Zudena 100 mg contains avanafil, which is primarily used to treat erectile dysfunction (ED). It is not typically used as a preventative measure but rather taken as needed before sexual activity. Zudena 100 mg tablet is usually taken about 15 to 30 minutes before anticipated sexual activity. It is not intended for daily or preventative use. The medication works by increasing blood flow to the penis during sexual stimulation, but it requires that stimulation to be effective. Always consult a healthcare provider for personalized advice, especially if you are considering its use for purposes other than treating ED.