Fildena 25 mg is marketed as containing sildenafil citrate 25 mg, a PDE5 inhibitor used to treat erectile dysfunction (ED). Sildenafil increases blood flow to the penis during sexual stimulation, helping achieve and maintain an erection. It does not directly increase sexual desire. For sildenafil, 50 mg is generally the standard starting dose, while 25 mg may be used when a lower dose is appropriate—for example, because of side effects, certain medical conditions, age, or interactions with other medicines. The maximum recommended dose is 100 mg, and sildenafil should be taken no more than once in 24 hours.