C H A P T E R 4 3
Drugs affecting blood pressure
667
BOX 43.4
Drug therapy across the lifespan (continued)
evaluated.The importance of other measures to help
lower blood pressure—weight loss, smoking cessation,
increased activity—should be stressed.
PREGNANCY AND BREASTFEEDING
The safety for the use of these drugs during pregnancy
has not been established. ACE inhibitors, ARBs and renin
inhibitors should not be used during pregnancy. Women
of childbearing age should be advised to use barrier
contraceptives to prevent pregnancy while taking these
drugs. Calcium channel blockers and vasodilators should
not be used in pregnancy unless the benefit to the mother
clearly outweighs the potential risk to the fetus.The drugs
do enter breast milk and can cause serious adverse effects
in the baby. Caution should be used or another method of
feeding the baby should be used if one of these drugs is
needed during breastfeeding.
OLDER ADULTS
Older adults frequently are prescribed one of these drugs.
They are more susceptible to the toxic effects of the
drugs and are more likely to have underlying conditions
that could interfere with drug metabolism and excretion.
Renal or hepatic impairment can lead to accumulation
of the drugs in the body. If renal or hepatic dysfunction
is present, the dose should be reduced and the person
monitored very closely.
The total drug regimen of the older person should be
coordinated, with careful attention to interactions among
drugs and alternative therapies.
Older adults need to use special caution in any situation
that could lead to a fall in blood pressure, such as loss
of fluids from diarrhoea or vomiting, lack of fluid intake,
or excessive heat with decreased sweating that comes
with age. Dizziness, falls or syncope can occur if the
blood pressure falls too far in these situations.The blood
pressure should always be taken immediately before an
antihypertensive is administered to an older adult in an
institutional setting to avoid excessive lowering of blood
pressure.
Older people should be especially cautioned about
sustained-release antihypertensives that cannot be cut,
crushed or chewed to avoid the potential for excessive
dosing if these drugs are inappropriately cut.
FIRST CHOICE
ACE inhibitor (or angiotensin II receptor antagonist) or calcium
channel blocker, or low-dose thiazide diuretic (consider for people
aged ≥ 65 years only)
IF TARGET BP NOT REACHED
ACE inhibitor (or
angiotensin II receptor
antagonist) + calcium
channel blocker
ACE inhibitor (or
angiotensin II receptor
antagonist) + calcium
channel blocker +
low-dose thiazide
diuretic
ACE inhibitor (or
angiotensin II receptor
antagonist) + low-dose
thiazide diuretic
Consider seeking
specialist advice
or
IF TARGET BP NOT REACHED
IF TARGET BP NOT REACHED
FIGURE 43.4
Algorithm for the treatment of hypertension.
Source:
Heart Foundation (2010). In Guide to Management of Hypertension:
Assessing and Managing Raised Blood Pressure in Adults, p. vi. Available at:
HypertensionGuidelines2008to2010Update.pdf.
