Sildenafil citrate, the same active ingredient found in Viagra, is an ingredient in the drug Filagra, which is intended to treat erectile dysfunction (ED) in men. It helps men get and keep a hard erection by boosting blood flow to the penis during sexual stimulation. The effects of filagra can persist for four to six hours, and it is usually taken 30 to 60 minutes before engaging in sexual activity. Headache, flushing, nasal congestion, and lightheadedness are typical adverse effects. Before using it, it's crucial to speak with a doctor to assure safety because it shouldn't be combined with nitrates or certain heart drugs.