Malegra 25 mg contains sildenafil citrate, a PDE5 inhibitor used to treat erectile dysfunction. Side effects occur because the drug doesn’t act only in the *****—it affects blood vessels and circulation throughout the body. Here’s why and how: 1. Vasodilation (Widening of Blood Vessels) Sildenafil relaxes smooth muscles in blood vessels to improve blood flow to the *****. However, it can also affect other areas: Head → headache or flushing Nose → nasal congestion Digestive system → indigestion 2. Changes in Blood Pressure Because it dilates blood vessels, it can lower blood pressure slightly, which may cause: Dizziness Lightheadedness Fainting (rare) 3. Interaction with Other Medications Sildenafil can interact with nitrates or alpha-blockers, causing dangerous drops in blood pressure. 4. Effects on Vision and Hearing Rarely, the drug can affect enzymes in the retina or inner ear, leading to: Temporary blue-tinted vision Increased sensitivity to light Sudden hearing loss (very rare) 5. Individual Sensitivity Age, liver or kidney function, heart health, and other medications influence how the body processes sildenafil, which can make side effects more likely. In short, Malegra 25 mg causes side effects because it affects blood vessels and circulation throughout the body, not just in the *****. Most side effects are mild and temporary, but serious effects are possible in susceptible individuals.