What the hell is transient penile shrinkage?
Well let me start with a little anatomy and physiology. Arousal leads to reduced venous outflow from the penis (hence an erection). This process is primarily regulated by the parasympathetic nervous system. Viagra (sildenafil) works by increasing the amount of nitric oxide released in the penile veins (nitric oxide dilates blood vessels so the more they dilate the bigger the . . . effect). No one knows for sure but hypothetically stimulants produce vasoconstriction in penile vessels . . . as the caliber of these vessels shrink . . . the flaccid penis gets smaller. After the stimulant has cleared the bloodstream, the flaccid penis returns to its normal unaroused length.
Erection/Ejaculation is one of the few body functions where the parasympathetic/sympathetic nervous systems work in sequence to produce a particular effect. It's the only thing I remember well from anatomy was a professor telling us it was the Point (parasympathetic) and Shoot (sympathetic) process.
provigil is great for add...it barely has side effects and doens't affect sleep at all, anything else...
To date, nothing has proven to be as effective as stimulatns (Adderall, Dexedrine, Ritalin). Strattera certainly looks interesting and initial studies demonstrated comparable effects to stimulants but it is not 1st line for most psychiatrist unless there's some other reason to avoid stimulants. Provigil is NOT as effective as stimulants but is certainly superior to Wellbutrim for ADD symptoms. It does not carry an indication b/c Cephalon does not want to invest the money in clinical studies. Regardless, it carries the same caveat as Stattera . . . unless there's a particular contraindication . . . stimulants are the only 1st line drug therapies for ADD.
Edit to clarify 1st line drug therapy . . . not to ignore cognitive behavioral therapy.