RxMed: Pharmaceutical Information - NIZORAL SHAMPOO In vitro studies suggest that the antifungal properties of ketoconazole may be related to its ability to impair the synthesis of ergosterol, a component of fungal and yeast cell membranes. Without the availability of this essential sterol, there are morphological alterations of the fungal and yeast cell membranes manifested as abnormal membranous inclusions between the cell wall and the plasma membrane. The inhibition of ergosterol synthesis has been attributed to interference with the reactions involved in the removal of the 14-a-methyl group of the precursor of ergosterol, lanosterol. Ketoconazole 2% shampoo causes minimal skin and scalp irritation. During clinical trials, 33 (3.7%) of 892 patients treated with the shampoo and 12 (3.6%) of 330 patients treated with placebo reported side effects. The adverse effects reported by patients treated with ketoconazole 2% shampoo consisted mainly of: greasy hair or scalp (1.2%); dry (brittle) hair or scalp (0.9%); irritation (0.5%); burning sensation and dryness (eyebrows) (0.2%). All other adverse experiences were reported with an incidence of 0.1%: exfoliative dermatitis; dandruff; irritation around mouth (acne perioralis); contact allergy; worsening of acne; burning sensation or pruritus (scalp); cosmetological disorder; hair loss; tiny pustules on scalp; dryness and itching of forehead and cheeks.
