D. Add amlodipine – Explanation

                               Calcium channel blockers are now preferred to thiazides in the treatment of hypertension

The 2011 NICE guidelines reflected the changing evidence base supporting the use of calcium
channel blockers in preference to thiazide-type diuretics in the management of hypertension.
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.

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

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 diarrh
• oea was occasionally seen
• only current role would seem to be in patients who are intolerant of more established
  antihypertensive drugs