666
P A R T 8
Drugs acting on the cardiovascular system
TABLE 43.2
DRUGS IN FOCUS Antihypertensive agents (continued)
Drug name
Dosage/route
Usual indications
Calcium channel blockers (continued)
lercanidipine (Lercan,
Zanidip, Zircol)
10–20 mg/day PO
Used alone or in combination with other
agents for treatment of hypertension in
adults
nifedipine (Adalat, Adefin,
Nyefax)
30–60 mg/day PO
Extended-release preparations only for the
treatment of hypertension in adults; other
preparations are used for angina
verapamil (Anpec,
Cordilox SR, Isoptin)
120–240 mg/day PO, reduce dose in the
morning; extended release capsules:
100–300 mg/day PO at bedtime
Extended-release formulations for the
treatment of essential hypertension;
other preparations are used for angina
and treating various arrhythmias in adults
Vasodilators
diazoxide (generic)
1–3 mg/kg IV, by rapid bolus over 30 seconds;
may be repeated q 5–15 minutes as needed
Treatment of severe hypertension in
hospitalised adults
hydralazine (Alphapress,
Apresoline)
5–10 mg by slow IV, or continuous infusion
200–300 mcg/minutes
Paediatric: 1.7–3.5 mg/kg per 24 hours IV or IM
in four to six divided doses
Treatment of severe hypertension
minoxidil (Loniten)
Adult: 10–40 mg/day PO in divided doses
Paediatric (<12 years): 0.25–1 mg/kg per day
PO as a single dose
Treatment of severe hypertension
unresponsive to other therapy
sodium nitroprusside
(generic)
Adult and paediatric: 3 mcg/kg per minute,
do not exceed 10 mcg/kg per minute
Treatment of hypertensive crisis; also used
to maintain controlled hypotension during
surgery
Other antihypertensive agents
Diuretic agents
See Chapter 51
See Chapter 51
Treatment of mild hypertension; often first
agents used; often used in combination
with other agents
Sympathetic nervous system blockers
See Chapter 31
See Chapter 31
BOX 43.4
Drug therapy across the lifespan
Drugs affecting blood pressure
CHILDREN
National standards for determining normal levels of blood
pressure in children are quite new. It has been determined
that hypertension may start as a childhood disease, and
more screening studies are being done to establish normal
values for each age group.
Children are thought to be more likely to have
secondary hypertension, caused by renal disease or
congenital problems such as coarctation of the aorta.
Treatment of childhood hypertension should be done
very cautiously because the long-term effects of the
antihypertensive agents are not known. Lifestyle changes
should be instituted before drug therapy if at all possible.
Weight loss and increased activity may bring an elevated
blood pressure back to normal in many children.
If drug therapy is used, a mild diuretic may be tried
first, with monitoring of blood glucose and electrolyte
levels on a regular basis. Beta-blockers have been used
with success in some children; adverse effects may limit
their usefulness in others.The safety and efficacy of the
angiotensin-converting-enzyme (ACE) inhibitors and
the angiotensin-receptor blockers (ARBs) have not been
established in children. Calcium channel blockers have
been used to treat hypertension in children and may be
a first consideration if drug therapy is needed. Careful
follow-up of the growing child is essential to monitor for
changes in blood pressure, as well as for adverse effects.
ADULTS
Adults receiving any of these drugs need to be
instructed about adverse reactions that should be
reported immediately.They need to be reminded of
safety precautions that may be needed in hot weather
or with conditions that cause fluid depletion (e.g.
diarrhoea, vomiting). If they are taking any other drugs,
the interacting effects of the various drugs should be
