It contains sildenafil citrate, which belongs to a class of drugs known as phosphodiesterase type 5 (PDE5) inhibitors. Fildena 100 works by increasing blood flow to the penis during sexual stimulation, thus helping men achieve and maintain an erection.

It's important to note that Fildena 100 should be taken as directed by a healthcare professional, typically about 30 minutes to 1 hour before sexual activity. The effects of the medication can last for up to 4-6 hours.

As with any medication, Fildena 100 may cause side effects such as headache, dizziness, flushing, nasal congestion, or upset stomach. It's essential to consult with a doctor before using Fildena 100, especially if you have any underlying health conditions or are taking other medications.