Antifungal agents used for deep-seated mycotic infections

Effect of biphenyl dimethyl dicarboxylate on the cellular and nonspecific immunosuppressions by ketoconazole in mice

The effect of biphenyl dimethyl dicarboxylate (PMC) on the cellular and nonspecific immunosuppressions by ketoconazole (KCZ) was investigated in ICR mice. PMC at a dose of 6 mg/kg was administered orally to mice daily for 14 consecutive days. KCZ was suspended in RPMI 1640 medium and orally administered at 160 mg/kg/day 2 hrs after the administration of PMC. Immune responses of the delayed-type hypersensitivity (DTH) reaction to sheep red blood cells (SRBC), phagocytic activity and natural killer (NK) cell activity were evaluated. DTH reaction to SRBC was enhanced to normal level by the combination of PMC and KCZ, compared with treatment of KCZ alone. In the combination of PMC and KCZ, as compared with the treatment of KCZ alone, there were also significant increases in activities of natural killer (NK) cells and phagocytes along with circulating leukocytes. These findings indicate that PMC shows a significant restoration from the immunotoxic status induced by KCZ.

Effect of biphenyl dimethyl dicarboxylate on the humoral immunosuppression by ketoconazole in mice

The present study was undertaken to investigate the effect of biphenyl dimethyl dicarboxylate (PMC) on the humoral immunosuppression by ketoconazole (KCZ) in ICR mice. PMC at a dose of 6 mg/kg was administered orally to mice daily for 14 consecutive days. KCZ was suspended in RPMI 1640 medium and orally administered at 160 mg/kg/day 2 hrs after the administration of PMC. Mice were immunized and challenged with sheep red blood cells (SRBC). The results of the present study are summarized as follows; a gain of body weight and relative weights of spleen and liver were significantly increased by combination of PMC and KCZ, as compared with those in mice treated with KCZ alone. Splenic plaque forming cells (PFC) and hemagglutination (HA) titers to SRBC were greatly enhanced by the combination of PMC and KCZ, compared with treatment of KCZ alone. The elevation of serum glutamicpyruvic transaminase (S-GPT) and total protein levels caused by KCZ were reduced to normal level by the combination of PMC and KCZ. In addition, lower serum albumin and A/G ratio were also increased to normal level. These findings indicate that PMC has a protective effect against KCZ-induced humoral immunosuppression.

Antifungal agents. Part I. Amphotericin B preparations and flucytosine

Traditionally, amphotericin B has been the cornerstone of antifungal treatment. Toxicity, however, is a major dose-limiting factor of amphotericin B deoxycholate. Nevertheless, it continues to have a major role in the treatment of deep-seated mycotic infections. Recently, less nephrotic lipid formulations, including amphotericin B lipid complex, amphotericin B cholesteryl sulfate, and liposomal amphotericin B, have been introduced. The pharmacologic properties, main indications, recommended dosages, related costs, and adverse effects of these various preparations are summarized in this review. Orally administered flucytosine is useful in certain infections, particularly cryptococcal meningitis, but it should be used with caution in patients with renal insufficiency.

Oropharyngeal candidiasis: a review of its clinical spectrum and current therapies

With the increased use of antibiotics and immunosuppressive agents, oropharyngeal candidiasis is becoming more common. This infection is also associated with such advances in medical management as chemotherapy and organ transplantation and with human immunodeficiency virus infection. Various topical and systemic agents are available to treat patients with candidiasis, but optimal management can be elusive. Treatment of uncomplicated oropharyngeal candidiasis in the immunocompetent patient involves selecting a particular formulation of a topical medication based on oral conditions, length of contact time, and taste, texture, and cost of the medication. Treatment of severe oropharyngeal candidiasis, particularly in patients with a compromised immune system, is often more difficult, and relapses are common. Reports of resistance to systemic agents, particularly in patients needing recurrent therapy, are increasing. Amphotericin B, long used as an intravenous agent, is now available as an oral suspension that may offer therapeutic benefits comparable to those of systemic therapy without the toxicity associated with systemic absorption.

Itraconazole for the treatment of cryptococcosis in cats

Itraconazole was used in 35 cats with cryptococcosis. Treatment response was determined by comparing clinical signs before, during, and after treatment. It could not be evaluated in 7 cats because they died during treatment from causes unrelated to cryptococcosis. Of the remaining 28 cats, treatment response was classified as success in 16 cats (57%), as improvement in 8 cats (29%), and as a failure in 4 (14%). The failures were due to death or euthanasia from drug toxicity (1 cat), progressive fungal disease (2 cats), and relapse 1 year after treatment (1 cat). The cats that improved did not undergo a 1-year posttreatment evaluation because they were lost to follow-up (3 cats), died or were euthanatized for other reasons (4 cats), or had a noncompliant owner (1 cat). For the 16 cats in which treatment was successful, the median itraconazole dose was 13.8 mg/kg body weight daily (range, 10.9 to 26.7 mg/kg/d), and the median duration of treatment was 8.5 months (range, 4 to 16 months). Five of these cats had previously been treated unsuccessfully with ketoconazole.

Rapid intravenous infusion of amphotericin B: a pilot study

PURPOSE

The administration of amphotericin B in the conventional prolonged infusion over 4 to 6 hours is complicated by the acute toxicities of fevers and chills in 50% to 90% of patients and the chronic toxicities of increased creatinine levels and hypokalemia in 60% to 80% of patients. To determine the safety and toxicity of rapid infusions, we conducted a prospective, nonrandomized study in patients with clinical indications for antifungal therapy.

PATIENTS AND METHODS

Twenty-five granulocytopenic adults with acute leukemia and myelodysplastic syndromes were enrolled in a phase I trial using four sequentially shorter infusion durations: a standard infusion over 4 hours (n = 3) and shortened infusion durations at 3 hours (n = 3), 2 hours (n = 4), and 1 hour (n = 15). Toxicity was assessed by daily examinations of study subjects by one of the study investigators, by documentation of all infusion-related fevers and chills, and by daily monitoring of serum levels of creatinine, potassium, magnesium, and aspartate aminotransferase.

RESULTS

Temperatures greater than 38 degrees C occurred in 16 of 25 (64%) patients, but only two had temperatures exceeding 40 degrees C. Chills were observed in 13 of 25 (56%) patients, but only one had severe symptoms. Serum creatinine increased more than 0.5 mg/dL (44.20 mumol/L) above the pretreatment baseline in 17 of 25 (68%) patients, and the absolute creatinine level was greater than or equal to 2.0 mg/dL (176.8 mumol/L) in 10 of 25 (40%) patients. Serum potassium levels dropped below the normal limit of 3.5 mEq/L (3.5 mmol/L) in all patients, but no patient had potassium levels below 2.5 mEq/L (2.5 mmol/L). Intravenous potassium supplementation was administered to all patients and exceeded 100 mEq/d in 12 of 25 (48%) patients.

CONCLUSIONS

Rapid infusions of amphotericin B are safe, are associated with similar toxicity as prolonged infusions, and facilitate inpatient care by decreasing nursing time needed for administration and minimizing scheduling conflicts with other necessary intravenous medications. Shorter infusions also facilitate outpatient and home administration of amphotericin B.

Itraconazole in antifungal therapy

OBJECTIVE

This overview compares and contrasts the pharmacotherapy of itraconazole with that of other antifungal agents.

DATA SOURCES

Primary literature on itraconazole was identified through a medical literature search from 1976 through 1991. This search included journal articles, abstracts, conference proceedings, and reports of animal and human research published in the English language.

STUDY SELECTION

All primary literature was reviewed regardless of the study design or outcome. Literature evaluations of efficacy were ranked using a literature rating scale (Dalen JE, Hirsh J. Arch Intern Med 1986;146:462-72), which was slightly modified to include case reports and observations.

DATA EXTRACTION

All data were collected and represented with a primary focus on itraconazole's mechanism of action, pharmacokinetics, clinical efficacy in systemic mycotic infections, drug interactions, and adverse reactions. All articles were referenced in the final data presentation unless grouped data had been accurately reviewed and published.

DATA SYNTHESIS

Despite the paucity of controlled comparative trials with itraconazole in patients with deep mycoses, results on efficacy are encouraging. It is still unclear what role itraconazole will have in the prophylaxis of fungal infections in immunocompromised hosts. The favorable pharmacokinetic profile permits once- or twice-daily administration and itraconazole appears to be safe and well tolerated.

CONCLUSIONS

Itraconazole should prove to be a useful replacement for ketoconazole on hospital formularies. This recommendation is based on itraconazole's greater apparent safety and efficacy. Reevaluation of this agent will be necessary upon the release of newer imidazoles and triazoles.

Antifungal agents used for deep-seated mycotic infections

The increased use of immunosuppressive regimens in organ transplantation and in the treatment of malignant lesions and the epidemic of acquired immunodeficiency syndrome (AIDS) are major reasons for the greater prevalence of fungal infections seen in clinical practice during the past decade. The traditional cornerstone of antifungal treatment, amphotericin B, continues to play a major role in deep-seated mycotic infections. The indications for intravenously administered miconazole have become limited. Orally administered flucytosine remains useful in certain infections, particularly cryptococcal meningitis. The new orally administered antifungal agents ketoconazole and fluconazole have been approved for clinical use and have supplanted amphotericin B in certain situations. Investigational antifungal agents, including liposomal amphotericin B, itraconazole, and saperconazole, hold promise for the future. Active investigation in the development of new antifungal agents is expected to continue.

Recently described feline dermatoses

This article discusses the etiology, clinical signs, diagnosis, and treatment of several diseases. Feline immunodeficiency, virus infection, cryptococcosis, dermatophyte pseudomycetomas, demodicosis, Sézary-like syndrome, and discoid lupus erythematosus in cats are reviewed.

New therapeutic agents in veterinary dermatology

The rapid development of therapeutic agents will continue to provide veterinarians with new options in treating dermatologic disease. However, we must not overlook the possibility of new applications for older drugs. Ideally, before a drug can be recommended for routine use, it should be evaluated for safety and efficacy using unbiased scientific methods. Unfortunately, this type of testing is expensive and may take years to complete. Veterinarians faced with managing a difficult skin disease may have to make decisions based on anecdotal information or case reports. The importance of good client communication cannot be overemphasized. The veterinarian must explain the benefits and risks of each therapeutic option. A written informed consent statement is advisable when using a drug in a manner not approved by the FDA.

Cryptococcosis in a renal unit

Cryptococcosis is a known opportunistic infection in immunosuppressed hosts. We report our experience of all cases presenting to our Department between December 1975 and September 1988. Eight post-renal transplant patients and three systemic lupus erythematosus (SLE) patients were affected. All were receiving treatment with steroids, in association with either azathioprine or cyclosporin. The diagnosis of cryptococcal meningitis was initially based on a positive cerebrospinal fluid (CSF) cryptococcal antigen, by latex agglutination test, and subsequently confirmed by cultures. Common clinical presentations, in descending order of frequency, included headaches, fever, mental confusion, epilepsy and papilloedema. Meningism was not a prominent feature. CT brain scans were obtained in eight patients and one showed a focal lesion and one showed cerebral atrophy. Four patients also had an abnormal chest X-ray (CXR) and one had disseminated cryptococcosis. Amphotericin and 5-fluorocytosine were the mainstay of therapy, although ketoconazole alone was subsequently used in three selected patients with cure. Four early deaths occurred in patients with delayed diagnosis and treatment, usually in association with other severe concurrent infections. We conclude that awareness of cryptococcosis is essential in immunocompromised hosts presenting with headache with, or without, mental confusion or fever.

Randomized, double-blind trial of 1- versus 4-hour amphotericin B infusion durations

We conducted a randomized, double-blind trial of 1- versus 4-h infusions of amphotericin B to determine whether there was any difference in infusion-related toxicity. A total of 128 maintenance infusions in 12 patients were studied; 62 were randomized to 1-h infusions (group A) and 66 were randomized to 4-h infusions (group B). We found no significant differences between patients in groups A and B in mean temperature, pulse, or systolic or diastolic blood pressure measured during the infusions. At a significant level of 0.05, the power to detect a mean difference in temperature of 2 degrees C, a pulse difference of 20 beats per min, a decrease in diastolic blood pressure of 10 mm Hg, or a decrease in systolic blood pressure of 20 mm Hg was 0.95. Rigors and chills were noted in 15 of 62 (24.1%) infusions in group A patients and 12 of 66 (18.1%) infusions in group B patients (P = 0.40). Meperidine was required because of severe persistent rigors in 6 of 62 (9.6%) infusions in group A patients and 6 of 66 (8.9%) infusions in group B patients (P = 0.91). An increase in temperature was noted in five (8%) of the group A infusions and seven (10.6%) of the group B infusions (P = 0.63). The mean time to onset of rigors, an increase in temperature, and an increase in pulse occurred significantly earlier in group A than in group B patients (P = 0.02 for all comparisons). We conclude that there is no difference in the incidence or severity of the infusion-related toxicity of amphotericin B with a 1-h infusion rate compared with a 4-h infusion rate. However, the onset of infusion-related toxicity occurs significantly earlier with a 1-h infusion.

Imidazoles and triazoles in antifungal therapy

Fungal infections range from superficial mycoses involving skin or mucous membranes to severe opportunistic infections that may be fatal. The selection of chemotherapeutic agents useful for the treatment of fungal infections includes many topical or systemic imidazoles and triazoles. This overview compares and contrasts the pharmacology and therapeutic use of these agents. This review will focus primarily on these agents' mechanism of action, pharmacokinetics, clinical studies, and adverse reactions.

Chronic cavitary histoplasmosis. Failure of oral treatment with ketoconazole

Ketoconazole appears to be a safe drug in the treatment of chronic cavitary histoplasmosis. Primary failure and relapse have been described, requiring amphotericin B, even after long therapy with ketoconazole. Four typical cases are presented. We caution about such potential failures and stress the importance of close observation of patients begun on therapy with ketoconazole for chronic cavitary histoplasmosis.