Effervescent morphine results in faster relief of breakthrough pain in patients compared to immediate release morphine sulfate tablet.

Morphine tablets have been formulated to produce an easily ingested effervescent solution when placed in water. It was hypothesized that an aqueous solution would result in fast gastrointestinal transit with a more rapid onset of action compared to immediate release morphine sulfate (IRMS), which would be especially beneficial in treating breakthrough pain (BTP). In an open-label safety and efficacy study, effervescent morphine was given to 76 chronic cancer pain patients for treatment of BTP evaluating time until pain relief, global satisfaction and side effects. Results were compared to those obtained using an IRMS formulation in a preceding run-in period. For BTP, a mean dose of 28 mg of effervescent morphine (range 10-80 mg) resulted in a highly significant reduction of pain score (mean 7.8 to mean 3.2; P < 0.001). Efficacy was not different from that observed with IRMS. However, mean time until sufficient pain relief was significantly shorter than with IRMS (13 +/- 5.6 vs. 27 +/- 4.4 minutes; P < 0.01). The incidence of side effects was similar with the new morphine formulation and with IRMS. There was no relationship between the previous dose of the daily opioid and the effective dose of effervescent morphine. The dose for treatment of BTP was determined by individual titration and not predicted by the dose taken with the basic pain medication. Compared to IRMS, overall satisfaction for effervescent morphine was rated "superior" by 16.7%, and "better" by 63.2% of patients. Effervescent morphine offers an alternative for management of breakthrough cancer pain compared with the commonly used IRMS.