Sildenafil citrate is the active component in the drug brand Fildena 100 purple pill. PDE-5 inhibitor sildenafil citrate treats erectile dysfunction (ED) in male patients. Fildena 100 empowers men to achieve and sustain erections that can reignite passion and intimacy. A sildenafil product with a high dosage, Fildena Double 200 is the active component. Men with severe or persistent ED are frequently prescribed one of the highest sildenafil doses available.