I recently switched my prescription from a local pharmacy to a mail-in one, and they utilize a different brand of generic Ambien (Zolpidem). After now taking 7-8 of these pills I feel they are dramatically different - or even possibly have no impact - as compared to my previous generic. (Ambien is for insomnia, and helps a person fall asleep). I am wondering if there is either something wrong with these particular pills, or if the inactive agents might interact with something else I take, or perhaps something else going on? (I had one last older pill, took it, and it worked so there is definitely a very noticeable difference). Does anyone have any suggestions or thoughts about what could be causing this reduction in efficacy? I have major problems with sleeping and travel insomnia and now have a bottle of 80+ pills that may not work... Help! Thank you in advance for your insight.