Cardiovascular Journal of Africa: Vol 25 No 6 (November/December 2014)

43 / 66

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 25, No 6, November/December 2014 AFRICA 293
Once the issues relating to lifestyle, adherence to therapy,
white coating, etc. outlined in Table 7 have been satisfactorily
managed, then consideration should be given to the addition
of the fourth- and fifth-line drug. Currently spironolactone
(25–50 mg only) with careful monitoring of serum potassium,
beta-blockers and/or long-acting doxazasin is recommended.27,28
Other choices include direct-acting vasodilators (hydralazine,
minoxidil), or centrally acting drugs (methyldopa, moxonidine,
reserpine).
Initial studies of renal denervation in patients with resistant
HTN showed very promising results.29,30 The recent publication
of the Simplicity 3 study showing no significant effect on BP
compared to sham procedure, the place of renal denervation in
the treatment of resistant HTN remains to be established and is
not supported by this guideline.31
Special considerations for hypertension in
certain populations
Blacks and Asians
Blacks are more prone to complications of stroke, heart failure
and renal failure, while the incidence of coronary heart disease,
although increasing in frequency, is less common compared with
that in whites and Asians.32 The prevalence of diabetes mellitus
and the metabolic syndrome is higher in Asians compared to
other racial groups.33
Compared to whites, blacks respond poorly to ACEI and
β-blockers as monotherapy, but this difference disappears once
these drugs are combined with diuretics. Overall, CCBs show
the most consistent response in blacks compared to other classes
of drugs used as monotherapy.23,34 However there is a higher
incidence of angioedema in blacks treated with an ACEI.35
Hypertension in children and adolescents36,37
HTN in children is an important issue beyond the scope of
this guideline. In adolescents, the HTN is increasingly linked
to obesity and affects up to 10% of people between the ages
of 15 and 25 years.38 The international trend of poor diet and
lack of exercise in children is leading to an epidemic of obesity,
with the early onset of HTN and even type 2 diabetes. The early
recognition of HTN in these adolescents will be an important
motivation for both children and parents to institute important
lifestyle changes.
HIV/AIDS
There are an estimated 5.8 million people living with HIV in
South Africa. The co-existence of HIV with HTN and diabetes
is increasing, and patients should be screened for associated
glomerulonephritis.39 Prolonged highly active antiretroviral
therapy (HAART) is associated with a higher prevalence of
systolic HPT,40 and it is essential that BP is monitored in patients
receiving HAART.
Two of the three major classes of antiretroviral drug, the
protease inhibitors and the non-nucleoside reverse transcriptase
inhibitors, are involved in many drug interactions by inhibiting
or inducing the key hepatic enzyme system, cytochrome P450.
CCBs are the major class of antihypertensives affected by such
drug interactions, leading to inhibition or induction of their
metabolism.41,42 This results in either an enhanced or loss of
antihypertensive efficacy.
Disclaimer
This national clinical guideline is a reference and educational
document. The SAHS accepts no responsibility or liability
arising from any information contained in or any error of
omission from the protocol or from the use of any information
contained in it.
References
1. Kandala NB, Tigbe W, Manda SO, Stranges S. Geographic variation of
hypertension in sub-Saharan Africa: a case study of South Africa. Am J
Hypertens 2013; 26(3): 382–391.
2. Seedat YK, Rayner BL. South African hypertension guideline 2011. S
Afr Med J 2012; 102: 59–83.
3. Flack JM, Sica DA, Bakris G, et al. International Society of
Hypertension in Blacks. Management of high blood pressure in blacks:
an update of high blood pressure in blacks consensus statement.
Hypertension 2010; 56: 780–800.
4. Hackam DG, Quinn RR, Ravani P, et al.: Canadian Hypertension
Education Program. The 2013 Canadian Hypertension Education
Program recommendations for blood pressure measurement, diagnosis,
assessment of risk, prevention, and treatment of hypertension. Can J
Cardiol 2013; 29(5): 528–542.
5. Mancia G, Laurent S, Agahiti-Rosei, et al. Reappraisal of European
guidelines on hypertension management: a European Society of
Hypertension Task Force Document. J Hypertens 2009; 27: 2121 – 2158
6. National Clinical Guideline Centre. CG127 Hypertension: NICE
guideline. The clinical management of primary hypertension in adults.
(accessed
2 May 2014).
7. Weber MA, Schiffrin EL, White WB, et al. Clinical practice guidelines
for the management of hypertension in the community. A statement by
the American Society of Hypertension and the International Society of
Hypertension. J Hypertens 2013; 32: 3–15.
8. James PA, Oparil S, Carter BL, et al. 2014 Evidence-based guideline for
the management of high blood pressure in adults. Report from the panel
members appointed to the eighth joint national committee (JNC 8). J
Am Med Assoc 2014; 311(5): 507–520
9. Mancia G, Fagard R, Narkiewicz K, et al. 2013 ESH/ESC guidelines for
the management of arterial hypertension. The task force for the manage-
ment of arterial hypertension of the European Society of Hypertension
(ESH) and of the European Society of Cardiology (ESC). J Hypertens
2013; 31: 1281–1357.
10. Tirosh A, Afek A, Rudich A, et al. Progression of normotensive adoles-
cents to hypertensive adults. A study of 26 980 teenagers. Hypertension
2010; 56: 203–209.
11. O’Brien E, Asmar R, Beilin L, et al., on behalf of the European Society
of Hypertension working group on blood pressure monitoring. Practice
guidelines of the European Society of Hypertension for conventional,
ambulatory and home blood pressure measurement. J Hypertens 2005;
23: 697–701.
12. Bur A, Herkner H, Vlcek M, et al . Classification of BP levels by ambula-
tory BP in hypertension. Hypertension 2002; 40: 817–822.
13. Lovibond K, Jowett S, Barton P, et al. Cost-effectiveness of options for
the diagnosis of high blood pressure in primary care: a modelling study.
Lancet 2011: 378: 1219–1130.