Method of treating humans with opioid formulations having extended controlled release

A method for treating pain in humans for a time period of about 24 hours, comprising

• preparing a solid, controlled-release oral dosage form consisting of a plurality of inert pharmaceutical beads coated with an analgesically effective amount of an opioid analgesic or a mixture of opioid analgesics or a salt thereof, said inert pharmaceutical beads overcoated with a controlled release coating, wherein the dissolution rate in-vitro of the dosage form when measured by the USP Paddle Method of U.S. Pharmacopeia XXII(1990) at 100 rpm at 900 ml aqueous buffer at 1.6 and 7.2 pH and 37.degree. C. from about 16.8% to about 42.5% (by wt) opioid release after 1 hour, from about 25% to about 65% (by wt) opioid released after 2 hours, from about 45% to about 85% (by wt) opioid released after 4 hours, and greater than about 60% (by wt) opioid release after 8 hours, the in-vitro release rate being substantially independent of pH in that a difference, at any given time, between an amount of opioid released at one pH and an amount released at any other pH, when measured in-vitro using the USP Paddle Method of U.S. Pharmacopeia XXII (1990) at 100 rpm in 900 ml aqueous buffer, is no greater than 10%, the in-vitro release rate being chosen such that the peak plasma level of said opioid obtained in-vivo occurs from about 2 to about 8 hours after administration of the dosage form;
• said dosage form providing an extended duration of therapeutic effect of about 24 hours;
• and
• administering said dosage form to a human patient at a dosing interval of about 24 hours.