Antifungal agents. Part II. The azoles

Diversity of Parengyodontium spp. strains isolated from the cultural heritage environment: Phylogenetic diversity, phenotypical diversity, and occurrence

Parengyodontium album is a fungal species that frequently occurs in the cultural heritage environment. Although three subclades were initially described in the species, no study has sought to determine the occurrence of each subclade in the cultural heritage context. These subclades are easily distinguishable phylogenetically, but their morphological identification is more difficult. Eighteen strains isolated from different cultural sites and initially identified as P. album were studied phylogenetically, morphologically, and in terms of their susceptibility to econazole nitrate 0.2%, an antifungal product used as preservation treatment in cultural heritage domain. The phylogenetic study revealed that all studied strains belonged to P. album subclade 1 or P. torokii (P. album subclade 3) and none belonged to P. album subclade 2. The morphological study revealed the best characteristics to differentiate the three subclades/species, namely, the ability of the strains to grow at 32 C and 35 C on potato dextrose agar (PDA) medium and the shape of conidia. Finally, the strains displayed variable susceptibilities to econazole nitrate, with no apparent link to any particular subclade/species.

Identifying novel drugs with new modes of action for neglected tropical fungal skin diseases (fungal skinNTDs) using an Open Source Drug discovery approach

INTRODUCTION

The three fungal skin neglected tropical diseases (NTD) mycetoma, chromoblastomycosis and sporotrichosis currently lack prioritization and support to establish drug discovery programs in search for novel treatment options. This has made the efforts to identify novel drugs for these skinNTDs fragmented.

AREAS COVERED

To help escalate the discovery of novel drugs to treat these fungal skinNTDs, the authors have prepared an overview of the compounds with activity against fungal skinNTDs by analyzing data from individual drug discovery studies including those performed on the Medicines for Malaria Venture (MMV) open access boxes.

EXPERT OPINION

The authors were unable to identify studies in which causative agents of all three skinNTDs were included, indicating that an integrated approach is currently lacking. From the currently available data, the azoles and iodoquinol were the only compounds with activity against causative agents from the three different fungal skinNTDs. Fungal melanin inhibition enhanced the activity of antifungal agents. For mycetoma, the fenarimols, aminothiazoles and benzimidazole carbamates are currently being investigated in the MycetOS initiative. To come to a more integrated approach to identify drugs active against all three fungal skinNTDs, compounds made in the MycetOS initiative could also be explored for chromoblastomycosis and sporotrichosis.

Antimicrobial activity of denture adhesive associated with Equisetum giganteum- and Punica granatum-enriched fractions against Candida albicans biofilms on acrylic resin surfaces

Candida biofilms adhere to the internal surface of removable dentures, which is an etiological factor in the pathogenesis of denture stomatitis (DS). Adhesive materials are used at the base of maxillary complete dentures to improve their retention and chewing qualities. This article reports the antimicrobial activity of the enriched fractions of Equisetum giganteum and Punica granatum incorporated into a denture adhesive against C. albicans biofilm. The biofilms were induced on the surface of heat-cured acrylic resin specimens that were previously treated with a mixture of adhesive/herb extracts. The antimicrobial activity was evaluated by CFU counts, XTT reduction, and SEM and CLSM analysis. Both herb extracts amplified the anti-biofilm action of the adhesive on the acrylic resin by up to 12 h. Therefore, when these extracts were combined with COREGA®, they played a collaborative and innovative role in biofilm control and can be considered alternatives for temporary use in the treatment and/or prevention of DS.

Hepatotoxicity induced by antifungal drugs itraconazole and fluconazole in rats: a comparative in vivo study

Itraconazole and fluconazole are oral antifungal drugs, which have a wide spectrum antifungal activity and better efficacy than the older drugs. However, both drugs have been associated with hepatotoxicity in susceptible patients. The mechanism of antifungal drug-induced hepatotoxicity is largely unknown. Therefore, the aim of this present study was to investigate and compare the hepatotoxicity induced by these drugs in vivo. Rats were treated intraperitoneally with itraconazole or fluconazole either single (0, 10, l00 and 200 mg/kg) or subchronic (0, 10, 50 and loo mg/kg per day for 14 days) doses. Plasma and liver samples were taken at the end of the study. A statistically significant and dose dependent increase of plasma alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activities were detected in the subchronic itraconazole-treated group. In addition, dose-dependent hepatocellular necrosis, degeneration of periacinar and mizonal hepatocytes, bile duct hyperplasia and biliary cirrhosis and giant cell granuloma were observed histologically in the same group. Interestingly, fluconazole treated rats had no significant increase in transaminases for both single and subchronic groups. In the subchronic fluconazole treated rats, only mild degenerative changes of centrilobular hepatocytes were observed. These results demonstrated that itraconazole was a more potent hepatotoxicant than fluconazole in vivo in rats.

Fluconazole and acetazolamide in the treatment of ectopic Cushing's syndrome with severe metabolic alkalosis

Cushing's syndrome (CS) due to ectopic ACTH production accounts for about 10% of all types of CS and is frequently associated with metabolic alkalosis. Treatment of CS involves surgical resection and/or medical therapy to control hypercortisolism. We present the case of an 80-year-old woman affected by CS due to an unknown cause. The patient had severe metabolic alkalosis with refractory hypokalemia. To treat the underlying CS, fluconazole was initiated due to unavailability of ketoconazole. In spite of markedly decreasing cortisol levels, metabolic alkalosis persisted. Treatment of metabolic alkalosis with acetazolamide was thus initiated and pH levels successfully lowered. This case report shows that hypercortisolism can be effectively treated with fluconazole in cases where ketoconazole is unavailable or not tolerated and that persistent severe metabolic alkalosis caused by glucocorticoid excess can be safely and successfully treated with acetazolamide.

LEARNING POINTS

Hypercortisolism can be effectively treated with fluconazole where ketoconazole is unavailable or not tolerated.Glucocorticoid excess can cause severe metabolic alkalosis.Persistent severe metabolic alkalosis can be safely and successfully treated with acetazolamide.

Recent advances in antifungal pharmacotherapy for invasive fungal infections

Invasive fungal infections carry significant morbidity and mortality. Candida species have become one of the most frequent causes of bloodstream infections, and infections caused by molds such as Aspergillus are becoming more frequent in immunocompromised patients. As this population grows, more invasive fungal infections can be anticipated. In the past, treatment options have been limited for many of these infections due to toxicity and efficacy concerns with the available antifungals. Fortunately, the past few years have brought exciting developments in antifungal pharmacotherapy. Lipid-based formulations of amphotericin B were introduced in the 1990s to attenuate adverse effects caused by amphotericin B deoxycholate (Fungizone, Bristol-Myers Squibb). Most recently, the echinocandins have been added to our antifungal regimen with the introduction of caspofungin (Cancidas, Merck and Co.) and voriconazole (Vfend, Pfizer), a new triazole, has come to market. The introduction of the echinocandins has invigorated the discussion about combination antifungal therapy. Evidence-based studies using these new agents are accumulating, and they are assuming important roles in the pharmacotherapy of invasive fungal infections in seriously ill and complex patients.

Iatrogenic neurology

Iatrogenic disease is one of the most frequent causes of hospital admissions and constitutes a growing public health problem. The most common type of iatrogenic neurologic disease is pharmacologic, and the central and peripheral nervous systems are particularly vulnerable. Despite this, iatrogenic disease is generally overlooked as a differential diagnosis among neurologic patients. The clinical picture of pharmacologically mediated iatrogenic neurologic disease can range from mild to fatal. Common and uncommon forms of drug toxicity are comprehensively addressed in this chapter. While the majority of neurologic adverse effects are listed and referenced in the tables, the most relevant issues are further discussed in the text.

Cutaneous Mycoses among Rice Farmers in Anambra State, Nigeria

Rice grain is one of the world's most important food crops, and its cultivation is a major occupation in Anambra State, Nigeria. These rice farmers are exposed to various agents that predispose them to cutaneous mycoses. The aim of this work was to screen rice farmers for lesions suggestive of cutaneous mycoses and to isolate and identify fungal agents associated with the infection. This survey was carried out between November 2009 and June 2011 in Anambra State, Nigeria. Clinical samples collected from 201 farmers with lesions suggestive of cutaneous mycoses were processed and the organisms identified. Questionnaires were used to obtain other necessary data and were statistically analyzed. Of the 2,580 rice farmers screened, 201 (7.79%) showed positive lesions. Organisms recovered included Microsporum audouinii, Microsporum ferrugineum, Trichophyton megnini, Trichophyton tonsurans, Trichophyton rubrum, Aspergillus terrus, Aspergillus candidus, Aspergillus scleriotorum, Aspergillus niger, Aspergillus flavus, Scopulariopsis sp., Chrysosporium sp., Eupenicillium javanicum, Fusarium sp., Penicillium aculeatum, and Penicillium pinophilum. At the end of this work, onychomycosis was observed to be the most prevalent with nondermatophyte molds now becoming very important agents of cutaneous mycoses among rice farmer.

Fluconazole inhibits human adrenocortical steroidogenesis in vitro

The antifungal agent ketoconazole is often used to suppress cortisol production in patients with Cushing's syndrome (CS). However, ketoconazole has serious side effects and is hepatotoxic. Here, the in vitro effects of ketoconazole and fluconazole, which might be less toxic, on human adrenocortical steroidogenesis were compared. The effects on steroidogenesis were examined in primary cultures of nine human adrenocortical tissues and two human adrenocortical carcinoma cell lines. Moreover, the effects on mRNA expression levels of steroidogenic enzymes and cell growth were assessed. Ketoconazole significantly inhibited 11-deoxycortisol (H295R cells; maximum inhibition 99%; EC(50) 0.73 μM) and cortisol production (HAC15 cells; 81%; EC(50) 0.26 μM and primary cultures (mean EC(50) 0.75 μM)). In cultures of normal adrenal cells, ketoconazole increased pregnenolone, progesterone, and deoxycorticosterone levels, while concentrations of 17-hydroxypregnenolone, 17-hydroxyprogesterone, 11-deoxycortisol, DHEA, and androstenedione decreased. Fluconazole also inhibited 11-deoxycortisol production in H295R cells (47%; only at 1 mM) and cortisol production in HAC15 cells (maximum inhibition 55%; EC(50) 35 μM) and primary cultures (mean EC(50) 67.7 μM). In the cultures of normal adrenals, fluconazole suppressed corticosterone, 17-hydroxypregnenolone, and androstenedione levels, whereas concentrations of progesterone, deoxycorticosterone, and 11-deoxycortisol increased. Fluconazole (1 mM) slightly increased STAR mRNA expression in both cell lines. Neither compound affected mRNA levels of other steroidogenic enzymes or cell number. In conclusion, by inhibiting 11β-hydroxylase and 17-hydroxylase activity, pharmacological concentrations of fluconazole dose dependently inhibit cortisol production in human adrenocortical cells in vitro. Although fluconazole seems less potent than ketoconazole, it might become an alternative for ketoconazole to control hypercortisolism in CS. Furthermore, patients receiving fluconazole because of mycosis might be at risk for developing adrenocortical insufficiency.

Antifungal resistance and new strategies to control fungal infections

Despite improvement of antifungal therapies over the last 30 years, the phenomenon of antifungal resistance is still of major concern in clinical practice. In the last 10 years the molecular mechanisms underlying this phenomenon were extensively unraveled. In this paper, after a brief overview of currently available antifungals, molecular mechanisms of antifungal resistance will be detailed. It appears that major mechanisms of resistance are essential due to the deregulation of antifungal resistance effector genes. This deregulation is a consequence of point mutations occurring in transcriptional regulators of these effector genes. Resistance can also follow the emergence of point mutations directly in the genes coding antifungal targets. In addition we further describe new strategies currently undertaken to discover alternative therapy targets and antifungals. Identification of new antifungals is essentially achieved by the screening of natural or synthetic chemical compound collections. Discovery of new putative antifungal targets is performed through genome-wide approaches for a better understanding of the human pathogenic fungi biology.

Terbinafine pharmacokinetics after single dose oral administration in the dog

Terbinafine is an allylamine antifungal prescribed for the treatment of mycoses in humans. It is increasingly being used in veterinary patients. The purpose of this study was to evaluate the pharmacokinetic properties of terbinafine in dogs after a single oral dose. Ten healthy adult dogs were included in the study. A single dose of terbinafine (30-35 mg/kg) was administered orally, and blood samples were periodically collected over a 24 h period during which dogs were monitored for adverse effects. Two of 10 dogs developed transient ocular changes. A high-performance liquid chromatography assay was developed and used to determine plasma terbinafine concentrations. Pharmacokinetic analysis was performed using PK Solutions(®) computer software. Area under the curve (AUC) from time 0 to 24 h was 15.4 μg·h/mL (range 5-27), maximal plasma concentration (C(max) ) was 3.5 μg/mL (range 3-4.9 μg/mL) and time to C(max) (T(max) ) was 3.6 h (range 2-6 h). The time above minimal inhibitory concentration (T > MIC) as well as AUC/MIC was calculated for important invasive fungal pathogens and dermatophytes. The T > MIC was 17-18 h for Blastomyces dermatitidis, Histoplasma capsulatum and dermatophytes (Microsporum spp. and Trichophyton mentagrophytes), while the MIC for Sporothrix schenckii and Coccidioides immitis was exceeded for 9.5-11 h. The AUC/MIC values ranged from 9 to 13 μg h/mL for these fungi. Our results provide evidence supporting the use of terbinafine as an oral therapeutic agent for treating systemic and subcutaneous mycoses in dogs.

Effects of cytochrome p450 inhibitors on itraconazole and fluconazole induced cytotoxicity in hepatocytes

Itraconazole and fluconazole have been reported to induce hepatotoxicity in patients. The present study was designed to investigate the role of cytochrome P450 inhibitors, SKF 525A, and curcumin pretreatment on the cytotoxicity of antifungal drugs fluconazole and itraconazole. For 3 consecutive days, female rats were administered daily SKF 525A or curcumin (5 and 25 mg/kg). Control rats received an equivalent amount of dosed vehicle. The animals were anaesthetized 24 hours after receiving the last dose for liver perfusion. Hepatocytes were then exposed to various concentrations of antifungal drugs. In vitro incubation of hepatocytes with itraconazole revealed significantly lower viability when compared to fluconazole as assessed by lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase activities. The cytotoxicity of itraconazole was enhanced when incubated with hepatocytes pretreated with SKF 525A. SKF 525A had no effects on the cytotoxicity of fluconazole. Curcumin failed to either increase or decrease the cytotoxicity of both antifungal drugs. ATP levels also showed significant decrease in both itraconazole and fluconazole incubated hepatocytes. However, SKF 525A pretreated hepatocytes had significantly lower ATP levels after itraconazole incubations. Collectively, these results confirm the involvement of cytochrome P450 in the cytoprotection in itraconazole induced hepatocyte toxicity. Differences of the effects of SKF 525A on the cytotoxicity induced by itraconazole and fluconazole may be due to the differences on the metabolism of each antifungal drug in vivo.

Antimicrobial agents for surgical infections

Antimicrobial drugs are useful for the empiric and definitive treatment of infections in surgical patients. They are also important agents for perioperative antimicrobial prophylaxis. The proper selection and use of these drugs is a critical skill for surgeons. Although these agents have many beneficial effects, they also possess occasional adverse effects and should not be used indiscriminately.

Fluconazole-induced Recurrent Ventricular Fibrillation Leading to Multiple Cardiac Arrests

This case report describes the successful management of a patient with diabetic ketoacidosis, who developed torsades de pointes leading to nine cardiac arrests secondary to intravenous fluconazole administration on a background of hypokalaemia and hypocalcaemia.

Histopathological effect of ketoconazole on rat placenta

In order to investigate the morphological effects of ketoconazole on hypertrophied placentas, we examined the sequential histopathological changes in the placenta from rats exposed to ketoconazole. Ketoconazole was administered orally at 0 and 25 mg/kg/day during gestation days (GDs) 12 to 14, and the placentas were sampled on GDs 15, 17 and 21. All dams showed neither effect on body weight nor any abnormal clinical signs during the experimental period. In the treated group, the placentas appeared more hypertrophic with increases in the weight, diameter and thickness on GD 21. Histopathologically, increased thickness was noted in the labyrinth zone and basal zone on GDs 17 and 21, while on GD 15 the change had been already evident in the former zone. In the labyrinth zone, the mitotic figures of the trophoblasts were significantly elevated on GD 15. A multiple cystic dilatation of maternal sinusoids was observed in some placentas on GDs 15, 17 and 21. In the basal zone, an increase in spongiotrophoblasts and clusters of glycogen cells were detected on GDs 17 and 21. In the decidua basalis, there were no significant changes in either histology or thickness between the control and treated group during GDs 15 to 21. In conclusion, ketoconazole increased the population of composed cells in the labyrinth and basal zone, leading to placental hypertrophy in pregnant rats.

Biodegradable implantable fluconazole delivery rods designed for the treatment of fungal osteomyelitis: influence of gamma sterilization

Fluconazole poly(D,L-lactic) acid (PLA) and poly(L-lactic) acid (L-PLA) implantable delivery rods were studied, in vitro and in vivo, as an alternative treatment of fungal osteomyelitis. Implantable rods loaded with 5% fluconazole (FLU) were prepared by the injection-molding method and sterilized by gamma-irradiation at a dose of 25 kGy. Loading efficiency, physical chemistry (high performance liquid chromatography, X-ray diffraction, gel permeation chromatography), and in vitro and in vivo release assays were performed to evaluate the novel delivery systems and the sterilization effect on implant characteristics. In spite of polymer degradation after gamma-irradiation, the loading efficiency, chemical stability, and crystallographic structure of FLU were not affected. In vivo studies were carried out in femoral bone marrow of rabbits. Approximately 85 and 80% of the total dose were released within 12 and 4 weeks from PLA and L-PLA rods, respectively. This showed a faster release rate of FLU in vivo than in vitro, showing almost zero-order kinetics from PLA rods.

[Systemic antifungals. Pharmacodynamics and pharmacokinetics]

Invasive fungal infections are important causes of morbidity and mortality in critically ill non neutropenic patients. For many years, amphotericin B and flucytosine have been the only available antifungal agents for invasive fungal infections. Fortunately, the antifungal armamentarium has increased during the past two decades with the addition of several new agents. In addition to itraconazole and fluconazole, lipid formulations of amphotericin B, voriconazole, and caspofungin have been recently licensed. These various antifungal agents differ in their pharmacokinetic and pharmacodynamic profile.

Comparative aspects of coccidioidomycosis in animals and humans

Coccidioides spp. appear capable of infecting all mammals and at least some reptiles. Development of disease as a result of infection is species-dependent. Dogs seem to have a susceptibility similar to that of humans, with subclinical infections, mild-to-severe primary pulmonary disease, and disseminated disease. Whereas central nervous system disease in humans is typically meningitis, brain disease in dogs and cats takes the form of granulomatous parenchymal masses. Osteomyelitis is the most common form of disseminated disease in the dog, while skin lesions predominate in the cat. Orally administered azole antifungal agents are the backbone of therapy in animals as they are in humans.

Involvement of phenobarbital and SKF 525A in the hepatotoxicity of antifungal drugs itraconazole and fluconazole in rats

Itraconazole and fluconazole are potent wide spectrum antifungal drugs. Both of these drugs induce hepatotoxicity clinically. The mechanism underlying the hepatotoxicity is unknown. The purpose of this study was to investigate the role of phenobarbital (PB), an inducer of cytochrome P450 (CYP), and SKF 525A, an inhibitor of CYP, in the mechanism of hepatotoxicity induced by these two drugs in vivo. Rats were pretreated with PB (75 mg/kg for 4 days) prior to itraconazole or fluconazole dosing (20 and 200 mg/kg for 4 days). In the inhibition study, for 4 consecutive days, rats were pretreated with SKF 525A (50 mg/kg) or saline followed by itraconazole or fluconazole (20 and 200 mg/kg) Dose-dependent increases in plasma alanine aminotransferase (ALT), gamma-glutamyl transferase (gamma-GT), and alkaline phosphatase (ALP) activities and in liver weight were detected in rats receiving itraconazole treatment. Interestingly, pretreatment with PB prior to itraconazole reduced the ALT and gamma-GT activities and the liver weight of rats. No changes were observed in rats treated with fluconazole. Pretreatment with SKF 525A induced more severe hepatotoxicity for both itraconazole and fluconazole. CYP 3A activity was inhibited dose-dependently by itraconazole treatment. Itraconazole had no effects on the activity of CYP 1A and 2E. Fluconazole potently inhibited all three isoenzymes of CYP. PB plays a role in hepatoprotection to itraconazole-induced but not fluconazole-induced hepatotoxicity. SKF 525A enhanced the hepatotoxicity of both antifungal drugs in vivo. Therefore, it can be concluded that inhibition of CYP may play a key role in the mechanism of hepatotoxicity induced by itraconazole and fluconazole.

Coccidioidomycosis with cerebral and cerebellar granulomas

We discuss the diagnosis, treatment and prognosis of a Danish male with disseminated coccidioidomycosis. He presented with headaches and slight fever. Examination showed pulmonary, cutaneous and cerebral and cerebellar granulomas, a rare complication. He was treated with intravenously and subsequently orally administered fluconazole. Symptoms and clinical findings regressed during treatment.

Coccidioidomycosis in liver transplantation

Coccidioidomycosis is an endemic fungal infection in the southwestern United States. It causes morbidity and mortality among solid organ transplant recipients who reside in or visit the endemic area or who receive organs from donors infected with the fungus. This paper reviews current literature addressing these infections in liver transplantation programs, including risk factors, clinical manifestations in persons with cirrhosis or who have had a liver transplantation, prophylaxis, treatment, and outcomes.

Pharmacokinetics of fluconazole in the cerebrospinal fluid of children with hydrocephalus

BACKGROUND

The aim of this study was to examine the pharmacokinetics of fluconazole in the CSF of children with hydrocephalus during CNS infection treatment after intravenous and/or intraventricular drug administration. Direct fluconazole administration into the ventricular CSF of patients to treat serious CNS infections is an aggressive therapy, and data on the pharmacokinetics of fluconazole in CSF are limited.

METHODS

A method of fluconazole quantification in CSF by solid-phase extraction (SPE)-high-performance liquid chromatography (HPLC) was developed to conduct pharmacokinetic studies. The population of patients included 2 children with hydrocephalus. Fluconazole was administered intravenously at average multiple doses of 12.5 mg/kg/24 h and intraventricularly at doses of 4, 5 and 7.5 mg/24 h, and 7.5 and 10 mg/12 h. The CSF samples were taken 2-24 h after administration of fluconazole. The concentrations of fluconazole in CSF specimens were assessed, and after pharmacokinetic studies the fluconazole dosage was modified.

RESULTS

The method of fluconazole determination in CSF using the SPE-HPLC method is specific, precise and accurate. After intravenous fluconazole administration, the concentration of this antifungal drug was not detected in the ventricular CSF. The pharmacokinetic parameters determined after intraventricular fluconazole administration were: steady-state peak CSF fluconazole concentration (19.54 +/- 5.63 mg/l); trough CSF fluconazole concentration (0.0-0.3 mg/l); elimination rate constant (0.4654 +/- 0.2097 h(-1)), and half-life (1.84 +/- 0.93 h).

CONCLUSIONS

The authors developed a method to determine fluconazole in CSF by SPE-HPLC. After intravenous fluconazole administration, the drug was not detected in the examined CSF samples. The intraventricular multidose pharmacokinetic data suggest the necessity of fluconazole monitoring in children with hydrocephalus during the treatment of shunt infection.

Current use of anti-infectives in dermatology

Dermatologic diseases encompass a broad category of pathologic situations. Infection remains a significant aspect of the pathology faced in patient encounters, and it is natural to expect that anti-infectives play a major element in the armamentarium utilized by dermatologists. Aside from the treatment of the classic bacterial and fungal infections, there are now new uses for antiviral agents to help suppress recurrent disease, such as herpes simplex. There is also the novel approach of using anti-infectives, or agents that have been thought to have antimicrobial activity, to treat inflammatory diseases. This review describes anti-infectives, beginning with common antibiotics used to treat bacterial infections. The discussion will then cover the current use of antivirals. Finally, the description of antifungals will be separated, starting with the oral agents and ending with the topical antimycotics. The use of anti-infectives in tropical dermatology has been purposefully left out, and perhaps should be the subject of a separate review. Cutaneous bacterial infections consist chiefly of those microorganisms that colonize the skin, such as species of staphylococcus and streptococcus. Propionibacterium acnes and certain other anaerobes can be involved in folliculitis, pyodermas and in chronic conditions such as hidradenitis suppurativa.

Recurrent Candida tropicalis meningitis

Candida meningitis, a previously rare occurrence, has been increasing in prevalence and often is a result of complications of neurosurgery. We describe the case of a 49-year-old man who presented with headache, vertigo, intermittent blurred vision, and multiple episodes of nausea and vomiting. Computed tomography (CT) showed a left cerebellar hemorrhage with obliteration of the fourth ventricle causing hydrocephalus. He had an occipital craniotomy with transcondylar evacuation of the hemorrhage and placement of a temporary ventriculostomy. The hospital stay was prolonged because of postsurgical complications, and Candida tropicalis meningitis developed. Treatment was started with 400 mg of fluconazole administered intravenously every 12 h. In vitro susceptibility testing showed a minimum inhibitory concentration (MIC) to fluconazole of 1 microg/mL. Fluconazole was therefore continued orally for a total of 60 days, and the patient remained asymptomatic for 2 years. He then presented with increased vertigo and ataxia. Cerebrospinal fluid cultures grew C. tropicalis, which again showed susceptibility to fluconazole with a MIC of 1 microg/mL, identical to that in the previous infection. However, a second course of fluconazole failed to control the infection despite adequate cerebrospinal fluid levels.

Central Nervous System Coccidioides immitis Infections

Coccidioidal meningitis occurs in healthy individuals and patients with AIDS or other immunosuppressive illnesses. The central nervous system infection results when Coccidioides immitis disseminates from a primary lung infection via a fungemia to reach the meninges. Cases develop primarily in individuals living in or traveling to the Lower Sonoran Life Zone of Southwest United States. Most cases begin as subacute granulomatous meningitis with occasional patients developing brain abscesses. Diagnosis may be challenging because C. immitis is isolated from cerebrospinal fluid in less than 50% of patients. However, a cerebrospinal fluid complement fixation test for IgG antibody to C. immitis has high sensitivity and specificity. Currently, optimal treatment is unclear. Standard therapy has been with life-long oral fluconazole or intrathecal amphotericin B followed by prolonged oral fluconazole. Liposomal amphotericin B given intravenously seems promising as an initial treatment as it has much higher brain penetration, less nephrotoxicity, and less severe infusion-related adverse effects than conventional amphotericin B. However, current comparative studies for efficacy of liposomal amphotericin B in coccidioidal meningitis are lacking.

Intrapulmonary pharmacokinetics and pharmacodynamics of itraconazole and 14-hydroxyitraconazole at steady state

We determined the steady-state intrapulmonary pharmacokinetic and pharmacodynamic parameters of orally administered itraconazole (ITRA), 200 mg every 12 h (twice a day [b.i.d.]), on an empty stomach, for a total of 10 doses, in 26 healthy volunteers. Five subgroups each underwent standardized bronchoscopy and bronchoalveolar lavage (BAL) at 4, 8, 12, 16, and 24 h after administration of the last dose. ITRA and its main metabolite, 14-hydroxyitraconazole (OH-IT), were measured in plasma, BAL fluid, and alveolar cells (AC) using high-pressure liquid chromatography. Half-life and area under the concentration-time curves (AUC) in plasma, epithelial lining fluid (ELF), and AC were derived using noncompartmental analysis. ITRA and OH-IT maximum concentrations of drug (C(max)) (mean +/- standard deviation) in plasma, ELF, and AC were 2.1 +/- 0.8 and 3.3 +/- 1.0, 0.5 +/- 0.7 and 1.0 +/- 0.9, and 5.5 +/- 2.9 and 6.6 +/- 3.1 microg/ml, respectively. The ITRA and OH-IT AUC for plasma, ELF, and AC were 34.4 and 60.2, 7.4 and 18.9, and 101 and 134 microg. hr/ml. The ratio of the C(max) and the MIC at which 90% of the isolates were inhibited (MIC(90)), the AUC/MIC(90) ratio, and the percent dosing interval above MIC(90) for ITRA and OH-IT concentrations in AC were 1.1 and 3.2, 51 and 67, and 100 and 100%, respectively. Plasma, ELF, and AC concentrations of ITRA and OH-IT declined monoexponentially with half-lives of 23.1 and 37.2, 33.2 and 48.3, and 15.7 and 45.6 h, respectively. An oral dosing regimen of ITRA at 200 mg b.i.d. results in concentrations of ITRA and OH-ITRA in AC that are significantly greater than those in plasma or ELF and intrapulmonary pharmacodynamics that are favorable for the treatment of fungal respiratory infection.

History of the development of azole derivatives

Until the 1940s, relatively few agents were available for the treatment of systemic fungal infections. The development of the polyene antifungals represented a major advance in medical mycology. Although amphotericin B quickly became the mainstay of therapy for serious infections, its use was associated with infusion-related side-effects and dose-limiting nephrotoxicity. The continued search for new and less toxic antifungals led to the discovery of the azoles several decades later. Ketoconazole, the first available compound for the oral treatment of systemic fungal infections, was released in the early 1980s. For almost a decade, ketoconazole was regarded as the drug of choice in nonlife-threatening endemic mycoses. The introduction of the first-generation triazoles represented a second major advance in the treatment of fungal infections. Both fluconazole and itraconazole displayed a broader spectrum of antifungal activity than the imidazoles and had a markedly improved safety profile compared with amphotericin B and ketoconazole. Despite widespread use, however, these agents became subject to a number of clinically important limitations related to their suboptimal spectrum of activity, the development of resistance, the induction of hazardous drug-drug interactions, their less than optimal pharmacokinetic profile (itraconazole capsules), and toxicity. In order to overcome these limitations, several analogues have been developed. These so-called 'second-generation' triazoles, including voriconazole, posaconazole and ravuconazole, have greater potency and possess increased activity against resistant and emerging pathogens, in particular against Aspergillus spp. If the toxicity profile of these agents is comparable to or better than that of the first-generation triazoles and drug interactions remain manageable, then these compounds represent a true expansion of our antifungal arsenal.

Amphotericin B lipid complex for the treatment of invasive fungal infections

Amphotericin B lipid complex (ABLC; Abelcet, Enzon Pharmaceuticals) has become the dominant marketed lipid amphotericin B compound to emerge since the approval of these agents from the mid-1990s onwards. This agent is a 1:1 combination of amphotericin B and a lipid moiety consisting of dimyristoyl phosphatidylcholine and dimyrisoyl phosphatidylcholine, which exists in a ribbon-like molecular structure. ABLC undergoes rapid reticuloendothelial uptake from the circulation and achieves significantly higher tissue concentrations in the liver, spleen and lung compared to comparably dosed conventional amphotericin B. ABLC is approved by the FDA for all mycoses in amphotericin B-intolerant or -refractory infection. Randomised, controlled trials of amphotericin B have shown comparable efficacy in candidiasis and an improved outcome in invasive aspergillosis versus historical controls. ABLC has demonstrated a reduced incidence of nephrotoxicity and infusion reactions versus amphotericin B. Comparative studies against other lipid formulations are quite limited and have shown variable differences in infusion toxicity, nephrotoxicity, hepatotoxicity and clinical efficacy. Postapproval experience has shown substantial efficacy for less common mycotic pathogens including zygomycosis. The precise position of ABLC versus both other lipid formulations and expanding formulary of new antifungal agents is in flux. Future studies which examine its clinical efficacy, role in combination therapy, toxicity and cost-effectiveness in these complex patients are needed.

Systemic Antifungal Therapy: New Options, New Challenges

The frequency of invasive fungal infections has increased dramatically in recent decades because of an expanding population at risk. Until now, treatment options for invasive mycoses have been primarily amphotericin B and the azoles, fluconazole and itraconazole. Traditional agents are limited by an inadequate spectrum of activity, drug resistance, toxicities, and drug-drug interactions. The recent approval of caspofungin and voriconazole clearly has expanded the number of existing antifungal drugs available. However, the enthusiasm that accompanies their availability is counterbalanced by limited clinical experience, high drug acquisition costs, and distinctive toxicities. The pharmacologic characteristics, extent of clinical experience (efficacy and toxicity), and drug acquisition costs among available systemic antifungal agents are compared, with emphasis on the new agents. Also, recommendations on the role of each agent are provided according to the most common indications for systemic antifungal therapy: invasive candidiasis, invasive aspergillosis, and febrile neutropenia.

Central nervous system candidiasis in the high-risk neonate

Central nervous system involvement in neonatal candidiasis is not rare, although possibly less frequent than in previous decades. In addition to increasing the potential for neurodevelopmental morbidity, this infection poses major challenges in establishing diagnosis and assuring adequate treatment. In the setting of candidemia or other severe invasive candida disease, suggestive imaging studies or inflammatory changes in cerebrospinal fluid should prompt careful consideration of central nervous system candidiasis even if culture of the fluid is negative. Although delivery of amphotericin to cerebrospinal fluid appears much better in premature infants than in older individuals, the availability of other agents with superior delivery to the central nervous system suggests that strong consideration be given to their use as alternative or adjunct therapy if central nervous system involvement appears likely. Careful surveillance for neurodevelopmental sequelae may permit early detection, timely rehabilitative intervention, and potentially better long-term functional outcomes.

Caspofungin acetate for treatment of invasive fungal infections

OBJECTIVE

To briefly discuss the changing epidemiology of fungal infections and review currently available agents; provide a review of caspofungin; and discuss its pharmacology, pharmacokinetics, dosing guidelines, safety and efficacy, and role in the treatment of invasive fungal infections as it relates to current antifungal therapy.

DATA SOURCES

A MEDLINE (1966 to August 2002) database search using key words caspofungin, echino candins, fungal infections, and invasive aspergillosis, was completed to identify relevant articles including reviews, recent studies, treatment guidelines, and data from Merck and Company.

STUDY SELECTION

In vitro studies and all clinical trials were evaluated to summarize the clinical efficacy and safety of caspofungin.

DATA SYNTHESIS

The incidence of fungal infections is increasing as the population at risk expands. Cost, resistance, and morbidity and mortality are key issues. Adding to the antifungal armamentarium is necessary to address these therapeutic dilemmas. Caspofungin is the first member of a new class of antifungal agents, the echinocandins, to be approved for clinical use. Caspofungin is classified as a glucan synthase inhibitor and represents a class of agents with a novel mechanism of action. Unlike currently available agents (polyenes, pyrimidines, azoles) that exert their effect on the fungal cell membrane, the echinocandins are the first agents to inhibit fungal cell wall synthesis. Caspofungin exhibits activity against Aspergillus spp. and Candida spp., including non-albicans species. Data from clinical trials demonstrate that caspofungin is effective in patients with invasive aspergillosis as well as candida esophagitis. Its Food and Drug Administration-approved indication is limited to invasive aspergillosis refractory to or intolerant of current therapy.

CONCLUSIONS

Caspofungin has activity against Aspergillus spp. as well as a variety of Candida spp. Clinical data support its usefulness in the treatment of invasive aspergillosis and select candida infections. As additional clinical data become available, it seems likely that the therapeutic role of caspofungin will expand.

Antifúngicos de uso sistémico

Invasive fungal infection is the infectious complication with highest associated mortality. Until the 90's amphotericin B was the only drug available to treat these infections. Its spectrum of antifungal activity is excellent, but its use is associated with toxicity in many cases. The development of amphotericin B lipid formulations has resulted in a significant decrease in most of the side effects associated with this drug. Triazoles are safe and effective for treating most invasive fungal infections. Fluconazole is an excellent drug for the prevention and treatment of Candida and Cryptococcus infections, itraconazole has good activity against Candida and Aspergillus, and voriconazole has shown to be better than amphotericin B for invasive aspergillosis. Caspofungin belongs to a new group of antifungal agents, the echinocandins, which are very safe and present excellent activity against Candida and Aspergillus.

Probable case of torsades de pointes induced by fluconazole

A 25-year-old woman who was hospitalized for worsening endocarditis had a prolonged QT interval at baseline and developed monomorphic ventricular arrhythmias, which were managed successfully with pacing and antiarrhythmic therapy. Several days later, the patient started receiving high-dose fluconazole for fungemia and subsequently experienced episodes of torsades de pointes, a polymorphic ventricular arrhythmia associated with a prolonged QT interval or prominent U wave on the electrocardiogram. The arrhythmia developed in the presence of known risk factors. Clinicians should be aware of these risk factors and other relevant structural similarities with drugs that cause torsades de pointes so that they can recognize patients who may be at risk for fluconazole-associated arrhythmia.

Paracoccidioidomycosis: report of 2 cases mimicking squamous cell carcinoma

Paracoccidioidomycosis is an endemic fungal infection in Latin America. This mucocutaneous disease often involves the oral mucosa and may clinically resemble other infectious and neoplastic processes. Paracoccidioidomycosis that clinically suggested squamous cell carcinoma was diagnosed in 2 patients with a history of heavy alcohol and tobacco use. Antifungal therapy with ketoconazole and itraconazole resulted in resolution of the oral lesions. Interestingly, 1 patient had a pulmonary lesion that persisted after antifungal therapy, and biopsy proved this to be a squamous cell carcinoma of the lung.

Antifungal and antiviral chemotherapy

Fungal and viral infections are difficult to treat, since fungal infections commonly rebound after suppression by the antifungal agent and current antiviral drugs are only virustatic, allowing the virus to reassert its pathogenicity if not eliminated by the host defenses. In addition, fungal infections commonly are associated with significant biofilms, retarding drug penetration, and the fluid nature of the oral cavity does not promote drug-fungus contact for long periods of time. Both mycotic and viral pathogens are developing sophisticated methods to elude the toxic effects of drugs intended to eliminate their existence. The drug therapy of oral fungal and viral infections is therefore limited but occasionally successful (more with fungal than viral infections) and is often relegated to palliative care. The specter of drug resistance and its promotion by prolonged, repetitive and frivolous use must always be foremost in the clinician's mind.

Commonly used antibacterial and antifungal agents for hospitalised paediatric patients: implications for therapy with an emphasis on clinical pharmacokinetics

Due to normal growth and development, hospitalised paediatric patients with infection require unique consideration of immune function and drug disposition. Specifically, antibacterial and antifungal pharmacokinetics are influenced by volume of distribution, drug binding and elimination, which are a reflection of changing extracellular fluid volume, quantity and quality of plasma proteins, and renal and hepatic function. However, there is a paucity of data in paediatric patients addressing these issues and many empiric treatment practices are based on adult data. The penicillins and cephalosporins continue to be a mainstay of therapy because of their broad spectrum of activity, clinical efficacy and favourable tolerability profile. These antibacterials rapidly reach peak serum concentrations and readily diffuse into body tissues. Good penetration into the cerebrospinal fluid (CSF) has made the third-generation cephalosporins the agents of choice for the treatment of bacterial meningitis. These drugs are excreted primarily by the kidney. The carbapenems are broad-spectrum beta-lactam antibacterials which can potentially replace combination regimens. Vancomycin is a glycopeptide antibacterial with gram-positive activity useful for the treatment of resistant infections, or for those patients allergic to penicillins and cephalosporins. Volume of distribution is affected by age, gender, and bodyweight. It diffuses well across serous membranes and inflamed meninges. Vancomycin is excreted by the kidneys and is not removed by dialysis. The aminoglycosides continue to serve a useful role in the treatment of gram-negative, enterococcal and mycobacterial infections. Their volume of distribution approximates extracellular space. These drugs are also excreted renally and are removed by haemodialysis. Passage across the blood-brain barrier is poor, even in the face of meningeal inflammation. Low pH found in abscess conditions impairs function. Toxicity needs to be considered. Macrolide antibacterials are frequently used in the treatment of respiratory infections. Parenteral erythromycin can cause phlebitis, which limits its use. Parenteral azithromycin is better tolerated but paediatric pharmacokinetic data are lacking. Clindamycin is frequently used when anaerobic infections are suspected. Good oral absorption makes it a good choice for step-down therapy in intra-abdominal and skeletal infections. The use of quinolones in paediatrics has been restricted and most information available is in cystic fibrosis patients. High oral bioavailability is also important for step-down therapy. Amphotericin B has been the cornerstone of antifungal treatment in hospitalised patients. Its metabolism is poorly understood. The half-life increases with time and can be as long as 15 days after prolonged therapy. Oral absorption is poor. The azole antifungals are being used increasingly. Fluconazole is well tolerated, with high bioavailability and good penetration into the CSF. Itraconazole has greater activity against aspergillus, blastomycosis, histoplasmosis and sporotrichosis, although it's pharmacological and toxicity profiles are not as favourable.

Itraconazole- and fluconazole-induced toxicity in rat hepatocytes: a comparative in vitro study

This current study was to investigate the in vitro cytotoxicity of rat hepatocytes induced by the antifungal drugs, itraconazole and fluconazole. Both antifungal drugs caused dose-dependent cytotoxicity. In vitro incubation of hepatocytes with itraconazole revealed significantly higher lactate dehydrogenase (LDH) leakage when compared to fluconazole. Phenobarbital pretreated hepatocytes contained significantly higher total cytochrome P450 content than the control hepatocytes. P450 content was reduced approximately 30% for both types of hepatocytes after 6 hours incubation. Interestingly, cytotoxicity of itraconazole was reduced significantly by phenobarbital pretreatment. Phenobarbital did not have any effect on the cytotoxicity induced by fluconazole. These results demonstrate the in vitro toxicity of hepatocytes induced by itraconazole and fluconazole that were expressed in a dose- and time-dependent manner. Phenobarbital plays a role in the cytoprotection of hepatocytes to itraconazole-induced but not fluconazole-induced cytotoxicity in vitro.