I take morphine in 20mg tablet form but prefers Codeine instead. He used to take codeine phosphate but it got changed to morphine a couple of months ago. Swim thought that the morphine would be better but after taking some of his old codeine tablets I think the codeine gives better pain relief as well as giving a better buzz. Maybe it's the poor bioavailability of taking morphine orally? I would like to know the difference between Dyhydrocodeine and Codeine Phosphate before asking the G.P for advice.