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Continuing Education C O N S U LTA N T P H A R M A C I S T C O N T I N U I N G E D U C AT I O N S E R I E S AUGUST 2009 HYPERTENSION H ypertension (high blood pressure) is a common condition, especially in the older person. It is a major risk factor for coronary heart disease, stroke, heart failure and kidney failure. Hypertension has also been linked to dementia. Nearly 8 % of the burden of disease in Australia can be attributed to high blood pressure (BP). In 2005, hypertension was the cause of death in 9.1 % of females and 13.3 % of males. The proportion of people with hypertension increases markedly with age. At least 80 % of people aged over 65 years will have high blood pressure. Indigenous Australians are twice as likely to have hypertension. Definition Blood pressure represents the forces exerted by blood on the wall of the arteries and is written as systolic/diastolic (for example 120/80 mmHg, stated as ‘120 over 80’). Systolic blood pressure (SBP) reflects the maximum pressure in the arteries when the heart muscle contracts to pump blood. Diastolic blood pressure (DBP) reflects the minimum pressure in the arteries when the heart muscle relaxes before its next contraction. Hypertension in older people has been defined as SBP greater than or equal to 140 mmHg or SBP ≥ 160 mmHg and/or a DBP ≥ 90 mmHg. Causes Major causes of high blood pressure include diet (particularly a high salt intake), obesity, excessive alcohol consumption, and insufficient physical activity. Maintaining ideal body weight, adequate physical activity and good nutrition play an important role in maintaining healthy blood pressure. Some drugs such as NSAIDs, corticosteroids (prednisone, prednisolone), venlafaxine (Efexor) and sibutramine (Reductil) can increase blood pressure. Pseudoephedrine, used in many cough and cold preparations, only increases systolic blood pressure by about 1 mmHg, with no effect on diastolic BP. Hypertension is more common in people with diabetes. Lowering BP in people with diabetes has been shown to decrease complications. © Manrex Pty Ltd (ABN: 63 074 388 088) t/as Webstercare - 2009 Age-related changes As a person ages, the body’s physiology changes. This increases the risk of having hypertension and also influences the choice of medications used to treat the condition. Systolic and diastolic blood pressure tends to rise until about 55 years of age, after which systolic blood pressure continues to rise and diastolic usually shows little or no change. Diastolic blood pressure may even decline after 60 years of age. Isolated systolic hypertension (ISH) affects about two-thirds of people over the age of 60 years. Changes in elastin and collagen with age contribute to an increase in SBP. In some people BP decreases with ageing. This is mostly due to Alzheimer’s disease, cancer or after a heart attack. The elderly are more likely to experience side effects and drug interactions between medications and other conditions. Treatment Drug treatment of hypertension in the older person may be different to that of a younger person. Regardless of age, lifestyle modifications are necessary in all people. Losing weight and decreasing sodium intake can be very beneficial in the elderly. A low sodium diet can lower blood pressure by as much as 10 mmHg. Reducing body weight may decrease blood pressure by 5 to 15 mmHg. Listening to music for 30 minutes a day while performing controlled slow breathing exercises can significantly reduce blood pressure. Medications There are several classes of medications available for the treatment of hypertension in the elderly: ■ ■ ■ ■ ■ ■ Diuretics Alpha-blockers Beta-blockers Calcium channel blockers (CCBs) ACE inhibitors Angiotensin receptor blockers It is common that residents will benefit from a combination of agents and require 2 or more medications. Medicationscontinued shouldover be continued over Hypertension, continued started at low doses and the dose increased slowly, watching for side effects. The HYVET Study showed that treatment of hypertension in the very elderly (over 80 years of age) is beneficial and reduces the risk of stroke, heart failure and death. This study proved that it is not too late to start antihypertensive therapy in older people. The choice of blood pressure medicines will also depend on other conditions. For example, people with coexisting heart failure will benefit from ACE inhibitors, beta-blockers (carvedilol, metoprolol CR or bisoprolol) and thiazide diuretics. Residents with angina will probably require beta-blockers, CCBs or ACE inhibitors. Post-MI patients need beta-blockers or ACE inhibitors or sartans. ACE inhibitors are considered necessary in patients with diabetes. CCBs include amlodipine (Norvasc), felodipine (Felodur, Plendil), lercanidipine (Zanidip), nifedipine (Adalat), diltiazem (Cardizem) and verapamil (Isoptin, Anpec, Cordilox). ACE inhibitors ACE inhibitors reduce vasoconstriction and sodium retention. ACE inhibitors include captopril (Capoten), enalapril (Renitec), fosinopril (Monopril), lisinopril (Prinivil), perindopril (Coversyl), quinapril (Accupril), ramipril (Tritace, Ramace) and trandolapril (Gopten, Odrik). Angiotensin receptor blockers Angiotensin receptor blockers are also called sartans or angiotensin II antagonists. They also reduce vasoconstriction and sodium retention, but by a different mechanism to ACE inhibitors. Similarly, patients with asthma and hypertension should avoid beta-blockers. Verapamil and diltiazem should be avoided in patients with heart failure. Thiazide diuretics can increase the risk of gout. Angiotensin receptor blockers include candesartan (Atacand), Eprosartan (Teveten), irbesartan (Avapro, Karvea), losartan (Cozaar), olmesartan (Olmetec), telmisartan (Micardis) and valsartan (Diovan). Diuretics Side effects Diuretics are generally considered as first-line therapy for the treatment of high blood pressure. Diuretics promote fluid loss by altering how the kidneys handle sodium. Diuretics include thiazides such as hydrochlorothiazide (Dithiazide), chlorthalidone (Hygroton), indapamide (Natrilix), frusemide (Lasix), ethacrynic acid (Edecrin), potassium-sparing agents such as spironolactone (Aldactone), eplerenone (Inspra), amiloride (Midamor). Many combination products are available with diuretics. The side effects of blood pressure drugs include an increased risk of falls due to hypotension (low blood pressure), dizziness and syncope. All drugs used for control of hypertension are likely to contribute to varying degrees in these effects. Multiple medications may allow lower doses of each drug and minimise these adverse effects. Lower body weight and frailty increase the risk of these side effects. Sartans are generally used in people who cannot tolerate the persistent dry cough commonly caused by ACE inhibitors. Conclusions Beta-blockers Beta-blockers include oxprenolol (Corbeton), pindolol (Visken), propranolol (Inderal), atenolol (Noten, Tenormin), bisoprolol (Bicor), and metoprolol (Toprol XL, Minax, Lopresor, Betaloc). Some studies suggest that beta-blockers are first-line hypertension therapy in the elderly. They are also used for other conditions such as heart failure, previous myocardial infarction (heart attack) or coronary disease. Alpha-blockers Alpha-blockers usually are not used as first-line therapy in the elderly and should only be used in conjunction with other antihypertensives. It is important to always consider the saying “start low and go slow” when prescribing medications in the older person. It is preferable to use a once-daily dose of medications. Coexisting diseases need to be considered when choosing the most appropriate treatments. Lifestyle changes including weight reduction and low salt diets are necessary in all persons with high blood pressure. References Australia’s Health 2008. N Engl J Med 2008;358:1887-1898. The Webstercare Consultant Pharmacist Continuing Education Service come to you each month from your pharmacist. If you would like extra copies please visit www.webstercare.com.au or ask your pharmacist. Carvedilol (Dilatrend, Kredex) and labetalol (Trandate, Presolol) are alpha- and beta-blockers. Calcium channel blockers Calcium channel blockers (CCBs) produce smooth muscle relaxation, decrease vascular resistance and thereby lower blood pressure. © Manrex Pty Ltd (ABN: 63 074 388 088) t/as Webstercare - 2009 17-19 MOORE STREET, LEICHHARDT NSW 2040 PHONE: (02) 9563 4900 • FREECALL: 1800 244 358 • FAX: (02) 9563 4955 FREE FAX: 1800 MANREX (1800 626 739) • WWW.WEBSTERCARE.COM.AU