For control of blood pressure (BP), initially one drug is prescribed. If one drug does not control BP effectively, then a combination of two, three, and four drugs depending upon control of BP, is prescribed. You have high BP since a long time. High BP causes lots of complication such increased thickening of heart muscle (left ventricular hypertrophy) due to high pressure and kidney disorder such as loss of precious protein especially in long standing high BP . These drugs not only control high blood pressure but also prevent and cure complications of high BP. So in brief, you need a combination of drugs for effective control of BP and prevention of complications of high BP. Advice 1. Continue Zestril as suggested 2. Do not alter dose or drug unless advised by your doctor 3. Add hydrochlorothiazide 12.5 mg daily orally 4. Regular exercise at least 30 minutes for 5 days in a week. The best types of exercise for lowering BP are walking, jogging, cycling, swimming and dancing 5. Eating a diet that is rich in whole grains, fruits, vegetables and low-fat dairy products and skimps on saturated fat and cholesterol 6. Consume less salt 7. Avoid smoking, alcohol, coffee and caffeinated beverages 8. Lose extra weight if you are overweight and keep your body mass index between 19 and 25. BMI is calculated by formula BMI = Weight in Kilograms / (height in meters x height in meters) 9. Reduce your metal stress because stress activates sympathetic system and increases BP 10. Measure your BP regularly and be in touch with your doctor I hope this information will help you. I will be happy if you ask another question Thanks