Modafinil
"I put off taking Modafanil until I used my cpap for 1 month as instructed by my doctor. I have complex sleep apnea, both obstructive & central & a circadian rhythm disorder, my clock is totally backwards, could be considered sleep shift work disorder but I haven't worked for a few years due to this & other medical issues. I've been doing a lot better but the sleep is the major issue. I tried modafinil 50mg, nothing. I then went to 100mg, nothing. I also tried 50 twice a day, nothing. After about 6 days I started experiencing EXTREME gastrointestinal pains, bloating & distension. I looked pregnant & could barely move because of the pain. I could not pass gas either. It was terrible. I was really disappointed as I heard good reviews here"