I take 75 mg of effexor in the a.m. and 37.5 at night. I suffer from low libido and an inability to maintain a strong erection. I have a rx for Viagar 50 which didn t work the first time I took it. My questions,,,,,if I eliminate the 37.5 nightime effexor would it help with the ed problem? Or should I try reducing the a.m. dose by half while still taking the nightime dose? Finally, could an increase to 100 mg of the Viagra help? MD