Download Hypertension - Webstercare

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