At intervals of five to nine days, healthy volunteers were given two 12.5-mg promethazine rectal suppositories, one 25-mg suppository, one 50-mg suppository, or 50 mg (10 mL) of promethazine oral ...

The pharmacokinetics of promethazine administered in oral syrup ... in terms of dose- normalized C max. [a] Phenergan 12.5-mg rectal suppository, Wyeth-Ayerst Laboratories, Radnor, PA, lot 9940524.