Fungal infections, imidazole

Miconazole is an imidazole antifungal agent used as miconazole base or miconazole nitrate for the treatment of superficial candidiasis and of skin infections dermato-phytosis and pityriasis versicolor. The drug has also been given intravenously by infusion for the treatment of disseminated fungal infections. Miconazole can be given by mouth in a dose of 120-240 mg, as oral gel four times daily after food, for... 

Clotrimazole is an imidazole antifungal agent indicated for the treatment of fungal infections caused by Candida albicans. The administration of clotrimazole would be of no use in the treatment of infections caused by Chlamydia trachomatis, Neisseria gonorrhoea, Staphylcoccus aureus and Streptococcus pneumoniae. 

Some imidazole derivatives have turned out to be extremely beneficial for treating fungal infections. They are ketoconazole, miconazole, clotrimazole, econazole, butoconazole, and others. 

Fungal infections superficial dermatophyte or Candida infections purely involving the skin can be treated with a topical imidazole (e.g. clotrimazole, miconazole). Pityriasis versicolor, a yeast infection, primarily involves the trunk m young adults it responds poorly to imidazoles but topical terbinafine or selenium sulphide preparations are effective severe infection may require systemic itraconazole. Invasion of hair or nails by a dermatophyte or a deep mycosis requires systemic therapy terbinafine is the most effective drug. Terbinafine and griseo-fulvin are ineffective against yeasts, for which itraconazole is an alternative. Itraconazole can be used in weekly pulses each month for 3-4 months it is less effective against dermatophytes than terbinafine. 

Other imidazole derivatives include clotrimazole (Fig. 10.22B), miconazole (Fig. 10.22C) and econazole (Fig. 10.22D), all of which possess a broad antimycotic spectrum with some antibacterial activity and are used topically. Miconazole is used topically but can also be administered by intravenous or intrathecal injection in the treatment of severe systemic or meningeal fungal infections. Newer imidazoles are (a) ketoconazole (Fig. 10.22E),... 

Since their discovery in the late 1960s several compounds from the chemical class of 1-substituted imidazoles and 1,2,4-triazoles have been developed and successfully used for the control of plant diseases and for the treatment of human fungal infections. The first commercial triazole compound was triadimefon ( 1J, introduced by Bayer in 1973 for the control of powdery mildew, rusts, and seed-borne diseases of cereals. Since that time many other so called "azole-fungicides" have been introduced into crop protection (2) and others are still being developed. 

Fungal infections are among the most conunon causes of skin disease in the United States, and numerous effective topical and oral antifungal agents have been developed. Griseofulvin, topical and oral imidazoles, triazoles, and allylamines are the most effective agents available... 

Some of imidazoles and triazoles are the potential inhibitors of 14-demethylase, a key enzyme in the sterol biosynthesis pathway, thus directly interfere with cell wall biosynthesis in Leishmania. Fluconazole, a triazole antifungal drug used in the treatment and prevention of superficial and systemic fungal infections, has been used for the treatment of L. major in Old World. Similarly, ketoconazole has been used in the New World against L. panamensis and L. mexicana. Itraconazole... 

---