Maybe it was a case of opening-night jitters. Maybe the show needed a few more rehearsals, as recurrent flubbed lines seemed to indicate. Whatever, Frank Merle’s intelligent, well-paced staging of Michael Gazzo’s seminal 1955 drama–the first postwar Broadway play to deal with drug addiction–never achieved the tragic scope it should have. It wasn’t for lack of talent. The production features such off-Loop heavy hitters as the usually rock-solid Jeremy Glickstein as the protagonist, a Korean war POW whose hospital-induced morphine habit nearly destroys his family and leaves him deeply in debt to three thuggish pushers. This is the most even, convincing work I’ve seen from Merle to date; still, his strong cast only fleetingly found the script’s life-and-death stakes. But considering how they nailed the final few scenes, this show may simply need another week to dazzle. Through 7/16: Fri-Sat 8:30 PM, Sun 7 PM. Raven Theatre, 6157 N. Clark, 773-338-2177. $12-$15.