) is indicated for moderate to severe pain
which includes chronic severe disabling pain, particularly non-cancer pain which does not respond to milder analgesics. It is from the same family of morphine-type drugs, and carries the same risks and side effects. One of the issues of these medications is tolerance over time, meaning that the pain receptors in the body get used to the dose and need more to see the same effect. A multimodal pain relief-approach, including other adjuvant techniques such as relaxation, manipulation, accupuncture, and regular activity as tolerated can help gain quality of life for him.
Hope he feels better and this helps,
Mayo Clinic Rochester