Study of clinical effect of original and generic amlodipines in arterial hypertension with obesity: results of randomized cross-over study

Aim. To study the influence of amlodipine compounds: original and generic — on the levels of blood pressure (BP), under conditions of isometric load as well; on metabolic parameters and some factors of atherothrombogenesis, in patients with arterial hypertension (AH) and obesity.

Material and methods. Totally, 30 patients included, with AH 1-2 grade, and obesity. After 2 weeks washout they were randomized to the group of original amlodipine and generic amlodipine (GA). Beginning dose was 5 mg and in 2 weeks increased to 10 mg daily if target BP was not reached  (<140/90 mmHg). After finishing treatment period by the first drug, there was 2-week washout and then the same therapy period but with another drug. Total duration of each compound was 6 weeks. Clinical examination was performed, as 24-hour monitoring of BP (ABPM), arm isometric test, lipids and lipoproteids concentration, glucose and insulin levels, platelet aggregation assessed spontaneous and under adenosine diphosphate (ADP) and adrenalin activation in various concentrations. Life questionnaires were used, hospital score for anxiety and depression.

Results. In 6 weeks there was decrease of systolic (SBP) and diastolic (DBP) BP levels sitting, with Norvasc® by 21,7±8,2 mmHg (р<0,001) and by 12,3±4,6 mm Hg (р<0,001), in GA by 18,8±5,8 mmHg (р<0,001) and 11,3±5,6 mmHg (р<0,001). At the background of both amlodipines, there was comparable with BP decrease change of ABPM rates. This was related to decrease of heart rate (HR) while sitting by 4,2±6,4 bpm (р=0,002) in Norvasc® and by 3,3±4,4 bpm (р=0,004) in GA. After 6 weeks of Norvasc® and GA there was decline of the mean SBP/DBP levels at the peak of isometric load: by 20,2±11,6/10,2±5,2 mmHg (р<0,001) and by 14,7±9,7/9,2±11,6 mmHg (р<0,001), respectively. Also, the mean peak SBP decreased more significantly on Norvasc®. As a respond to isometric load after Norvasc® intake, there was decline of DBP increase, and after GA, contrary, increase of SBP and DBP raise. This was related to the increase of the double rate by 30,2% (p<0,05) on Norvasc® and absence of such dynamics on GA. Therapy by the both led to decrease of total cholesterol and low density cholesterol. There was positive trend on platelet ADP- aggregation decline in Norvasc®, and increase in GA. There were less side effects in Norvasc®.

Conclusion. In AH patients with obesity the generic amlodipine showed comparable results in dynamics of BP and HR, measured in sitting and standing position, and by ABPM data. However, original amlodipine had higher efficacy with conditions for more economic heart working circumstances, by generic amlodipine did not reduce the hypertensive reaction in isometric muscular tension and increased aggregation potential of platelets.

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