Pharmacodynamic and pharmacokinetic evaluation in man of the new sympathomimetic amezinium.

Blood pressure, ECG and plasma concentration were determined for up to 12 h following single i.v. (10 mg) and oral (20 mg) doses of amezinium (Regulton) in 8 healthy, male volunteers. The i.v. and oral doses were almost equi-active in significantly increasing systolic blood pressure (SBP) by 14.5 and 15.6 mmHg, respectively. The maximum SBP after the i.v. dose was reached after 45 min, and 105 min after oral administration. The heart rate fell reflexly. The increases in mean and diastolic blood pressures were not significant. Pulse pressure was enhanced after both i.v. and oral administration. The effect on systolic blood pressure lasted for about 4 h. There was a slight shortening of the QTc duration, which could not be explained as a drug effect. Other ECG time intervals were not altered. Multiple regression analysis showed a significant positive correlation between the log plasma concentration and the increase in SBP between 0.5 and 5 h after oral administration (r = 0.78, p less than 0.001) and between 0.75 and 5 h after i.v. administration (r = 0.83, p less than 0.001). 30 min after amezinium p.o. the mean SBP began to rise, when a plasma level of about 30 ng/ml was reached.