The present invention relates, generally, to oral osmotic drug delivery systems, methods of preparing same, and methods of using oral osmotic drug delivery systems to provide controlled delivery of a drug. The oral osmotic drug delivery systems include a drug layer, an osmotic layer, and an outer coating surrounding the drug layer and osmotic layer, where the outer coating includes at least one opening therein that is provided adjacent the drug layer. The composition (% fines), shape, and weight gain of the oral osmotic delivery systems may be modified in order to provide for optimized release of the drug contained therein.