The efficacy and tolerability of controlled-release dihydrocodeine tablets and combination dextropropoxyphene/paracetamol tablets in patients with severe osteoarthritis of the hips.

A double-blind, parallel group study was undertaken in general practice to compare the efficacy of and tolerability to controlled-release (CR) dihydrocodeine tablets and combination dextropropoxyphene/paracetamol tablets in patients with severe osteoarthritis of the hip(s). Eighty-six patients were randomly allocated to receive either CR dihydrocodeine (60 mg) tablets (1 tablet twice daily to 2 tablets daily) or combination dextropropoxyphene (32.5 mg)/paracetamol (325 mg) tablets (2 tablets 3-times daily to 2 tablets 4-times daily) for a period of 2 weeks. Patients recorded in a diary card 4 times a day the severity of their pain and each morning whether or not they woke during the night due to pain in their hip(s). On entry to the study, after the first week's treatment and at the final visit another week later, the investigator assessed the patient's severity of pain on passive movement of the hip and also noted the severity of any volunteered symptoms or side-effects. After 2-weeks' treatment, pain on passive movement of the hip joint was statistically significantly less severe on CR dihydrocodeine than on dextropropoxyphene/paracetamol (p = 0.02). Nausea and vomiting were more pronounced in the dihydrocodeine than in the dextropropoxyphene/paracetamol group after the first week's treatment but by the end of the study there was no significant treatment difference in any of the volunteered side-effects. Patients on CR dihydrocodeine developed some constipation as expected and the dextropropoxyphene/paracetamol patients suffered from impaired concentration. More patients withdrew on CR dihydrocodeine than on dextropropoxyphene/paracetamol but these withdrawals tended to occur early in the trial just after initiating therapy. Tolerance in terms of withdrawals or side-effect profile did not appear to the dosage of each preparation administered. It is concluded that after 2-weeks' treatment CR dihydrocodeine provided superior analgesia to dextropropoxyphene/paracetamol with no difference in side-effects. Furthermore, CR dihydrocodeine has the advantage of twice rather than 3 or 4-times daily dosing.