Zenegra 100 Tablet contains Sildenafil 100 mg, a selective phosphodiesterase type 5 (PDE5) inhibitor indicated for the treatment of erectile dysfunction (ED) in adult men. Sildenafil facilitates penile erection by enhancing the effects of nitric oxide, a natural chemical that relaxes muscles in the corpus cavernosum, thereby increasing blood flow to the penis during sexual stimulation. This medication should be taken approximately 30 to 60 minutes before anticipated sexual activity, with its effects lasting up to 4-5 hours. Zenegra 100 is not an aphrodisiac and requires sexual stimulation to be effective. It is contraindicated in patients using nitrates or nitric oxide donors due to the risk of severe hypotension. Caution is advised in individuals with cardiovascular disease, hepatic or renal impairment, and those taking alpha-blockers or other antihypertensive agents. Common side effects may include headache, flushing, dyspepsia, nasal congestion, dizziness, and visual disturbances. Patients experiencing sudden vision loss, hearing impairment, or prolonged erections lasting more than 4 hours should seek immediate medical attention. Zenegra 100 should be used under medical supervision, with dosage adjustments based on efficacy and tolerability. It is not recommended for use in women or pediatric patients.