['This study evaluated the effects on blood pressure (BP) of valsartan 160 mg or losartan 100 mg addition to amlodipine 5 mg in hypertensive patients.', '221 patients with inadequately controlled BP (DBP >or= 90 mmHg) after 4 weeks of treatment with amlodipine 5 mg were randomized to receive losartan/amlodipine combination therapy or valsartan/amlodipine combination therapy for 4 weeks in a cross-over study design. At the end of the wash-out period and of each treatment period, clinic and ambulatory BP measurements were recorded.', '166 patients completed the study. Both combination treatments induced a greater ambulatory BP reduction than did monotherapy. However, the further mean reductions in BP versus monotherapy were significantly greater with the valsartan/amlodipine combination (SBP/DBP: -7.9 +/- 3.4/-6.5 +/- 2.6 mmHg for 24-hour, -8.0 +/- 3.4/-6.6 +/- 2.7 mmHg for daytime; -7.7 +/- 3.3/-6.4 +/- 2.7 mmHg for nighttime) than with the losartan/amlodipine combination (SBP/DBP: -5.5 +/- 2.8/-4.2 +/- 2.1 mmHg for 24-hour, -5.7 +/- 2.9/-4.4 +/- 2.2 mmHg for daytime; -4.8 +/- 2.8/-3.7 +/- 2.2 mmHg for nighttime; P < 0.01 vs valsartan/amlodipine). The incidence of adverse events with valsartan/amlodipine (8%) and losartan/amlodipine (9%) was lower than that observed with amlodipine monotherapy (17%; P < 0.05 vs combinations).'] Is valsartan addition to amlodipine more effective than losartan addition in hypertensive patients inadequately controlled by amlodipine?