Is Penegra as potent as Viagra? My current boyfriend takes penegra as he says that he as problems sometime in getting a erection quickly.Penegra is a Zydus Alidac product containing 50mg of Sildenafil Citrate equivalent to Sildenafil{i.e. in Penegra 50.Penegra 100 contains 100mg of Sildenafil}.He says that the contents are same as Viagra and that it is half the price of Viagra.He is taking Penegra 50 tablets{one tablet a hour before sex}.However after taking the tablet he sometimes complains of headache in the morning.Is that due to the tablet? On two occasions he couldnot get an erection even after taking the tablet an hour before.I am thinking of asking him to use Viagra. But before that I wanted to clear these doubts. Does Vaigra have the same contents as Penegra[i.e.Sildenafil].If so is it more potent than Penegra? Does it cause headache in morning? What is the preferred dosage of Viagra? Please help me in clearing up this doubts.

Summarized question: Do Viagra and Penegra have the same contents, power and dosage?