Fildena 100 mg is used to treat erectile dysfunction. This drug is a powerful drug combined with the main ingredient of sildenafil. This medicine should be taken only once a day. This drug causes a sharp increase in blood flow to the muscles in the penis which helps in maintaining the erection action for a long time. You should take this medicine only once a day. The effect of this drug lasts for 4 to 6 hours after taking the drug.