598922 Gastric retentive dosage forms for extended release of acetaminophen or for both immediate and extended release of acetaminophen are described. The dosage forms allow effective pain relief upon once- or twice-daily dosing. Treatment using the dosage forms and methods of making the dosage forms are also described. The dosage forms comprise a extended release (ER) layer comprising a first dose of acetaminophen dispersed in a polymeric matrix (polyether is exemplified) wherein the polymeric matrix is comprised of at least one hydrophilic polymer having a molecular weight of 900,000 Daltons, which swells upon imbibition of fluid to a size sufficient to promote gastric retention, and wherein the first dose of acetaminophen is released over a time period of about 8 to 9 hours in vitro.
