Antifungal chemotherapy

serious underlying defect in host defence, such as neutropenia or immunosuppression. Their distribution is world-wide. Cryptococcosis, an infection caused by the yeast Cryptococcus neoformans, fits uncomfortably into this classification. It is a pathogen of the respiratory system and in some parts of the world causes disease in previously healthy people, but in other areas it causes an infection of immunosuppressed patients with conditions that are associated with defective T-Iymphocyte function. Ancillary measures Although there are examples of fungal infections which resolve without intervention, such as candidaemia, treatment is usually necessary. To achieve the best results it is important to consider and, if possible, alter host factors which may have contributed to fungal invasion. For instance, the regular cleaning of dentures with antifungal solutions may be a necessary adjunct to the treatment of oral thrush. In other circumstances, the alteration of predisposing factors in the host may be impracticable or complicated. Transfusions of white cells are theoretically beneficial in neutropenic patients, but their administration in conjunction with that of amphotericin B by the intravenous route is believed by some investigators to precipitate a condition that is similar to "shock lung".' This interpretation of events has been contested because many of these patients also have a concomitant septicaemia caused by Gram-negative bacteria. Antifungal drugs The main antifungal compounds include members of two large families of drugs, the polyenes and the imidazoles. In addition, there exists a larger group of unrelated substances which may be used in treatment. Polyene antifungal agents The polyenes are a group of macrolide drugs which include amphotericin B, nystatin and