There is sildenafil in Penegra. It is a medication that works well for treating male erectile dysfunction (ED). A guy with erectile dysfunction is unable to get and/or sustain an erection strong enough for sexual activity. Depending on your doctor's recommendation, you can take Penegra with or without food. You should take the tablet 30 to 60 minutes before engaging in sexual activity. While undergoing treatment, try to avoid or consume alcohol in moderation as it can cause vertigo. Avoid operating machinery or driving while receiving Penegra therapy.