Zudena 100 mg contains udenafil, which is used to treat erectile dysfunction (ED). Udenafil works by increasing blood flow to the penis, helping to achieve and maintain an erection during sexual stimulation. It usually starts to work within 30 to 60 minutes after taking it. The effects can last for several hours, allowing for flexibility in sexual activity. Always speak with a doctor before using Zudena 100 mg tablet to ensure it's safe for you, especially if you have other health conditions or are taking medications that could interact.