Zudena 100 mg tablet (udanafil) is a medication used to treat erectile dysfunction. The duration of its effects can vary from person to person, but generally, the effects of a tablet of Zudena 100 mg can last for about 6 to 8 hours. It's important to follow your doctor's guidance on how to use it, including the recommended dosage and timing. If you have any specific concerns or side effects, consulting your healthcare provider is always the best approach.