Blood Pressure and Heart Medications from UK Doctors

Hypertension is defined as a sustained blood pressure at or above 140/90 mmHg in clinic, or at or above 135/85 mmHg on ambulatory or home monitoring.

It is the leading modifiable risk factor for cardiovascular disease, contributing to approximately 50% of strokes and 25% of myocardial infarctions in the UK.

Prevalence: An estimated 14.4 million adults in England have hypertension, yet approximately 5.5 million remain undiagnosed. Among those diagnosed, only 60% achieve target blood pressure.

This treatment gap represents a major preventable cause of cardiovascular morbidity and mortality.

Blood pressure classification (NICE 2019):

• Normal: below 120/80 mmHg
• Elevated: 120-139/80-89 mmHg (lifestyle modification recommended)
• Stage 1 hypertension: 140-159/90-99 mmHg (treat if target organ damage, cardiovascular disease, 10-year QRISK3 above 10%, or renal disease)
• Stage 2 hypertension: 160/100 mmHg or above (drug treatment offered to all)
• Stage 3 (severe): 180/120 mmHg or above (urgent same-day assessment required)

Target organ damage from sustained hypertension includes:

• Heart: Left ventricular hypertrophy, heart failure, coronary artery disease
• Brain: Ischaemic and haemorrhagic stroke, vascular dementia
• Kidneys: Hypertensive nephrosclerosis, chronic kidney disease progression
• Eyes: Hypertensive retinopathy with arteriovenous nipping and haemorrhages
• Arteries: Aortic aneurysm, peripheral vascular disease

The relationship between blood pressure and cardiovascular risk is continuous and graded.

Every 10 mmHg reduction in systolic pressure reduces stroke risk by 27%, heart failure by 28%, coronary events by 20%, and all-cause mortality by 13%, according to a meta-analysis of over 600,000 participants published in The Lancet.

Essential (primary) hypertension accounts for 90-95% of cases, driven by genetic predisposition interacting with dietary sodium, obesity, alcohol intake, and physical inactivity.

Secondary hypertension (5-10%) has identifiable causes including renal artery stenosis, primary aldosteronism, phaeochromocytoma, and Cushing's syndrome, and should be suspected in young patients, resistant hypertension, or sudden-onset severe hypertension.

NICE guideline NG136 provides a clear algorithm for antihypertensive drug selection based on age and ethnicity, reflecting differences in the underlying pathophysiology of hypertension across populations.

Step 1 treatment:

• Under 55 years, non-Black African/Caribbean: ACE inhibitor or ARB
• 55 years and over, or Black African/Caribbean of any age: Calcium channel blocker

ACE inhibitors (ramipril, lisinopril, enalapril, perindopril) block the conversion of angiotensin I to angiotensin II, reducing vasoconstriction and aldosterone secretion. Ramipril 1.

25-10 mg once daily is the most commonly prescribed. ACE inhibitors also reduce proteinuria and slow CKD progression, making them the preferred choice for patients with diabetes or renal disease.

Key considerations:

• Dry cough occurs in 10-15% of patients due to bradykinin accumulation — switch to an ARB if intolerable
• Hyperkalaemia risk: monitor serum potassium, especially with concurrent potassium-sparing diuretics or CKD
• Absolutely contraindicated in pregnancy (teratogenic) and bilateral renal artery stenosis
• Check renal function (eGFR and potassium) before starting, at 1-2 weeks, and after each dose change

ARBs (losartan, candesartan, irbesartan, valsartan) block the angiotensin II receptor directly.

They have a similar efficacy to ACE inhibitors without the cough side effect, making them the standard alternative. Candesartan 8-32 mg daily and losartan 50-100 mg daily are widely used.

Calcium channel blockers (CCBs) — amlodipine 5-10 mg daily is the most prescribed CCB in the UK. It dilates peripheral arterioles, reducing systemic vascular resistance.

CCBs are metabolically neutral (no adverse effects on glucose or lipids) and do not require renal monitoring.

CCB side effects include:

• Ankle oedema (10-30%, dose-dependent — not responsive to diuretics; reduces if combined with ACE/ARB)
• Flushing and headache (usually transient)
• Gingival hyperplasia (rare, more common with nifedipine)

Step 2: Combine ACE/ARB with CCB (or add a thiazide-like diuretic if CCB is not tolerated)

Step 3: ACE/ARB + CCB + thiazide-like diuretic (indapamide 1.5 mg MR or bendroflumethiazide 2.5 mg)

Step 4 (resistant hypertension): Add spironolactone 25 mg if potassium is 4.5 mmol/L or below; otherwise add alpha-blocker (doxazosin) or beta-blocker (bisoprolol). Consider specialist referral.

Most antihypertensives reach full therapeutic effect within 4-6 weeks, and NICE recommends reassessment at this interval for dose titration.

Home blood pressure monitoring (HBPM) is endorsed by NICE as the preferred method for confirming hypertension diagnosis and monitoring treatment response, alongside ambulatory blood pressure monitoring (ABPM).

Clinic measurements are subject to white-coat effect (elevated readings due to anxiety) in 15-30% of patients and may miss masked hypertension (normal clinic but elevated home readings) in 10-15%.

How to measure blood pressure correctly at home:

• Use a validated, upper-arm oscillometric monitor (check the British and Irish Hypertension Society list of validated devices)
• Sit quietly for 5 minutes before measuring, feet flat on the floor, arm supported at heart level
• Use the correct cuff size (standard cuff for arm circumference 22-32 cm; large cuff for 33-42 cm)
• Take two readings, 1 minute apart, and record both
• Measure in the morning (before medication) and evening for at least 4 days, ideally 7
• Discard the first day's readings and average the remaining values

Interpretation thresholds:

• Home average below 135/85 mmHg: at target
• Home average 135/85 mmHg or above: above target, treatment adjustment needed
• Home readings consistently below 120/75 mmHg on medication: consider dose reduction to avoid over-treatment

When monitoring is particularly important:

• At diagnosis: NICE requires ABPM or HBPM to confirm hypertension before initiating treatment (except in stage 3 / accelerated hypertension)
• After starting or changing medication: monitor weekly for the first month, then monthly until stable
• Suspected white-coat hypertension: clinic readings elevated but home readings normal
• Suspected masked hypertension: normal clinic readings but end-organ damage present
• Resistant hypertension: to confirm genuinely uncontrolled BP versus white-coat effect

Common pitfalls:

• Measuring immediately after exercise, caffeine, or smoking (all transiently elevate BP)
• Using wrist monitors, which are less accurate and position-sensitive
• Incorrect cuff size producing falsely high (cuff too small) or low (cuff too large) readings
• Measuring over clothing, which adds up to 50 mmHg artefact

Dr. Presc requires home blood pressure readings or recent GP-recorded readings as part of the consultation for antihypertensive prescriptions.

This ensures treatment decisions are based on accurate, representative measurements rather than single clinic values.

Non-pharmacological interventions form the foundation of blood pressure management at all stages of hypertension.

NICE recommends lifestyle measures for everyone with elevated blood pressure, regardless of whether medication is also prescribed.

The cumulative effect of multiple lifestyle changes can reduce systolic BP by 20-30 mmHg — equivalent to two or three antihypertensive drugs.

Sodium reduction is the single most effective dietary intervention.

Reducing sodium intake from the UK average of 8-9 g/day to the recommended 6 g/day (approximately one teaspoon of salt) lowers systolic BP by 4-5 mmHg in hypertensive patients.

Approximately 75% of dietary sodium comes from processed foods, not table salt. Reading food labels and reducing ready meals, bread, cheese, and processed meats makes the greatest impact.

The DASH diet (Dietary Approaches to Stop Hypertension) reduces systolic BP by 8-14 mmHg. Key components:

• 8-10 servings of fruits and vegetables daily
• Low-fat dairy products
• Reduced saturated fat and total fat
• Whole grains, nuts, and legumes
• Limited red meat and added sugars

Physical activity: 150 minutes per week of moderate-intensity aerobic exercise (brisk walking, cycling, swimming) reduces systolic BP by 5-8 mmHg.

Isometric resistance training (wall sits, handgrip exercises) has emerged as particularly effective, with recent meta-analyses showing 8-10 mmHg systolic reduction — potentially the most effective single exercise modality for BP lowering.

Weight loss: Each 1 kg of weight lost reduces systolic BP by approximately 1 mmHg.

For a person 20 kg overweight, this translates to a potential 20 mmHg reduction, often sufficient to avoid or reduce medication.

Alcohol reduction: Limiting intake to under 14 units per week lowers systolic BP by 3-4 mmHg. Heavy drinking (above 30 units/week) is associated with a 2-fold increase in hypertension prevalence.

Additional measures:

• Potassium-rich diet (bananas, potatoes, spinach, avocados) — lowers BP by 2-4 mmHg (avoid in CKD or if on ACE/ARB with high potassium)
• Stress reduction through mindfulness, yoga, or structured relaxation — modest but consistent BP benefit of 2-5 mmHg
• Caffeine: acute pressor effect, but regular consumers develop tolerance; no need to eliminate moderate consumption
• Sleep quality: treating obstructive sleep apnoea with CPAP reduces nocturnal and daytime BP by 3-6 mmHg

Antihypertensive treatment is typically lifelong, and regular monitoring ensures safety, efficacy, and adherence. NICE recommends structured follow-up for all patients on blood pressure medication.

Follow-up schedule:

• After initiation or dose change: review blood pressure at 4-6 weeks
• Once at target: review every 6-12 months
• Annual review includes: blood pressure, renal function (eGFR, potassium), cardiovascular risk reassessment (QRISK3), medication adherence, and side effect assessment

Blood tests required for monitoring:

• ACE inhibitors/ARBs: serum potassium and eGFR at baseline, 1-2 weeks after starting, and at each dose change. An eGFR fall of more than 25% or potassium rise above 5.5 mmol/L requires dose reduction or discontinuation.
• Thiazide diuretics: serum sodium, potassium, eGFR, urate, glucose, and HbA1c at baseline and within 4-6 weeks
• Spironolactone: potassium and eGFR monitored closely — hyperkalaemia risk is significant

Medication adherence is the most common cause of apparently resistant hypertension.

Studies using directly observed therapy and urinary drug metabolite testing reveal that 25-50% of patients prescribed antihypertensives are non-adherent.

• Simplify regimens to once-daily dosing where possible
• Use combination pills (e.g., perindopril/amlodipine or candesartan/amlodipine) to reduce pill burden
• Educate about the asymptomatic nature of hypertension — patients feel no different whether BP is controlled or not
• Address side effects proactively; ankle oedema with amlodipine and cough with ACE inhibitors are the leading causes of discontinuation

When to seek urgent advice:

• Blood pressure above 180/120 mmHg with symptoms (headache, visual disturbance, chest pain, breathlessness) — attend A&E immediately for accelerated hypertension assessment
• Signs of end-organ damage: new proteinuria, declining renal function, retinal haemorrhages
• Suspected secondary hypertension: young age of onset (under 40), sudden deterioration in previously well-controlled BP, hypokalaemia without diuretic use
• Adverse drug reactions: angioedema with ACE inhibitor (rare but life-threatening — presents as lip/tongue swelling, seek emergency care)

Dr. Presc provides repeat antihypertensive prescriptions for patients with established, stable hypertension. Home blood pressure readings are required for each renewal.

Patients with newly diagnosed or unstable hypertension are directed to their GP for in-person assessment, blood tests, and ABPM.