The following drug is effective in treatment of ptyriasis versicolor –
Treatment of P. versicolor

Systemic → Ketoconazole, Fluconazole, Itraconazole.
Topical → Azoles (clotrimazole, econazole, micronazole, ketoconazole), selenium sulfide, sodium thiosulphate, whitfield's ointment (3% salicylic acid + 6% benzoic acid).
Ketoconazole
Metronidazole
Griseofulvin
Chloroquine