incubation in the presence of lanoconazole or bifonazole at ≥150 nM, and ketoconazole or itraconazole at ≥15 nM inhibited both the persistent and transient ionomycin-induced increase in [Ca2+]1. On the basis of these findings, it is suggested that azole antifungal agents disturb membrane function in T. rubrum, and that one manifestation of this effect is the disruption of the ionomycin-induced increase in [Ca2+]1. We report that the ionomycin-induced increase in [Ca2+1, is more sensitive to low concentrations of ketoconazole and itraconazole compared to bifonazole and lanoconazole.

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093 Different effects of azole-antifungal agents on the intracellular calcium response to ionomycin in [formula omitted

Different effects of azole-antifungal agents on the regulation of intracellular calcium concentration of Trichophyton rubrum

Prior studies have indicated that intracellular calcium concentration ([Ca 2+] i) is involved in fungal cell growth. However, it has not been known whether antifungal drugs affect signal transduction via calcium in fungal cells. In this context, we examined the effects of antifungal drugs, itraconazole, bifonazole and ketoconazole, on [Ca +] i in Trichophyton rubrum. Itraconazole (1–5 ng/ml) induced a rapid and transient [Ca 2+] i increase, peaking at 15–20 s in hyphal cells of T. rubrum, but not in spores. The slow descending phase of the [Ca 2+] i increase induced by itraconazole was depleted by chelating extracellular calcium with ethylene glycol bis(β-aminoethyl ether)- N, N,N′,N′-tetraacetic acid (EGTA), suggesting that the increase in [Ca 2+] i is biphasic: Ca 2+ mobilization from the internal pool and influx from the outside of the cell. At 10 ng/ml and 100 ng/ml, however, itraconazole induced an explosive and sustained calcium increase in both spores and hyphae. At less than 1 ng/ml, no [Ca 2+] i increase was caused in both hyphae and spores. On the other hand, although some hyphal cells showed a transient [Ca 2+] i increase, most of the cells did not show any changes of [Ca 2+] i after the addition of ketoconazole at 10 ng/ml. Both spores and hyphal cells incubated with 100 ng/ml of bifonazole or ketoconazole showed a gradual increase of intracellular calcium concentration until 5 min, when the measurement was ceased. These findings suggest that signal transduction via calcium might be involved in some biological effects of itraconazole on T. rubrum, and that bifonazole and ketoconazole could differently affect [Ca 2+] i in T. rubrum from itraconazole. In addition, the determination of [Ca 2+] i changes induced by antifungal agents may contribute to clarification of the biological effects on fungal membranes.