Ketoconazole

A risk-benefit assessment of the newer oral antifungal agents used to treat onychomycosis

The newer antifungal agents itraconazole, terbinafine and fluconazole have become available to treat onychomycosis over the last 10 years. During this time period these agents have superseded griseofulvin as the agent of choice for onychomycosis. Unlike griseofulvin, the new agents have a broad spectrum of action that includes dermatophytes, Candida species and nondermatophyte moulds. Each of the 3 oral antifungal agents, terbinafine, itraconazole and fluconazole, is effective against dermatophytes with relatively fewer data being available for the treatment of Candida species and nondermatophyte moulds. Itraconazole is effective against Candida onychomycosis. Terbinafine may be more effective against C. parapsilosis compared with C. albicans; furthermore with Candida species a higher dose of terbinafine or a longer duration of therapy may be required compared with the regimen for dermatophytes. The least amount of experience in treating onychomycosis is with fluconazole. Griseofulvin is not effective against Candida species or the nondermatophyte moulds. The main use of griseo-fulvin currently is to treat tinea capitis. Ketoconazole may be used by some to treat tinea versicolor with the dosage regimens being short and requiring the use of only a few doses. The preferred regimens for the 3 oral antimycotic agents are as follows: itraconazole - pulse therapy with the drug being administered for 1 week with 3 weeks off treatment between successive pulses; terbinafine - continuous once daily therapy; and fluconazole - once weekly treatment. The regimen for the treatment of dermatophyte onychomycosis is: itraconazole - 200mg twice daily for I week per month x 3 pulses; terbinafine - 250 mg/day for 12 weeks; or, fluconazole - 150 mg/wk until the abnormal-appearing nail plate has grown out, typically over a period of 9 to 18 months. For the 3 oral antifungal agents the more common adverse reactions pertain to the following systems, gastrointestinal (for example, nausea, gastrointestinal distress, diarrhoea, abdominal pain), cutaneous eruption, and CNS (for example, headache and malaise). Each of the new antifungal agents is more cost-effective than griseofulvin for the treatment of onychomycosis and is associated with high compliance, in part because of the shorter duration of therapy. The newer antifungal agents are generally well tolerated with drug interactions that are usually predictable.

Non-suppression of cortisol secretion by long term treatment with ketoconazole in patients with acute leukaemia

Ketoconazole, a potent antifungal agent, inhibits adrenal steroidogenesis in normal subjects during short term treatment. Since this drug is used in the long term prophylaxis of fungal infections in patients with haematological malignancies, we have investigated whether such patients have evidence of adrenocortical suppression. Six patients on long term prophylaxis with ketoconazole were given tetracosactrin stimulation tests. All patients had high basal cortisol concentrations, which increased further after administration of 25 IU of tetracosactrin. It is concluded that leukaemic patients receiving long term ketoconazole treatment do not have adrenocortical suppression. They may, in fact, have hyperstimulated adrenocortical function due to stress and hypovolaemia.

Modification of polymorphonuclear leucocyte function by imidazoles

The effect of five imidazole derivatives (metronidazole, tinidazole, clotrimazole, miconazole and ketoconazole) on human polymorphonuclear leucocytes (PMNL) was examined in vitro. Metronidazole and tinidazole had no apparent effect on either PMNL chemotactic response or PMNL fungal/bacterial killing. In contrast, clotrimazole, miconazole and ketoconazole inhibited PMNL chemotaxis. In addition, miconazole and ketoconazole were shown to depress the ability of PMNL to kill bacteria and fungi.

Ketoconazole treatment of nail infection in chronic mucocutaneous candidiasis

Chronic mucocutaneous candidiasis is an immunodeficiency disorder which has significant morbidity due to mucous membrane, skin and nail infection. Attempts at reconstitution of immunological abnormalities have had only limited success. Ketoconazole is a newly available oral antifungal agent with activity against candida species. Prolonged administration of ketoconazole to four children with chronic mucocutaneous candidiasis caused marked improvement at infected sites. Resolution of nail infections took up to 12 months.