Effect of fixed dose combinations of metoprolol and amlodipine in essential hypertension: MARS - A randomized controlled trial

Aim. To compare two strengths of a fixed drug combination (FDC) containing metoprolol XL and amlodipine (metoprolol/amlodipine 50/5; and metoprolol/amlodipine 25/2.5) with its components in hypertension. Methods. We conducted this multicentre, randomized, open-label, trial in Indian patients with hypertension (140-180 mmHg/90-114 mmHg) in 11 centres from nine cities. Eligible patients (n = 402) were randomized into one of five treatment groups (metoprolol XL 50 mg + amlodipine 5 mg, metoprolol XL 25 mg + amlodipine 2.5 mg, metoprolol XL 50 mg, metoprolol XL 25 mg or amlodipine 5 mg) and treated for 8 weeks with five follow-up visits to record blood pressure (BP) and clinical status. Results. At baseline, treatment groups were well balanced; mean +/- SD BP was 154.87 +/- 11.91/96.63 +/- 6.97 mmHg. The greatest reduction in BP from baseline to 8 weeks was seen in the high-dose FDC group (23.61/14.91 mmHg; p < 0.001). The remaining 4 groups too demonstrated a significant reduction (p < 0.001): low-dose FDC -2.29/-14.66; metoprolol 50, -23.17/-13.37; metoprolol 25, -18.41/-12.50 and amlodipine 5, -23.01/-13.08. BP reductions by FDCs, however, were not statistically superior to monotherapies. Responder rates (sitting diastolic BP < 90 mmHg or reduction >= 10 mmHg) were 93% in the high-dose FDC group and 97% in the low-dose FDC group, and control rates (sitting BP < 140/90 mmHg) were 66% and 58%, respectively. These rates were higher than that seen in individual components. There were no reports of serious adverse events related to study medications. One each from the low-dose FDC and metoprolol 25 mg group discontinued because of adverse events. Conclusions. FDCs of metoprolol and amlodipine are effective and safe in mild to moderate hypertension.