Dyspnea possibly associated with controlled-release morphine sulfate tablets

Morphine sulfate in controlled-release tablet form is a relatively new oral preparation being used for the relief of chronic severe pain, such as that related to cancer. A patient with adenocarcinoma of the prostate with bone metastases experienced dyspnea possibly related to the ingestion of these tablets. Discontinuing the drug quickly resulted in disappearance of the dyspnea. The respiratory effects of morphine and the particular risks posed to the elderly patient are discussed.