Like other Fildena products, Fildena XXX likely contains sildenafil citrate, a PDE5 inhibitor. It works by relaxing the blood vessels in the penis, improving blood flow during sexual arousal and allowing an erection to be achieved and maintained. As with standard Fildena products, it would be effective when taken 30–60 minutes before sexual activity, and its effects typically last 4–6 hours. Always consult a healthcare provider before taking sildenafil-based medications, especially if you’re unsure about the formulation or dosage.