“Synchronic” (*1/2 out of four) was a dreary horror melodrama about two alcoholic paramedics (Anthony Mackie and Jamie Dornan) who encounter a series of horrific deaths linked to the title designer drug which they come to realize has a series of bizarre and hallucinatory side effects. Opens promisingly but grows more cerebral and slower and gradually falls apart before its pretentious climax. Mackie is strong as usual and provides film’s only real grit and heart.