Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. for your first question, yes there is a lot of difference between 50 mg and 100 mg as taking 100 mg would be double the does and it will stay in body for longer period and will have double the effects and side effects both. For your second question, these tablets were made to help people effected by erectile dysfunction they are not made for normal individuals to use, using them while you do not need them may exacerbate the normal phenomenon and you might end up in having very prolonged and painful erection. For your third question, no Viagra has no direct effect on the orgasm of women, an average female would take 10-12 minutes to reach an orgasm so using Viagra would lead to prolong erection and prolonged intercourse and that would make a women orgasm. Hope I have answered your query. Let me know if I can assist you further.