An observation was made by the pain relieving effectofmorphinesulfatecontrolled-release tablets(MS Contin) given by rectal route to 30 advanced cancerpatients in their final stage.
The FDA's warning letters notified the companies they may be subject to legal action if they do not stop manufacturing and distributing "prescription unapproved products" that include high-concentrate morphinesulfate oral solutions and immediate-release tablets containing morphinesulfate, hydromorphone or oxycodone.