BACKGROUND: Dialysis-induced hypotension is a very common but difficult complication to manage. Amezinium methylsulfate is a newly developed sympatho-mimetic agent which has been reported as effective in postural hypotension. We studied the preventive effect of amezinium methylsulfate on dialysis-induced hypotension in chronic hemodialysis patients. METHODS: Twenty-five hemodialysis(HD) patients who were maintaining on hemodialysis longer than 3 months and had frequent episodes of dialysis hypotension were enrolled in this study. After 4 weeks of observation period, patients received one tablet of ameziniurn 30 minutes prior to every hemodialysis session for 4 weeks. We com mean arterial pressure(MAP), number of hypotensive episodes and number of nursing interventions(defined as position change, bolus injection of saline or 50% dextrose in water, need to decrease transmembrane pressure or discon- tinuation of dialysis) between observation and medication period in each patient. RESULTS: The number of nursing interventions (mean, 2.5+/-0.9 interventions vs. 1.4+/-0.9 interventions, p<0.05) and hypotensive episodes(mean, 1.7+/-0.7 episodes per session vs. 0.9+/-0.7 episodes per session; p<0.05) decreased significantly in the medication period and the nadir MAP(57+/-13mmHg vs 70+/-15mmHg; p<0.05), mid-HD MAP(65+/-15mmHg vs. 79+/-15mmHg; p<0.05) and post-HD MAP(66+/-14mmHg vs 78+/-16 mmHg ; p<0.05) are higher in the medication period compared with observation period. CONCLUSION: These results show that amezinium methylsulfate is useful to prevent dialysis-induced hypotension in chronic hemodialysis patients.