Shares of Pain Therapeutics have been lopped in half as Big Pharma partner Pfizer has put Pain's Remoxy, its lead drug candidate, under review. Durect has plunged more than 35%, as its extended-release tech is used in the product. 

In this video, health-care analyst David Williamson picks up the pieces for investors and takes a closer look at the abuse-resistant painkiller space while discussing the future of Pain Therapeutics.