Oxybutynin
"From day 2 of taking this medication I suffered all the major side effects you are told about plus the ones you have to search for, the worst being a permanent headache and wanting to sleep constantly.  After 2 weeks of use my pharmacist told me to stop taking the tablets, this was over a week ago and the side effects still persist, have had to visit my doctor who doesn't know the half life of this medicine (it was prescribed by my surgeon). I have had to have blood and urine tests and won't know what damage has been done until I get the results back.  I can't even drive until the symptoms settle."