Side effects associated with terbinafine 250 mg tablets include diarrhea, nausea and the inability to taste, according to RXList. Other potential side effects include fatigue, persistent coughing, chest pain and sores in the mouth.
As an ingredient in over-the-counter powders and creams, terbinafine treats minor fungal conditions like athlete's foot and jock itch. The 250 mg terbinafine hydrochloride tablets require a prescription and target more serious fungal infections in fingernails or toes, also called onychomycosis. Doctors prescribe terbinafine in its oral granule form to treat children with scalp infections, so long as they are at least four years old.
The standard regimen for treating fingernail onychomycosis involves taking one 250 mg dose each day for six weeks. Patients with toenail onychomycosis take the same daily dose but for 12 weeks. Before starting terbinafine regimens, patients should inform their doctors about all medications in use. This antifungal can interact with other antibiotics, blood thinners, heart rhythm regulators and beta blockers. Breastfeeding mothers should not use this medication.
Terbinafine hydrochloride is also sold as Lamisil. The antifungal works by disrupting production of squalene epoxidase, an enzyme critical for fungal growth. After treatment with terbinafine is complete, it can take weeks or months for healthy nails to grow and replace damaged nails.