Abstract
BACKGROUND: Once a patent expires, generic analogue drugs are alternatives to brand name drugs. Because bioequivalence/biodistribution problems have been reported for many generic analogue drugs, we prospectively evaluated 31 patients to reveal the differences in the doses used and the efficacy and adverse events of two different intravenous esmolol formulations. METHODS: This was a prospective observational pilot study. Our aim was to reveal the possible differences in the required doses between two different formulations (brand name drug vs generic analogue drug) of intravenous esmolol in beats per minute, systolic blood pressure, diastolic blood pressure and mean arterial pressure in intra- and postoperative patients with supraventricular tachycardia and hypertension. The patients were categorised into two groups according to the medication they received (brand name drug or generic analogue drug). RESULTS: Esmolol was given to 31 patients (16 generic analogue drug and 15 brand name drug). Although there was a statistically significant difference in bolus (mg/kg) and continued (mg/kg/h) drug dose used (brand name drug/generic analogue drug, mean (standard deviation), 0.3 (0.1) vs 0.38 (0.1), p = 0.03 for bolus dose, and 0.22 (0.09) vs 0.29 (0.08) for continued dose at 10 min (p = 0.03), 0.19 (0.06) vs 0.24 (0.05) at 20 min (p = 0.01) and 0.14 (0.05) vs 0.18 (0.05) at 30 min (p = 0.02)), there were no time-related statistical significant differences in the reduction rates of the two drugs (p = 0.47). There were no time-related statistically significant differences between the two groups in systolic blood pressure, diastolic blood pressure, mean arterial pressure and beats per minute, nor in their adverse events. CONCLUSION: In this pilot study, smaller doses were given for controlling the patient's haemodynamics when a brand name drug was used. Because there were no significant time-related differences in the reduction rates of the two drugs nor in any haemodynamic differences between the two groups, optimal titration of the drug used could effectively control the patient's haemodynamics. The adverse events were also similar in both groups.