Normal-release oral morphine starting dose in cancer patients with pain

To evaluate whether the current European Association for Palliative Care recommendation regarding the starting dose of 5 mg of normal-release morphine (NRM) sulfate oral solution every 4 hours in opioid naive patients or 10 mg in patients already being treated with "weak" opioids is effective and could be proposed as starting routine dose in clinical practice. Secondary aims were to estimate the percentage of patients who were high responders to NRM and to study the association of baseline patient characteristics with both high analgesic responsivity and the need of opioid dose escalation.

Consecutive strong opioid-naive patients with cancer pain were enrolled in a multicenter uncontrolled phase 4 clinical trial. Oral NRM was administered at 2 different dosages: 5 and 10 mg every 4 hours, respectively, for opioids-naive (group A) and nonopioids-naive (group B) patients as starting therapy. Average daily dosages of NRM and opioid escalation index (OEI) were calculated and the reduction in pain score was tested through Student t test both in group A and in group B patients.

One hundred fifty-nine consecutive patients were enrolled and data analysis was conducted on 151 (95%) patients. On an average the OEIs were: 3.2 in group A and 6.5 in group B and a significant reduction in pain score both after 3 and 5 days from baseline (P<0.001) was shown in both groups. In multivariate analysis both Karnofsky Performance Status and episodic pain showed to be independent prognostic factors of a high analgesic response. The presence of neuropathic pain showed to be associated with a higher OEI.

These data show that empiric standard doses of NRM during titration, recommended by European Association for Palliative Care, are effective in clinical practice.