In certain embodiments, the present invention is directed to a solid controlled release dosage form comprising: a core comprising a first portion of an opioid analgesic dispersed in a first matrix material comprising polyethylene oxide having an average molecular weight from about 300,000 to about 10,000,000; and a shell encasing the core and comprising a second portion of the opioid analgesic dispersed in a second matrix material comprising polyethylene oxide having an average molecular weight from about 1,000,000 to about 10,000,000.