Echinocandins: A ray of hope in antifungal drug therapy

Invasive fungal infections are on the rise. Amphotericin B and azole antifungals have been the mainstay of antifungal therapy so far. The high incidence of infusion related toxicity and nephrotoxicity with amphotericin B and the emergence of fluconazole resistant strains of Candida glabrata egged on the search for alternatives. Echinocandins are a new class of antifungal drugs that act by inhibition of β (1, 3)-D- glucan synthase, a key enzyme necessary for integrity of the fungal cell wall.Caspofungin was the first drug in this class to be approved. It is indicated for esophageal candidiasis, candidemia, invasive candidiasis, empirical therapy in febrile neutropenia and invasive aspergillosis. Response rates are comparable to those of amphotericin B and fluconazole. Micafungin is presently approved for esophageal candidiasis, for prophylaxis of candida infections in patients undergoing hematopoietic stem cell transplant (HSCT) and in disseminated candidiasis and candidemia. The currently approved indications for anidulafungin are esophageal candidiasis, candidemia and invasive candidiasis.The incidence of infusion related adverse effects and nephrotoxicity is much lower than with amphotericin B. The main adverse effect is hepatotoxicity and derangement of serum transaminases. Liver function may need to be monitored. They are, however, safer in renal impairment. Even though a better pharmacoeconomical choice than amphotericin B, the higher cost of these drugs in comparison to azole antifungals is likely to limit their use to azole resistant cases of candidial infections and as salvage therapy in invasive aspergillosis rather than as first line drugs.     

Candidemia in children

Abstract

Seriously ill or immunocompromised children are at increased risk of invasive fungal infections, particularly candidemia. Candida albicans and Candida parapsilosis are the two most frequent causes of candidemia in pediatric patients. Candidemia in children is associated with high morbidity and mortality, increased length of hospital stays, and higher healthcare costs. Early effective antifungal therapy is the key to improved outcomes. Risk factors for candidemia may be used to identify patients suitable for empiric therapy. Such risk factors include prolonged stay in an intensive care unit, immunosuppression, prior bacterial infection, and recent surgery, as well as the use of a central venous catheter, mechanical ventilation, and/or total parenteral nutrition. Recent guidelines from the Infectious Diseases Society of America recommend consideration of fluconazole or an echinocandin for empiric therapy in suitable candidates, with a preference for an echinocandin in patients with moderate-to-severe disease, recent azole exposure, or high risk of Candida glabrata or Candida krusei infection. Fluconazole or an echinocandin is also preferred initial therapy for non-neutropenic candidemia, depending on disease severity and other characteristics. The guidelines recommend treatment with an echinocandin or lipid formulation of amphotericin B for most patients with neutropenic candidemia, although fluconazole is identified as an alternative for less critically ill patients without recent azole exposure. Risk factors for candidemia – and, hence, criteria for prophylaxis – are less well established in older children than in neonates. Further research is needed to better establish criteria for antifungal prophylaxis in children at high risk for candidemia.     

Candida endophthalmitis: focus on current and future antifungal treatment options

Candida endophthalmitis is a sight-threatening manifestation of disseminated candidiasis. The occurrence of endogenous candida endophthalmitis in patients with candidemia has ranged from 0-45% in the published literature. In critically ill patients, it has even been associated with increased mortality. In recent years, use of newer antifungal therapies for invasive candidiasis has increased given the rise in infections with non-albicans species of Candida. To identify current practices of the management of endogenous candida endophthalmitis and relevant antifungal drug research in this disease state, we conducted a MEDLINE search (1967-2006) and bibliographic search of the English-language literature. Treatments for candida endophthalmitis have not been evaluated through well-designed, well-powered clinical trials. Data have mainly been presented in case reports, case series, animal studies, pharmacokinetic studies, and as small subsets of larger trials. Traditional systemic therapies have been amphotericin B with or without flucytosine or fluconazole. Cure rates with antifungal drugs alone appear to be much higher in patients with chorioretinitis than in endophthalmitis with vitreal involvement. Pars plana vitrectomy with or without intravitreal amphotericin B injections has been advocated particularly for patients with moderate-to-severe vitritis and substantial vision loss. Information on new antifungal agents for endophthalmitis is limited, despite increasing use in patients with candidemia. Voriconazole may be a particularly attractive agent to consider for infections with fluconazole-resistant, voriconazole-susceptible strains. The current patchwork of animal studies and small patient reports provide clinicians with some insight into the role of newer agents in the treatment of candida endophthalmitis. In general, it appears that chorioretinitis infections can be more readily cured with most systemic antifungal agents, whereas more aggressive treatment, often including vitrectomy with or without intra-vitreal antifungal administration, is needed for patients with endophthalmitis with vitritis.     

Management of systemic candidal infections in the intensive care unit.

Risk factors and treatment strategies for systemic candidal infections in the intensive care unit (ICU) are discussed. The past two decades have seen a dramatic increase in the frequency of infections caused by Candida species. Risk factors associated with candidemia include treatment with multiple antimicrobials for extended periods, presence of central venous catheters, total parenteral nutrition, colonization by Candida species, abdominal surgery, prolonged stay in the ICU, and compromised immune status. Since the 1960s, conventional amphotericin B has been the primary treatment option for fungal infections. Although effective, amphotericin B has extensive toxicity. Three lipid-based formulations of amphotericin B have been developed in an attempt to decrease nephrotoxicity and improve drug delivery. Practitioners have also been offered alternatives by the introduction of less toxic azole antifungals, such as ketoconazole, fluconazole, and itraconazole; however, their widespread use has resulted in other problems, such as the selection of resistant isolates. There is controversy concerning fluconazole's effectiveness. In the treatment of systemic candidal infections, especially in critically ill patients. Clinical trials do not support the prophylactic or empirical use of fluconazole in the ICU. Treating patients who have no microbiological evidence of infection provides no therapeutic benefit and shifts the fungal flora to noncandidal strains that are more resistant to fluconazole. Patients in ICUs are often susceptible to systemic candidal infection. Preemptive therapy with fluconazole may reduce mortality in high-risk patients. Fluconazole and amphotericin B appear equally effective in treating established systemic candidal infections.     

Anidulafungin: an evidence-based review of its use in invasive fungal infections

INTRODUCTION: Anidulafungin is a new echinocandin antifungal agent with indications for use in esophageal candidiasis and candidemia. The mortality and morbidity associated with fungal infections in healthcare facilities necessitates the development of new treatment options for these diseases. AIMS: This review assesses the pharmacology and evidence for the use of anidulafungin in the treatment of serious fungal infections. EVIDENCE REVIEW: There is substantial evidence that anidulafungin is a potent antifungal agent with activity against a broad range of fungal species. Likewise, evidence supports that anidulafungin is a well-tolerated antifungal agent. Clinical studies provide sufficient evidence for regulatory approval for esophageal candidiasis and candidemia, and limited evidence suggests that anidulafungin may be superior to fluconazole for candidemia and invasive candidiasis. The introduction of anidulafungin into clinical practice adds a third option for therapy in the echinocandin class. Research into its efficacy in other fungal infections is ongoing, and further studies into the impact of anidulafungin on economic outcomes will be beneficial. PLACE IN THERAPY: Current evidence supports the use of anidulafungin in the management of candidemia, esophageal candidiasis, and invasive candidiasis, as demonstrated by the successful results in large multicenter clinical trials.     

Caspofungin: a review of its use in the treatment of fungal infections

Caspofungin (Cancidas) is the first of a new class of antifungal agents, the echinocandins, that inhibit the synthesis of the fungal cell wall component beta-(1,3)-D-glucan. Caspofungin is administered once daily by slow intravenous infusion and is used to treat infections caused by Candida spp. and Aspergillus spp.Caspofungin is a valuable new antifungal agent with a novel mechanism of action. In comparative clinical trials, caspofungin was no less effective than liposomal amphotericin B in the empirical treatment of neutropenic patients with persistent fever, amphotericin B deoxycholate in the treatment of invasive candidiasis or fluconazole in the treatment of oesophageal candidiasis. Caspofungin also displayed broadly similar efficacy to amphotericin B deoxycholate in oesophageal or oropharyngeal candidiasis and was effective as salvage therapy in patients with invasive aspergillosis who were refractory to or intolerant of standard therapy. The tolerability profile of caspofungin was similar to that of fluconazole and superior to that of amphotericin B deoxycholate and liposomal amphotericin B. Therefore, in the appropriate indications, caspofungin is a viable alternative to amphotericin B deoxycholate, liposomal amphotericin B or fluconazole.     

The echinocandins: comparison of their pharmacokinetics, pharmacodynamics and clinical applications

Caspofungin, micafungin and anidulafungin are three drugs of the echinocandin class of antifungals available for intravenous treatment of invasive candidiasis and aspergillosis. They exhibit high in vitro and in vivo activities against Candida spp. and Aspergillus spp. In various clinical studies investigating candidemia and invasive candidiasis, Candida esophagitis, and fever in neutropenia, the clinical efficacy of the echinocandin tested was similar to that of established antifungals. Antifungal activity against strains no longer susceptible to conventional antifungal agents, such as fluconazole and amphotericin B suggests that echinocandins can be used as salvage therapy in life-threatening fungal infections. There is no cross-resistance to other antifungals. Excellent safety and tolerability of treatment with caspofungin has been documented over a total of 4.3 million patient days. Echinocandins are poor substrates of the cytochrome P450 enzyme family and can be safely co-administered with most drugs without the need for dosage adaptation. No dose reduction is required in renal impairment. A reduction in the daily maintenance dose has been recommended for caspofungin, but not for micafungin and anidulafungin in patients presenting with mild to moderate hepatic failure.     

Caspofungin: a review of its use in oesophageal candidiasis, invasive candidiasis and invasive aspergillosis

Echinocandins are a new class of antifungal agents with a novel mechanism of action (interference with fungal cell wall synthesis). Caspofungin (Cancidas), Caspofungin MSD) is the first echinocandin to be approved and is administered intravenously.Caspofungin 50 mg/day had similar efficacy to intravenous fluconazole 200 mg/day and was at least as effective as intravenous amphotericin B 0.5 mg/kg/day in patients with oesophageal candidiasis in two randomised, double-blind studies. A favourable combined clinical and endoscopic response occurred in 81% of caspofungin recipients versus 85% of fluconazole recipients and in 74% of caspofungin recipients versus 63% of amphotericin B recipients. A favourable combined response rate of approximate, equals 90% and approximate, equals 60% occurred in the stratum of patients with oesophageal candidiasis who received caspofungin or amphotericin B in a third randomised, double-blind study.Caspofungin (70 mg loading dose followed by 50 mg/day) had similar efficacy to intravenous amphotericin B (0.7-1.0 mg/kg/day in patients with neutropenia and 0.6-0.7 mg/kg/day in patients without neutropenia) in patients with invasive candidiasis in a double-blind, randomised trial. A favourable overall response occurred in 73.4% of caspofungin recipients and in 61.7% of amphotericin B recipients.In a noncomparative study, salvage therapy with caspofungin (70 mg loading dose followed by 50 mg/day) was effective in patients with invasive aspergillosis who were refractory to or did not tolerate standard antifungal therapy. A favourable response (complete plus partial response) occurred in 37 of 83 patients (45%).Caspofungin was generally well tolerated in clinical trials; it had similar tolerability to intravenous fluconazole and was better tolerated than intravenous amphotericin B. Significantly fewer caspofungin than amphotericin B recipients reported chills, fever, nausea or infusion-related adverse events. In conclusion, caspofungin is a valuable new antifungal agent with a novel mechanism of action. In comparative trials, caspofungin had similar efficacy to fluconazole and was at least as effective as amphotericin B in oesophageal candidiasis and had similar efficacy to amphotericin B in invasive candidiasis. In addition, caspofungin had similar tolerability to fluconazole and was better tolerated than amphotericin B in these indications. Caspofungin was also effective in patients with invasive aspergillosis who were refractory to or intolerant of standard antifungal agents. Thus, caspofungin provides an alternative to triazoles or amphotericin B in oesophageal candidiasis and an alternative to amphotericin B in invasive candidiasis, as well as being an effective salvage therapy in invasive aspergillosis.     

Pharmacokinetic evaluation of fluconazole in critically ill patients

INTRODUCTION: Invasive candidiasis has emerged over the last few decades as an increasingly important nosocomial problem for the critically ill, affecting around 2% of intensive care unit patients. Although poor outcomes associated with invasive candidiasis among critically ill patients may relate to severe underlying disease processes and delayed institution of antifungal therapy, inadequate dosing of antifungal agents may also contribute. AREAS COVERED: This drug evaluation provides a critical appraisal of the published literature pertaining to the pharmacokinetics of fluconazole in critically ill, obese or severely burned patients, including those receiving acute renal replacement therapy. The pharmacodynamics of fluconazole is also covered, as well as the likely clinical implications for optimal dosing and the toxicity of fluconazole. Last, variations in fluconazole susceptibility patterns of Candida spp. are also discussed. EXPERT OPINION: Recently, there has been an increased but geographically variable prevalence of non-albicans Candida spp., causing invasive candidiasis and an overall trend towards reduced fluconazole susceptibility. The pathophysiological changes of critical illness, coupled with a lack of dose finding studies, support the use of local susceptibility patterns to guide fluconazole dosing until such time as pharmacokinetic-pharmacodynamic information to guide optimal fluconazole dosing strategies and pharmacodynamic targets becomes available.     

Anidulafungin: an evidence-based review of its use in invasive fungal infections

Introduction:

Anidulafungin is a new echinocandin antifungal agent with indications for use in esophageal candidiasis and candidemia. The mortality and morbidity associated with fungal infections in healthcare facilities necessitates the development of new treatment options for these diseases.

Aims:

This review assesses the pharmacology and evidence for the use of anidulafungin in the treatment of serious fungal infections.

Evidence review:

There is substantial evidence that anidulafungin is a potent antifungal agent with activity against a broad range of fungal species. Likewise, evidence supports that anidulafungin is a well-tolerated antifungal agent. Clinical studies provide sufficient evidence for regulatory approval for esophageal candidiasis and candidemia, and limited evidence suggests that anidulafungin may be superior to fluconazole for candidemia and invasive candidiasis. The introduction of anidulafungin into clinical practice adds a third option for therapy in the echinocandin class. Research into its efficacy in other fungal infections is ongoing, and further studies into the impact of anidulafungin on economic outcomes will be beneficial.

Place in therapy:

Current evidence supports the use of anidulafungin in the management of candidemia, esophageal candidiasis, and invasive candidiasis, as demonstrated by the successful results in large multicenter clinical trials.     

Echinocandins: role in antifungal therapy, 2005

Novel therapies to treat invasive fungal infections have revolutionised the care of patients with candidiasis, aspergillosis and other less common fungal infections. Physicians in the twenty first century have access to safer versions of conventional drugs (i.e., lipid amphotericin B products), extended-spectrum versions of established drugs (i.e., voriconazole), as well as a new class of antifungal agents; the echinocandins. The increased number of options in the antifungal armamentarium is well timed, as the incidence of both invasive candidiasis and invasive aspergillosis, and the financial burden associated with these infections, have increased significantly in the past several decades. The increasing incidence of fungal infections has risen in parallel with the increase in critically ill and immunocompromised patients. Candida is the fourth most common bloodstream isolate, approximately 50% of which are non-albicans species. Estimates suggest there to be 9.8 episodes of invasive candidiasis per 1000 admissions to surgical intensive care units, with attributable mortality at 30% and cost per episode of US44,000 dollars. The burden of candidiasis is even higher in the paediatric population, with Candida being the second most common bloodstream infection. The increase in non-albicans candidiasis mandates the introduction of new antifungal agents capable of treating these often azole-resistant isolates. In addition, there has been a rise in the incidence of invasive aspergillosis, the most common invasive mould infection following haematopoietic stem cell transplantation, with an estimated incidence of 10 - 20%. The mortality associated with invasive aspergillosis has increased by 357% since 1980. Unfortunately, the overall survival rate among patients treated with amphotericin B, and even voriconazole, remains suboptimal, as evidenced by the failure of treatment in 47% of patients in the landmark voriconazole versus amphotericin B trial. Given the increasing incidence and suboptimal outcomes of these serious fungal infections, novel therapies represent an opportunity for significant advancement in clinical care. The current challenge is to discover the optimal place for the echinocandins in the treatment of invasive fungal infections.     

Anidulafungin: a new echinocandin for the treatment of fungal infections

Immunocompromised hosts are at increased risk for invasive fungal infections. Over the last five decades, the mainstay of therapy against systemic mycoses has revolved around amphotericin B deoxycholate. Unfortunately, this drug has substantial toxicities, and agents such as fluconazole were developed as an alternative to treat and prevent these invasive infections. Due to widespread use, fluconazole-resistant organisms have emerged; therefore, new agents with improved safety, efficacy and tolerability have now become desirable. The echinocandins are a new class of antifungal agents with novel activity against the fungal cell wall. In February 2006, the U.S. Food and Drug Administration approved the echinocandin anidulafungin for the treatment of patients with candidemia, peritonitis, intra-abdominal abscesses and esophageal candidiasis.     

Options for the Management of Mucosal Candidiasis in Patients with AIDS and HIV Infection

Oropharyngeal candidiasis may be the first manifestation of human immunodeficiency viral (HIV) infection, and more than 90% of patients with the acquired immunodeficiency syndrome (AIDS) develop the disease. Although numerous antifungal agents are available, azoles, both topical (clotrimazole) and systemic (fluconazole, itraconazole), have largely replaced older topical antifungals (gentian violet, nystatin) in the management of the disease in these patients. A concern in these patients is clinical relapse, which appears to be dependent on degree of immunosuppression and is more common with clotrimazole and ketoconazole than with fluconazole or itraconazole. Candida esophagitis is also of concern, since it occurs in more than 10% of patients with AIDS. Fluconazole is an integral part of management. A cyclodextrin oral solution formulation of itraconazole has similar clinical response rates as fluconazole and is an effective alternative. In patients with fluconazole-resistant mucocutaneous candidiasis, treatment options include itraconazole and amphotericin B oral suspension and parenteral preparation.     

Fluconazole. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in superficial and systemic mycoses

Fluconazole is a bis-triazole antifungal drug with novel pharmacokinetic properties (metabolic stability, relatively high water solubility) which contribute to its therapeutic activity. Clinical experience is limited to a relatively small number of mycoses and, as might be expected at this early stage of development, optimal dosage and duration of treatment for some serious mycoses is not yet established. Further study to evaluate higher dosages and to establish the efficacy of fluconazole relative to more established antifungal agents is required. In patients with oropharyngeal or oesophageal candidiasis, fluconazole produces rapid relief and eradicates the yeast in 50 to 90% of patients. Relapse of oral infection is common in chronically immunocompromised patients regardless of the antifungal used, and adequate primary therapy plus long term prophylaxis appears necessary in patients with AIDS. A single oral dose of fluconazole was comparable to standard topical azole therapy in women with acute vaginal candidiasis. Preliminary reports of success against deep-seated candidiasis are encouraging; moreover, experience in noncomparative clinical trials suggests that fluconazole 200 to 400mg once daily resolves infection in the majority of seriously ill patients. Clinical improvement has been reported in a few cases of pulmonary Aspergillus infection but the overall efficacy of conventional dosages of fluconazole in this mycosis has not been as impressive. Early experience in coccidioidosis, predominantly meningitis, suggests a beneficial clinical effect with oral fluconazole in this difficult to treat mycosis but relapse remains a problem. Fluconazole is a promising treatment of cryptococcal meningitis. The rate of clinical resolution and eradication of Cryptococcus neoformans from cerebrospinal fluid has been similar between fluconazole and amphotericin B treatment groups in comparative trials. Comparative trials of maintenance therapy indicate a similar low rate of relapse among patients given oral fluconazole once daily and intravenous amphotericin B once weekly. However, these results are preliminary and further study is required. Fluconazole has been well tolerated to date but wider clinical experience is needed, especially with regard to the rate occurrence of hepatotoxicity and exfoliative skin reactions. The promising clinical response of patients with various forms of candidiasis or cryptococcosis--together with convenient administration regimens--recommends fluconazole as a useful addition to currently available systemic antifungal therapies, in particular for the treatment of mycoses in patients with AIDS.     

Pharmacologic and clinical evaluation of posaconazole

Posaconazole, a broad-spectrum triazole antifungal agent, is approved for the prevention of invasive aspergillosis and candidiasis in addition to the treatment of oropharyngeal candidiasis. There is evidence of efficacy in the treatment and prevention of rarer, more difficult-to-treat fungal infections. Posaconazole oral suspension solution has shown limitations with respect to fasting state absorption, elevated gastrointestinal pH and increased motility. The newly approved delayed-release oral tablet and intravenous solution formulations provide an attractive treatment option by reducing interpatient variability and providing flexibility in critically ill patients. On the basis of clinical experience and further clinical studies, posaconazole was found to be a valuable pharmaceutical agent for the treatment of life-threatening fungal infections. This review will examine the development history of posaconazole and highlight the most recent advances.     

Developments in the treatment of candidiasis: more choices and new challenges

The incidence of oesophageal candidiasis, candidaemia and disseminated candidiasis has increased dramatically. In addition to the amphotericin B formulations and fluconazole, the echinocandins anidulafungin, caspofungin and micafungin and the newer triazoles posaconazole and voriconazole are in the last stages of development and are becoming available for the management of candidiasis. This review presents these new agents and addresses their role in the treatment of candidiasis. All new antifungal agents exhibit potent activity against Candida spp. and echinocandins are fungicidal against most Candida spp. but appear to be less potent against certain species, such as Candida parapsilosis and C. guilliermondii. Systemic antifungal therapy can now be individualised based on the severity of the infection, comorbid conditions and the Candida spp. causing the infection. Studies are needed to investigate the possible development of resistance and the efficacy of these antifungal agents against the more resistant Candida spp.     

Epidemiology of Candida albicans infections and role of non-Candida-albicans yeasts

Infections of the skin and the mucous membranes due to Candida species may occur either in immuncompromised or in non-immuncompromised patients. This is in contrast to systemic candidiasis (e.g. candidemia) which is only seen in severely immunocompromised patients. Bloodstream infections caused by Candida species are increasingly recognized in critical ill adult and pediatric individuals, with significant associated morbidity and mortality. Candida albicans is the single most common fungal species causing nosocomial infections. However, non-Candida albicans spp., including fluconazole-less-susceptible Candida glabrata, have become more common pathogens. In some patient populations such as hematological (neutropenic) patients Non-C. albicans species are detected much more frequently as compared to non-neutropenic patients in the intensive care. Non-C. albicans species are more likely to occur in patients, who receive or have received antifungal therapy with azoles (e.g. fluconazole). In this review the current epidemiological trends in mucosal and invasive candidiasis are discussed with regard to the role of non-Candida albicans species as the causative agent in immunocompromised patients.     

Management of invasive candidiasis in critically ill patients

Candida species have become predominant pathogens in critically ill patients. In this population, invasive candidiasis is associated with a poor prognosis but adequate management can limit the attributable mortality. Adequate management, however, is hampered by a problematic diagnosis as the clinical picture of invasive disease is non-specific and blood cultures have a low sensitivity. Moreover, it is often hard to differentiate colonisation from infection and many critically ill patients are heavily colonised with Candida species, especially when receiving broad-spectrum antibacterials. The question of which antifungal agent to choose has become more complex as the development of new drugs raises promising expectations. Until the 1980s therapy for invasive candidiasis was limited to amphotericin B, but with the advent of new antifungal agents, such as azoles and echinocandins, less toxic therapeutic options are possible and doors have opened towards prevention and optimised therapy in the case of documented candidiasis. Through the arrival of these new antifungal agents, a range of therapeutic strategies for the management of invasive candidiasis has been developed: antifungal prophylaxis, pre-emptive therapy, and empirical and definitive antifungal therapy. Each of these strategies has a specific target population, as defined by specific underlying conditions and/or individual risk factors. Antifungal prophylaxis, in order to prevent candidal infection, is based on the type of underlying diseases with a high risk for invasive candidiasis. Individual risk factors are not taken into account. Potential indications are bone marrow transplantation, liver transplantation, recurrent gastrointestinal perforations or leakages, and surgery for acute necrotising pancreatitis. Pre-emptive therapy is also a preventive strategy. It can be recommended on the basis of an individual risk profile including overt candidal colonisation. Empirical therapy is started in patients with a risk profile for invasive candidiasis. It is recommended in the presence of clinical signs of infection, deteriorating clinical parameters, or a clinical picture of infection not responding to antibacterials but in the absence of a clear causative pathogen. Definitive antifungal therapy is defined as therapy in patients with documented invasive infection. The main goal is to maintain a balance between optimal prevention and timely initiation of therapy on one hand, and to minimise selection pressure in order to avoid a shift towards less susceptible Candida species on the other hand.     

Antifungal agents used in systemic mycoses. Activity and therapeutic use

The development of the polyene antibiotic, amphotericin B, provided for the first time a drug which was clinically effective in many serious mycotic diseases. Unfortunately, it requires parenteral administration and is often toxic, factors which limit the total cumulative dose which can be given. Efforts to utilise combinations of amphotericin B with other agents were best realised with amphotericin B/flucytosine in cryptococcal meningitis, and to a lesser degree in systemic candidiasis. More recently, the introduction of new imidazoles has extended the range of applications of these drugs to fungal diseases. Two members of this group, miconazole and ketoconazole, are promising agents. Miconazole is a parenterally administered agent for patients acutely ill with candidiasis and other mycotic infections. It may be the drug of choice for Petriellidium boydii infections and it is an attractive alternative to amphotericin B for intrathecal administration to patients with fungal meningitis. Ketoconazole offers much less toxicity, the advantage of oral administration, and the possibility of indefinitely prolonged therapy. However, it does not attain high concentrations in either the urine or cerebrospinal fluid. With the imidazoles, we have entered a new era of antifungal therapy which may produce even better antifungal agents than those currently available.     

Fluconazole versus amphotericin B for the prevention of fungal infection in neutropenic patients with hematologic malignancy.

Effective prophylaxis against fungal infection is important in neutropenic patients with hematologic malignancies, but the best method remains unclear. We investigated the effectiveness of fungal prophylaxis with amphotericin B or fluconazole. We reviewed the data on fungal isolates, plasma (1-->3)-beta-D glucan (beta-D glucan) levels, febrile periods (the number of days with an axillary temperature > 38 degrees C), and the duration of an axillary temperature > 38 degrees C when the neutrophil count was < 500/microliter. Of the 124 patients studied, 57 had acute myelogenous leukemia, 19 had acute lymphoblastic leukemia, 18 had non-Hodgkin's lymphoma, six had chronic myeloid leukemia, three had adult T-cell leukemia, and five had chronic lymphocytic leukemia. There were no significant differences in clinical characteristics between the 70 patients treated with amphotericin B and the 54 patients given fluconazole. There was a significant decrease of fungal isolates (chi 2-test, p < 0.001), the plasma beta-D glucan level (Wilcoxon test, p = 0.0001), and the febrile period (t-test, p < 0.05) in the patients given fluconazole compared with those given amphotericin B. In neutropenic patients with hematologic malignancies, prophylaxis with fluconazole significantly decreased fungal isolation and other indicators of fungal infection when compared with amphotericin B. Fluconazole may therefore be more effective for fungal prophylaxis in these patients.