Fixed irbesartan/amlodipine combination: Efficacy and safety of the use of four dosing regimens in patients with arterial hypertension

Aim: to assess efficacy, safety, and tolerability of 4 fixed irbesartan/amlodipine combinations in hypertensive patients resistant to monotherapy with 150 mg irbesartan or 5 mg amlodipine in a 16 week prospective open uncontrolled randomized multicenter study. Material and methods. We included in this study 158 patients with essential arterial hypertension (AH) (mean age 57.6 ±10.1 years, 119 women) receiving monotherapy with 150 mg irbesartan (n = 78; 49.4%) or 5 mg amlodipine (n = 80; 50.6%). Patients not achieving target arterial pressure (AP) <140/90 mm (n = 149) Hg were given fixed irbesartan/amlodipine combination 150/5 mg. If target AP was not achieved patients were randomized to 150/10 or 300/5 mg combinations. If necessary after 4 more weeks these doses were increased to maximal (300/10 mg). Thus 4 fixed irbesartan/amlodipine combinations were used: 150/5, 150/10, 300/5, 300/10 mg. Primary criterion of efficacy was portion of patients with target AP at last visit. Safety was assessed by presence of unfavorable events, clinical and laboratory parameters. Results. After 16 weeks 43, 23.5, 23.5 and 8.7% of patients received 150/5, 150/10, 300/5 and 300/10 mg combinations, respectively. At final visit 93.3% of patients had AP < 140/90 mm Hg. Mean AP lowering in the total group was -21.7±9.1/-10.9±10.8 mm Hg (p<0.0001). There were 2 cases of ankle edema (5.7%) but no withdrawals due to unfavorable events. There were no differences between 4 dosing regimens in laboratory and clinical parameters of safety and tolerability. Conclusion. In patients with AH not achieving target AP on monotherapy with irbesartan 150 or amlodipine 5 mg administration of irbesartan/ amlodipine combination with possibility of dose titration using 4 fixed combinations was effective in 93.3% of patients, resulted in significant systolic and diastolic AP lowering in all therapeutic groups, was well tolerated and safe.