Terbinafine hydrochloride is a more commonly used antifungal drug in clinical practice, which has a strong killing effect on ringworm and is more effective than itraconazole. How long it takes to have an effect depends on which diseases are being treated, for example, for ringworm, it is usually sufficient to take it orally for about 7-10 days. If you are treating nail fungus or fingernail infection, you need to take it for at least about 6 weeks. If it is for toenail infections, it needs to be taken for at least about 12 weeks. If you are treating ringworm of the head, you need to take it for at least 1 month. Terbinafine hydrochloride tablets are generally safe to take. If you take them for a long time, you should also have regular blood tests and liver and kidney tests, and you can continue to take them if there are no side effects.