I have tinea versicolor. what effective drug should i use?

Topical anti fungal : Depending on the extension and location of the disease, you can use from Selenium Sulfide shampoo (like Selsun Blue) or Clotrimazole or terfinabine creams. Also oral antifungals can be taken for recalcitrant cases. You should expect that the skin discoloration may persist for months after treatment and resolution have occurred.