This is a multi-centre, randomised, double-blind, active-controlled, parallel-group comparative trial to compare the fixed dose combination (FDC) of telmisartan 80 mg + hydrochlorothiazide 12.5 mg and amlodipine 5 mg (T80/A5/H12.5 mg) to telmisartan 80 mg+ hydrochlorothiazide 12.5 mg (T80/H12.5 mg) in blood pressure lowering effect at week 8, the end of the double-blind period in essential hypertensive patients who fail to respond adequately to telmisartan 80 mg+ hydrochlorothiazide 12.5 mg.