14 General information
Consequently, dosages of antihyperten-
sive drugs must be carefully individualised.
In older adults, overly aggressive treatment
of high blood pressure may do more harm
thangood, so treatment goals shouldbe rea-
sonable. Although bringing blood pressure
down to 120/85 mmHg may be appropri-
ate in a young hypertensive person, a more
reasonable goal for an older hypertensive
person might be 150/95 mmHg.
Digoxin toxicity
As the body’s renal function and excretion
rate decline, digoxin concentrations in the
blood may build to toxic levels, causing
nausea, vomiting, diarrhoea and—most
seriously—cardiac arrhythmias. Try to pre-
vent severe toxicity by monitoring serum
drug levels and by observing the person for
early signs or symptoms, such as appetite
loss or visual disturbances.
Corticosteroid toxicity
Older adults on corticosteroids may expe-
rience short-term effects, including fluid
retention and psychological manifestations
ranging from mild euphoria to acute psy-
chotic reactions. Long-term toxic effects,
such as osteoporosis, can be especially
severe in older adults who have been taking
prednisone or related steroidal compounds
for months or even years. To prevent seri-
ous toxicity, carefully monitor individuals
on long-term regimens. Observe them for
subtle changes in appearance, mood and
mobility; signs of impaired healing; and fluid
and electrolyte disturbances.
Anticoagulant effects
Older adults taking anticoagulants have an
increased risk of bleeding, especially when
they take NSAIDs concomitantly (as many
do). Observe the INR carefully, and monitor
the person for bruising and other signs of
bleeding.
Sleeping-aid toxicity
Sedatives or sleeping aids, such as nitraz-
epam, may cause excessive sedation or
Be sure to observe the individual for signs
or symptoms of toxicity. A person receiv-
ing digoxin, for example, may experience
anorexia, nausea, vomiting or confusion.
Adverse drug reactions
Compared with younger people, older
adults experience twice as many adverse
drug reactions because of multiple-drug
therapy, poor compliance and physiologi-
cal changes. Signs and symptoms of adverse
drug reactions—confusion, weakness and
lethargy—are commonlymistaken for senil-
ity or indications of disease. If the adverse
reaction is not identified, the person may
continue to receive the drug. Furthermore,
the person may receive unnecessary addi-
tional medication to treat complications
caused by the original medication. This
may lead to a pattern of inappropriate and
excessive medication use.
Although any medication can cause
adverse reactions, themost serious reactions
in the older adult are causedby relatively few
medications.Beparticularlyalertfortoxicities
resulting from diuretics, antihypertensives,
digoxin, corticosteroids, anticoagulants,
sleeping aids and nonprescription drugs.
Diuretic toxicity
Because total body water content decreases
with age, normal dosages of potassium-
wasting diuretics, such as hydrochlorothia-
zide and frusemide, may result in fluid loss
and even dehydration in an older person.
These diuretics may deplete serum potas-
sium, causing weakness, and may elevate
blood uric acid and glucose levels, com-
plicating pre-existing gout and diabetes
mellitus.
Antihypertensive toxicity
Many older adults experience light-
headedness or fainting when using antihy-
pertensive medications, partly in response
to atherosclerosis and decreased elasticity
of blood vessels. Antihypertensive drugs
may reduce blood pressure too rapidly,
resulting in dizziness or fainting.
