Alprazolam/'Xanax'- Goes fairly well with codeine, I reccomend .5-1mg Except now tolerant to benzo's. It provides a great deal far more sedation than diazepam does, but seems to lack the muscle relaxant Qualities that make diazepam synergise with codeine so nicely. ten-14 hour 50 percent lifetime.Hope somebody finds this beneficial, and that some i