baseline for safe use of a drug. RESULTS: SVR and PVR failed to show statistically significant changes. Heart rates were increased only at 2 minute after administration of chlorpheniramine maleate. Blood pressures were increased but returned to basal level within 4 minutes. Cardiac output showed statistically significant increase until 8 minutes. However, the changes of hemodynamic values were maintained within 20% of basal levels. CONCLUSIONS: Chlorpheniramine maleate is observed to cause statistically significant hemodynamic change after intravenous administration during anesthesia. But the changes were within 20% of basal levels, and we can safely use chlorpheniramine maleate 8 mg IV in the view of hemodynamic changes.