A dual release oral dosage system/dosage form comprising an immediate release component/composition and a delayed release component/composition is described. Each of the immediate release component/composition and delayed release component/composition comprising (a) one or more of doxylamine and a pharmaceutically acceptable salt thereof and (b) one or more of (i) pyridoxine, (ii) a metabolite thereof selected from pyridoxine phosphate, pyridoxal, pyridoxal 5-phosphate, pyridoxamine, and pyridoxamine 5-phosphate, (iii) a pharmaceutically acceptable ester of (i) or (ii), and (iv) a pharmaceutically acceptable salt of any of (i)-(iii). The dual release oral dosage system/dosage form exhibits an improved pharmacokinetic profile relative to the current Diclectin® formulation and is useful for example for the alleviation of the symptoms of nausea and vomiting, for example in the case of nausea and vomiting in pregnancy (NVP).
