Sildenafil Citrate in Suhagra 25 mg works by increasing blood flow to the penis during sexual stimulation. This helps men with ED achieve and maintain an erection suitable for sexual activity. Suhagra 25 mg should be taken as directed by a healthcare provider. It is usually taken on an as-needed basis, about 30 minutes to 1 hour before anticipated sexual activity. It should not be taken more than once a day.