E. Amlodipine – Explanation
ACE inhibitors have reduced efficacy in black patients and are therefore not used first-line
Hypertension: diagnosis and management
NICE published updated guidelines for the management of hypertension in 2011. Some of the key
changes include:
- classifying hypertension into stages
- recommending the use of ambulatory blood pressure monitoring (ABPM) and home blood pressure
monitoring (HBPM) - calcium channel blockers are now considered superior to thiazides
- bendroflumethiazide is no longer the thiazide of choice
Blood pressure classification
This becomes relevant later in some of the management decisions that NICE advocate.
| Stage 1 hypertension | Clinic BP >= 140/90 mmHg and subsequent ABPM daytime average or HBPM average BP >= 135/85 mmHg |
| Stage 2 hypertension | Clinic BP >= 160/100 mmHg and subsequent ABPM daytime average or HBPM average BP >= 150/95 mmHg |
| Severe hypertension | Clinic systolic BP >= 180 mmHg, or clinic diastolic BP >= 110 mmHg |
Diagnosing hypertension
If a BP reading is >= 140 / 90 mmHg patients should be offered ABPM to confirm the diagnosis.
Patients with a BP reading of >= 180/110 mmHg should be considered for immediate treatment.
Ambulatory blood pressure monitoring (ABPM)
- at least 2 measurements per hour during the person’s usual waking hours (for example, between
08:00 and 22:00) - use the average value of at least 14 measurements
If ABPM is not tolerated or declined HBPM should be offered.
Home blood pressure monitoring (HBPM)
- for each BP recording, two consecutive measurements need to be taken, at least 1 minute apart
and with the person seated - BP should be recorded twice daily, ideally in the morning and evening
- BP should be recorded for at least 4 days, ideally for 7 days
- discard the measurements taken on the first day and use the average value of all the remaining
measurements
Managing hypertension
ABPM/HBPM >= 135/85 mmHg (i.e. stage 1 hypertension)
- treat if < 80 years of age and any of the following apply; target organ damage, established cardiovascular disease, renal disease, diabetes or a 10-year cardiovascular risk equivalent to 20% or greater
ABPM/HBPM >= 150/95 mmHg (i.e. stage 2 hypertension)
- offer drug treatment regardless of age
For patients < 40 years consider specialist referral to exclude secondary causes.
Step 1 treatment
- patients < 55-years-old: ACE inhibitor (A)
- patients > 55-years-old or of Afro-Caribbean origin: calcium channel blocker
Step 2 treatment
- ACE inhibitor + calcium channel blocker (A + C)
Step 3 treatment
- add a thiazide diuretic (D, i.e. A + C + D)
- NICE now advocate using either chlorthalidone (12.5-25.0 mg once daily) or indapamide (1.5 mg
modified-release once daily or 2.5 mg once daily) in preference to a conventional thiazide diuretic
such as bendroflumethiazide
NICE define a clinic BP >= 140/90 mmHg after step 3 treatment with optimal or best tolerated doses
as resistant hypertension. They suggest step 4 treatment or seeking expert advice
Step 4 treatment
- consider further diuretic treatment
- if potassium < 4.5 mmol/l add spironolactone 25mg od
- if potassium > 4.5 mmol/l add higher-dose thiazide-like diuretic treatment
- if further diuretic therapy is not tolerated, or is contraindicated or ineffective, consider an alpha- or
betablocker
If BP still not controlled seek specialist advice.
Blood pressure targets
| Clinic BP | ABPM / HBPM | |
| Age < 80 years | 140/90 mmHg | 135/85 mmHg |
| Age < 80 years | 150/90 mmHg | 145/85 mmHg |
New drugs
Direct renin inhibitors
- e.g. Aliskiren (branded as Rasilez)
- by inhibiting renin blocks the conversion of angiotensinogen to angiotensin I
- no trials have looked at mortality data yet. Trials have only investigated fall in blood pressure. Initial
trials suggest aliskiren reduces blood pressure to a similar extent as angiotensin converting enzyme
(ACE) inhibitors or angiotensin-II receptor antagonists - adverse effects were uncommon in trials although diarrhoea was occasionally seen
- only current role would seem
