Codeine mechanism of action. . . . . . The precise mechanism of action of codeine is not known; however, like morphine, codeine . Guaifenesin works by loosening the mucus in the chest whereas codeine directly . Pharmacodynamics/Mechanism of action:This issue of Pediatric Pharmacotherapy will review the pharmacology of codeine and highlight recent publications of its use in children. . The dopamine rich areas of the brain are the ventral tegmental area, the nucleus . . indomethacin - mechanism ... more