Comparison of analgesic effect of morphine alone and combination of morphine with dextromethmorphan

Objective:To standardize the method for morphine dose titration and investigate the synergistic effect of dextromethorphan with morphine on cancer pain.Methods:Eighty six adult patients with severe cancer pain were selected.The experiment was divided into two stages:the stage of morphine dose titration and random double-blind contrast test.At the stage of morphine dose titration the patients were administered morphine 5 mg/4 h at baseline and given as needed morphine palliative treatment at 10% total daily dosage when abrupt pain occurred till the patients gained stable pain.At the stage of random double-blind contrast test the dosage of morphine was reduced by 30% and dextromethorphan or its analogue tablets(dose ratio 1∶1) was added.Morphine dose titration was performed again till pain relief.Results:During the stage of morphine dose titration the dose of morphine was increased from the second day.The dose of morphine was stabilized on the fourth day.Morphine was given to the patients at the stable dose continuously.The minimum pain-relieving dose of morphine was 30 mg and the maximum dose was 160 mg.The pain intensity of the patients began weaker from the third day and kept stable during the treatment.The life qualities of the patients were obviously improved.During contrast test stage the total dose of morphine was reduced in both groups.The dose of morphine was reduced a little more after addition of dextromethorphan compared with the control group.But there was no significant difference between the two groups.The pain intensity kept stabilized during the treatment.Conclusion:Standardized morphine dose titration achieved satisfactory effects on cancer pain.Addition of dextromethorphan tended to reduce the total dose of morphine.