The active component of Zudena pills, a drug used to treat erectile dysfunction (ED) in men, is udenafil, a PDE5 inhibitor. It helps get and keep an erection by boosting blood flow to the penis during sexual stimulation. Zudena has a longer window of action than some other ED drugs; it usually begins to work within 30 to 60 minutes and can last for up to 12 hours.

Only when sexual activity is expected should it be taken, once day, with or without food. Dizziness, headache, flushing, and nasal congestion are typical adverse effects. Zudena should only be taken under a doctor's supervision because it is not appropriate for people with specific medical conditions or those taking blood pressure or nitrate drugs.