CARDIOVASCULAR JOURNAL OF AFRICA • Vol 21, No 2, March/April 2010
124
AFRICA
Opinions in Hypertension Management
Angiotensin receptor blockers (ARBs) in hypertension patients: earlier use of these better-
tolerated medications is warranted
All patients with hypertension are at
increased risk for vascular events and
hypertension is widely regarded as one of
the most important risk factors for cardio-
vascular disease.
1
At all ages, there is a
positive and graded relationship between
usual blood pressure and the risk of cardio-
vascular and stroke mortality.
2
The role of the renin–angiotensin–
aldosterone system (RAAS), even in the
early stages of the cardiovascular contin-
uum, is well-established, with positive
results being obtained in clinical trials
of cardiovascular event reduction using
specific RAAS blockers.
In hypertension management, toler-
ability is key to patient compliance and
the long-term reduction of cardiovascular
events. ARBs with placebo-like tolerabil-
ity and efficacy in reducing cardiovascu-
lar and cerebrovascular events should be
favoured in guidelines.
3
ARBs reduce blood pressure at least to
the same extent asACE inhibitors andmore
so in some cases. For example, the largest
study undertaken to compare an ARB
with an ACE inhibitor, the 1 600-patient
Prospective Randomized Investigation of
the Safety and efficacy of Micardis versus
ramipril using Ambulatory blood pres-
sure monitoring (PRISMA) study found
greater blood pressure reductions from
telmisartan than ramipril.
4
There is significant evidence of
within-class differences among ARBs
with respect to their plasma half-lives,
lipophilicity and receptor-binding affin-
ity. Drugs in the ARB class also differ in
their antihypertensive efficacy.
5
Clinicians
should evaluate these aspects careful-
ly when selecting ARBs for individual
patients.
There is also increasing evidence that,
as with ACE inhibitors, ARBs confer
benefits beyond their blood pressure-
lowering effects by reducing morbidity
and mortality in cardiovascular, renal and
cerebrovascular outcomes through renin–
angiotensin system (RAS) blockade.
6
Hypertensive patients at
increased risk
Telmisartan is the only ARB that has
demonstrated therapeutic equivalence to
the ACE inhibitor ramipril in hyperten-
sive patients at increased vascular risk.
The patient population in this study
(ONTARGET) is of particular interest
as it is representative of the majority of
hypertensive patients seen in everyday
clinical practice.
The findings from this study showed
that telmisartan 80 mg per day was as
efficacious as the proven dosage of
ramipril (10 mg/day) in reducing risk of
cardiovascular death, myocardial infarc-
tion, stroke and hospitalisation for heart
failure in a broad cross section of high-
risk cardiovascular patients. It achieved
these results with far fewer side effects,
resulting in significantly fewer patients
discontinuing therapy.
7
Implications for practice
In clinical practice, ARBs are linked to
greater patient adherence and to better
blood pressure control. For this reason,
first-line ARBs can offer improved effi-
cacy, greater compliance and reduced
healthcare utilisation, which offset higher
acquisition costs.
Importantly, allACE-intolerant patients
who are at risk of diabetes, myocardiaI
infarction, stroke or peripheral arterial
disease should be switched to the ARB
with proven benefit.
J Aalbers, Special Assignments Editor
Verdecchia Paolo,
1.
et al
. Comparative assess-
ment of angiotensin receptor blockers in
different settings.
Vasc Hlth Risk Mngmt
2009;
5
: 939–948.
Leurington,
2.
et al
. Age-specific relevance of
usual blood pressure to vascular mortality:
a meta-analysis of individual data for one
million adults in 61 prospective studies.
Lancet
2002;
360
(9349): 1903–1913.
Neldam S. Choosing an angiotensin-receptor
3.
blocker: blood pressure lowering, cardio-
vascular protection or both?
Future Cardiol
2010;
6
(1): 129–135.
Williams B, Lacourciere Y, Schumacher H,
4.
Gosse P, Neutel JM. Antihypertensive effi-
cacy of telmisartan vs ramipril over the 24-h
dosing period, including the critical early
morning hours: a pooled analysis of the
PRISMA I and II randomized trials.
J Hum
Hpertens
2009;
23
(9): 610–619.
Lacourciere Y, Krezesinski JM, White WB,
5.
Davidai G, Schumacher H. Sustained antihy-
pertensive activity of telmisartan compared
with Valsartan.
Blood Pres Monit
2004;
9
:
203–210.
Carson P,Giles T, Higgenbotham M,
6.
et al
.
Angiotensin receptor blockers: evidence for
preserving target organs.
Clin Cardiol
2001;
24
; 183–190.
Drug Trends in Cardiology. ONTARGET
7.
proves telmisartan efficacy to ramipril in
cardiovascular protection of patients at high
risk and without heart failure.
Cardiovasc J
Afr
2008;
19
(2): 108.
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