All of the following drugs are effective in the treatment of pityriasis versicolor, except:

Ans. C. GriseofulvinPityriasis versicolor is caused by yeast=like microorganism Pityrosporum ovale. Pale, scaling macules develop insidiously over the skin of the chest and back in young adults. Tropical imidazole creams (miconazole, clotrimazole, econazole) applied once daily for 6 weeks or use of ketoconazole shampoo to wash the affected areas once daily for 5 days are usually sufficient. Older medicines such as 20% sodium thiosulfate solution and selenium disulphide shampoo are also effective, as is the oral itraconazole for 7 to 15 days.