| Pharmacotherapeutic group: Angiotensin II antagonists and calcium channel blockers, ATC code C09DB02.
Mechanism of action
Sevikar is a combination of an angiotensin II receptor antagonist, olmesartan medoxomil, and a calcium channel blocker, amlodipine besilate. The combination of these active ingredients has an additive antihypertensive effect, reducing blood pressure to a greater degree than either component alone.
Clinical efficacy and safety
Sevikar In an 8-week, double-blind, randomised, placebo-controlled factorial design study in 1940 patients (71% Caucasian and 29% non-Caucasian patients), treatment with each combination dose of Sevikar resulted in significantly greater reductions in diastolic and systolic blood pressures than the respective monotherapy components. The mean change in systolic/diastolic blood pressure was dose-dependent: -24/-14 mmHg (20 mg/5 mg combination), -25/-16 mmHg (40 mg/5 mg combination) and -30/-19 mmHg (40 mg/10 mg combination). Sevikar 40 mg/5 mg reduced seated systolic/diastolic blood pressure by an additional 2.5/1.7 mmHg over Sevikar 20 mg/5 mg. Similarly Sevikar 40 mg/10 mg reduced seated systolic/diastolic blood pressure by an additional 4.7/3.5 mmHg over Sevikar 40 mg/5 mg.The proportions of patients reaching blood pressure goal (< 140/90 mmHg for non-diabetic patients and < 130/80 mmHg for diabetic patients) were 42.5%, 51.0% and 49.1% for Sevikar 20 mg/5 mg, 40 mg/5 mg and 40 mg/10 mg respectively.The majority of the antihypertensive effect of Sevikar was generally achieved within the first 2 weeks of therapy.A second double-blind, randomised, placebo-controlled study evaluated the effectiveness of adding amlodipine to the treatment in Caucasian patients whose blood pressure was inadequately controlled by 8 weeks of monotherapy with 20 mg olmesartan medoxomil. In patients who continued to receive only 20 mg olmesartan medoxomil, systolic/diastolic blood pressure was reduced by -10.6/ -7.8 mmHg after a further 8 weeks. The addition of 5 mg amlodipine for 8 weeks resulted in a reduction in systolic/diastolic blood pressure of -16.2/-10.6 mmHg (p = 0.0006). The proportion of patients reaching blood pressure goal (< 140/90 mmHg for non-diabetic patients and < 130/80 mmHg for diabetic patients) was 44.5% for the 20 mg/5 mg combination compared to 28.5% for 20 mg olmesartan medoxomil.A further study evaluated the addition of various doses of olmesartan medoxomil in Caucasian patients whose blood pressure was not adequately controlled by 8 weeks of monotherapy with 5 mg amlodipine. In patients who continued to receive only 5 mg amlodipine, systolic/diastolic blood pressure was reduced by -9.9/ -5.7 mmHg after a further 8 weeks. The addition of 20 mg olmesartan medoxomil resulted in a reduction in systolic/diastolic blood pressure of -15.3/-9.3 mmHg and the addition of 40 mg olmesartan medoxomil resulted in a reduction in systolic/diastolic blood pressure of -16.7/-9.5 mmHg (p < 0.0001). The proportions of patients reaching blood pressure goal (< 140/90 mmHg for non-diabetic patients and < 130/80 mmHg for diabetic patients) was 29.9% for the group who continued to receive 5 mg amlodipine alone, 53.5% for Sevikar 20 mg/5 mg and 50.5% for Sevikar 40 mg/5 mg.Randomised data in uncontrolled hypertensive patients, comparing the use of medium dose Sevikar combination therapy versus escalation to top dose monotherapy of amlodipine or olmesartan, are not available.The three studies performed confirmed that the blood pressure lowering effect of Sevikar once daily was maintained throughout the 24-hour dose interval, with trough-to-peak ratios of 71% to 82% for systolic and diastolic response and with 24-hour effectiveness being confirmed by ambulatory blood pressure monitoring. The antihypertensive effect of Sevikar was similar irrespective of age and gender, and was similar in patients with and without diabetes. In two open-label, non-randomised extension studies, sustained efficacy using Sevikar 40 mg/5 mg was demonstrated at one year for 49 - 67% of patients. Olmesartan medoxomil (active ingredient of Sevikar)The olmesartan medoxomil component of Sevikar is a selective angiotensin II type 1 (AT1) receptor antagonist. Olmesartan medoxomil is rapidly converted to the pharmacologically active metabolite, olmesartan. Angiotensin II is the primary vasoactive hormone of the renin-angiotensin-aldosterone system and plays a significant role in the pathophysiology of hypertension. The effects of angiotensin II include vasoconstriction, stimulation of the synthesis and release of aldosterone, cardiac stimulation and renal reabsorption of sodium. Olmesartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by blocking its binding to the AT1 receptor in tissues including vascular smooth muscle and the adrenal gland. The action of olmesartan is independent of the source or route of synthesis of angiotensin II. The selective antagonism of the angiotensin II (AT1) receptors by olmesartan results in increases in plasma renin levels and angiotensin I and II concentrations, and some decrease in plasma aldosterone concentrations. In hypertension, olmesartan medoxomil causes a dose-dependent, long-lasting reduction in arterial blood pressure. There has been no evidence of first-dose hypotension, of tachyphylaxis during long-term treatment, or of rebound hypertension after abrupt cessation of therapy.Following once daily administration to patients with hypertension, olmesartan medoxomil produces an effective and smooth reduction in blood pressure over the 24 hour dose interval. Once daily dosing produced similar decreases in blood pressure as twice daily dosing at the same total daily dose.With continuous treatment, maximum reductions in blood pressure are achieved by 8 weeks after the initiation of therapy, although a substantial proportion of the blood pressure lowering effect is already observed after 2 weeks of treatment. The effect of olmesartan medoxomil on mortality and morbidity is not yet known. Amlodipine (active ingredient of Sevikar)The amlodipine component of Sevikar is a calcium channel blocker that inhibits the transmembrane influx of calcium ions through the potential-dependent L-type channels into the heart and smooth muscle. Experimental data indicate that amlodipine binds to both dihydropyridine and non-dihydropyridine binding sites. Amlodipine is relatively vessel-selective, with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. The antihypertensive effect of amlodipine derives from a direct relaxant effect on arterial smooth muscle, which leads to a lowering of peripheral resistance and hence of blood pressure. In hypertensive patients, amlodipine causes a dose-dependent, long-lasting reduction in arterial blood pressure. There has been no evidence of first-dose hypotension, of tachyphylaxis during long-term treatment, or of rebound hypertension after abrupt cessation of therapy. Following administration of therapeutic doses to patients with hypertension, amlodipine produces an effective reduction in blood pressure in the supine, sitting and standing positions. Chronic use of amlodipine is not associated with significant changes in heart rate or plasma catecholamine levels. In hypertensive patients with normal renal function, therapeutic doses of amlodipine reduce renal vascular resistance and increase glomerular filtration rate and effective renal plasma flow, without changing filtration fraction or proteinuria. In haemodynamic studies in patients with heart failure and in clinical studies based on exercise tests in patients with NYHA class II-IV heart failure, amlodipine was found not to cause any clinical deterioration, as measured by exercise tolerance, left ventricular ejection fraction and clinical signs and symptoms.A placebo-controlled study (PRAISE) designed to evaluate patients with NYHA class III-IV heart failure receiving digoxin, diuretics and ACE inhibitors has shown that amlodipine did not lead to an increase in risk of mortality or combined mortality and morbidity in patients with heart failure.In a follow-up, long-term, placebo controlled study (PRAISE-2) of amlodipine in patients with NYHA III and IV heart failure without clinical symptoms or objective findings suggestive of underlying ischaemic disease, on stable doses of ACE inhibitors, digitalis, and diuretics, amlodipine had no effect on total or cardiovascular mortality. In this same population amlodipine was associated with increased reports of pulmonary oedema despite no significant difference in the incidence of worsening heart failure as compared to placebo. | |