Hi thanks for asking question. ACE inhibitors and ARB are good drug for hypertension along with preventing renal damage and good for diabetic patient Also. More or less they are related to renin angiotensin system blockage and so combination of these two is not required. You can take any one of them. Along with it do life style change like less salt, low fat, green leafy vegetables, more water , avoid smoke, exercise ... If still no improvement then combination drug used with other drugs like act by different mechanism.... I hope your concern solved. Take care. Dr.parth