The effects of Zudena 100 mg can last for up to 24 hours after ingestion. This prolonged duration of action allows for greater flexibility in timing sexual activity compared to other ED medications. Zudena 100 mg is typically taken orally, about 30 minutes to 1 hour before sexual activity. The onset of action may vary between individuals, but it is generally recommended to take udenafil on an empty stomach for optimal absorption.