Treatments and drugs. Antifungal medications that can be taken by mouth are used to treat ringworm of the scalp. The medications most commonly prescribed include griseofulvin (Grifulvin V, Gris-Peg) and terbinafine (Lamisil). Your child might need to take one of these medications for six weeks or more.Your doctor might recommend that you also wash your child's hair with a prescription-strength medicated shampoo.he medications most commonly prescribed include griseofulvin (Grifulvin V, Gris-Peg) and terbinafine (Lamisil). Your child might need to take one of these medications for six weeks or more. Your doctor might recommend that you also wash your child's hair with a prescription-strength medicated shampoo.