CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 1, January/February 2011
46
AFRICA
(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.
Choosing telmisartan over other
ARBs: the evidence
Pharmacological evidence of telmisar-
tan’s efficacy in terms of blocking the
angiotensin II type 1 receptor is accu-
mulating. A recent Japanese study of
constructed models of ARB molecules
has found that the delta lock structure
of telmisartan offers a superior fit to the
receptor, compared to the other ARBs.
7
This fit may explain the highest lipo-
philicity, the greatest volume distribu-
tion and the strongest binding affinity
of telmisartan to the type 1 receptor
when compared to other ARBs. This
receptor affinity is likely to contribute
to the clinical evidence for telmisartan’s
greater blood pressure lowering compared
to other ARBs, particularly losartan and
valsartan.
8-10
Choosing the combination of
telmisartan + HCTZ
Blood pressure control in some patients
is ineffective with just monotherapy, and
combinations of antihypertensive agents
offer an opportunity to intensify treatment
without adding to the pill load.
In African patients where there may be
evidence of less involvement of the RAAS
system, the initial choice in the public
sector is often a diuretic. A recent study
in KwaZulu-Natal looked at prescribing
habits in 54 public-sector hospitals in this
region and compared this to supply data
and to the SA Hypertension Guidelines.
11
It found that the most commonly used
agents were diuretics (42%) and ACE
inhibitors (27%) and that these prescrip-
tions correlated well with supply data
for these frequently used medications.
Calcium channel blockers and beta-block-
er usage was 6% each.
Clearly, as ARBs become more avail-
able in the public sector, the opportunities
offered by the combination of telmisartan
and HCTZ should receive wider use.
Publicity given to the lack of dialysis
facilities for kidney failure in the public
sector in South Africa should also add to
the imperative to improve hypertension
control.
The blood pressure of patients who
are at particular risk of cardiovascular
disease, such as those who are obese or
have type 2 diabetes, are often difficult
to control. The SMOOTH study (Study
of Micardis on Obese/Overweight Type
2 diabetes patients with HypErtension)
showed the superior effect of telmisartan
80 mg plus HCTZ 12.5 mg, compared
to valsartan 160 mg plus HCTZ 12.5 mg
over 24 hours and especially in the early
morning period.
12
The elderly patient also frequently
falls into a difficult-to-treat category.
A study in this patient group recruited
1 000 patients over the age of 60 years
with isolated systolic hypertension and
compared control between telmisartan
plus HCTZ and amlodipine plus HCTZ.
Referred to as the ACTOS study,
13
this
showed the generally more effective blood
pressure-lowering action of telmisartan in
the last six hours of the dosing interval,
and more effective systolic blood pres-
sure lowering throughout the 24-hour
treatment period and in the morning and
evening periods.
A recent evaluation of more than
48 000 patients taking either a diuretic
of a fixed-combination antihypertensive
with a diuretic showed greatly improved
compliance with the fixed combination
(32 vs 50%, respectively). The fixed
combination of the ARB/HCTZ achieved
improved persistence and adherence to
therapy even over the ACEI/HTCZ.
The wider use of telmisartan in moder-
ate hypertension as an early therapy can
be substantiated at both a pharmacologi-
cal and clinical level.
J Aalbers, Special Assignments Editor
1. Rayner B, Schoeman HS. Across sectional
study of blood pressure control in hyperten-
sive patients in general practice (the I-Target
study).
Cardiovasc J
2009;
20
: 224–227.
2. Coleman R,
et al
. Non-communicable disease
management in resource-poor settings: a
primary care model from rural South Africa.
Bull Wld Hlth Org
1998;
76
(6): 633–640.
3. Galzerano D, Capogrosso C, Di Michele S,
Galzerano A,
et al
. New standards in hyper-
tension and cardiovascular risk management:
focus on telmisartan.
Vasc Hlth Risk Mgmt
2010;
6
: 113–133. P10-02804.
4. White WB, Giles T, Bakris GL,
et al
.
Measuring the efficacy of antihypertensive
therapy by ambulatory blood pressure moni-
toring in theprimary care setting.
Am Heart J
2006;
151
: 176–184.
5. How do recent developments affect the
angiotensin receptor blockers as a class?
Cardiovasc J Afr
2009;
20
(2): 145.
6. Gosse P, Neutel JM, Schumacher H,
et al
.
The effect of telmisartan and ramipril on
early morning blood pressure surge: a pooled
analysis of two randomized clinical trials.
Blood Press Monit
2007;
12
: 141–147.
7. Ohno K, Amano Y, Kakuta H, Niimi T,
Takakura S, Orita M, Miyata K,
et al
.
Unique “delta lock” structure of telmisartan
is involved in its strongest binding affinity
to angiotensin II type 1 receptor.
Biochem
Biophys Res Commun
2011; Jan 7: 404–407.
Epub 2010 Dec 3.
8. Mallion JM, Siché JP, Lacourcière Y; The
Telmisartan Blood Pressure Monitoring
Group. ABPM comparison of the antihyper-
tensive profiles of the selective angiotensin II
receptor antagonists telmisartan and losartan
in patients with mild-to-moderate hyperten-
sion.
J Hum Hypertens
1999;
13
: 657–664.
9. Ding PY, Chu KM, Chiang HT,
et al
. A
double-blind ambulatory blood pressure
monitoring study of the efficacy and toler-
ability of once-daily telmisartan 40 mg in
comparison with losartan 50 mg in the treat-
ment of mild-to-moderate hypertension in
Taiwanese patients.
Int J Clin Pract Suppl
2004;
58
: 16–22.
10. Lacourcière Y, Krzesinski JM, White WB,
et al
. Sustained antihypertensive activity of
telmisartan compared with valsartan.
Blood
Press Monit
2004;
9
: 203–210.
11. Pillay T, Smith AJ, Hill SR. A comparison of
two methods for measuring anti-hyperten-
stive drug use: concordance of use with SA
standard treatment guidelines.
Bull Wld Hlth
Org
2009;
87
: 466–471.
12. Sharma A, Davidson J, Koval S,
et al
.
Telmisartan/hydrochlorothiazide versus vals-
artan/hydrochlorothiazide in obese hyper-
tensive patients with type 2 diabetes: the
SMOOTH study.
Cardiovasc Diabetol
2007;
6
: 28.
13. Neldam S, Edwards C. Telmisartan plus
HCTZ vs amlodipine plus HCTZ in older
patients with systolic hypertension: results
from a large ambulatory blood pressure
monitoring study.
Am J Geriatr Cardiol
2006;
16
: 151–160.
