Feb 26, 2015 Promethazine is thought to potentiate the “high” from opioids. and promethazine to get “high” (Mattoo et al., 1997, 1999; Elwood, 2001; Peters et al., 2003, 2007). Consuming large quantities of these two drugs prolongs and .. Oechsler H, Verthein U. ;South Asian...