Terbinafine hydrochloride 250 milligram tablets treat symptoms of toenail and fingernail onychomycosis, a fungal infection caused by dermatophytes, states DailyMed. Doctors prescribe one tablet daily for six weeks to treat infected fingernails and one tablet daily for 12 weeks to treat infected toenails. Terbinafine hydrochloride is the tablet's antifungal ingredient.
Clinical trials show terbinafine HCL tablets are about 70 percent effective in curing toenail onychomycosis, with approximately a 15 percent recurrence rate one year after finishing the therapy. For fingernail onychomycosis, the effective cure rate is about 79 percent, according to DailyMed. Some patients taking terbinafine HCL tablets experienced liver failure that was fatal or required liver transplants. The organ failed in individuals who had liver disease before taking the medication and in individuals with healthy livers. Patients with symptoms including nausea, vomiting, pale stools or dark urine should contact their doctors immediately.