Hi,I used to take Bentyl for the cramps too, my doctor recommended one 10mg tablet for my size (i'm 7 stone and just over 5 foot) although occasionally i would take two if the cramps were really bad.The only real effect I found was a negative one, the Bentyl made me feel really slow and i had to concentrate if i needed to do anything. I would feel quite woozy, and would put keys in the fridge and drinks in the door and suchlike.I found this would happen no matter what dose i took!!Eventually I gave up the Bentyl as if I had to rush out anywhere in the car there was no way I could drive!!!