Objective   To investigate the analgesic effect of 10-mg morphine sulphate suppository in the treatment of patients with severe chronic cancer pain and its adverse reactions.    Methods   A randomized

double-blind

double-dummy

crossover

multicenter study was performed on 64 patients with moderate to severe cancer pain from 7 hospitals during March 2005 to March 2006. Those pathologically identified cancer patients were 18 to 75 years old

with the Karnofsky performance status scale (KPS) ≥60 and their life expectancy ≥2 months. They all were informed with the aim of this study and an informed content was signed. They were divided into group A (n=33) and group B (n=31). The patients in A group were first administered 10 mg morphine sulfate suppository by rectum and placebo by mouth

and for the second time

they were administered morphine sulfate tablet by mouth and simulation or placebo by rectum. The patients of group B used the opposite order of administration as those of group A. The analgesic efficacy and adverse reactions of 2 groups of patients were assessed.    Results   Two groups of patients had a good balance. Baseline pain score in groups A and B was 6.12±0.89 and 6.16±0.90

respectively

and the pain rating scale was 2.27±0.45 and 2.35±0.49

respectively. The difference was not statistically significant (P0.05). Onset time of pain of 2 groups in first phase was (42.93±27.30) and (40.21±24.42) min respectively. In second phase

the onset time of pain was (40.80±23.63) and  (51.04±46.44) min. The difference of onset time of pain in 2 groups was not statistically significant (P0.05). Best time to ease the pain of 2 groups in first phase was (110.07±72.92) and (104.89±73.40) min respectively. In second phase

the time was (112.33±82.08)   and (129.86±102.67) min respectively. The difference of best time to ease the pain in 2 groups was not statistically significant  (P0.05). The difference in relief and efficiency between the 2 groups were also not statistically significant(P0.05). A total of 5 patients with adverse events occurred eight times.  The main adverse reactions were dizziness

nausea

vomiting

sleepiness

etc.    Conclusion   Rectal administration of 10 mg morphine sulfate suppository for patients with severe cancer pain has good analgesic effect

and sound security.