Hypertension

The following is based on NICE guidance 136, Hypertension in Adults: Diagnosis & Management. The threshold for diagnosis of hypertension is 140/90 (Office blood pressure) or 135/85 mmHg (Ambulatory BP Monitoring or Home BP Monitoring).

Sections on this page:

Types of measurement
Monitoring blood pressure
Staging of hypertension
Targets for BP control
Drug management of hypertension

Types of measurement

Pros and cons of the various BP measurement modalities are discussed below

Office Blood Pressure Measurement (OBPM)
Equipment required	Electronic or calibrated analogue sphygmomanometer. Direct manual measurement is not recommended unless the patient has an arrhythmia (e.g. atrial fibrillation). More information can be found here.
Technique	Ideally have the patient in a relaxed, temperate setting, with the person quiet and seated, and their arm outstretched and supported. Check the patient does not have an irregular heartbeat; if they do, perform manual BP measurement and consider obtaining an ECG Attach the cuff to the patient’s arm in advance. Ensure the patient’s brachial artery and heart are at the same level. Take a measurement. If the BP is over 140/90, repeat the measurement at 5 minutes. If the two measures are substantially different, take a 3^rd measure and use the mean of the last 2 measurements. Measure BP in both arms; if the difference is >15mmHg, repeat the measurements. If the BP is consistently higher in one arm, use that for all future measurements.
Pros	Easily accessed at short notice Cheap/free Gives an instant result in front of the patient
Cons	Susceptible to white-coat effect Crude measure of patient’s true blood pressure Is rarely performed in a “relaxed temperate setting”, with 5 minutes rest beforehand
Notes	OBPM can generally be relied upon if normal (masked hypertension is rare), should not be relied upon for the diagnosis of hypertension NICE guidance recommends confirming hypertension with either Home or 24h Ambulatory BP measurement.

Ambulatory Blood Pressure Measurement (ABPM)
Equipment required	24h Ambulatory monitor + recording device
Technique	Performed in secondary care usually. Referral details available here.
Pros	Gold-standard for measurement of blood pressure Identifies cases of white-coat hypertension, masked hypertension, and nocturnal ‘non-dippers’ Gives a clear answer
Cons	Expensive Time-consuming Relies on patient attending secondary care to pick up/return device Some patients may not be able to tolerate the cuff inflating/deflating repeatedly, including through the night Impractical for long-term monitoring
Notes	Some GP practices may also have ABPM monitors that they can loan out to patients, mitigating some of the cons listed above. Some patient groups should have ABPM in order to assess their nocturnal dipping status: diabetes, CKD, sleep apnoea, endocrine hypertension and autonomic dysfunction.

Home Blood Pressure Measurement (HBPM)
Equipment required	Automated BP Monitor; the BIHS keeps a list of approved validated monitors, which can be purchased from as little as £15. The Omron M2 is a cheap and basic option.
Technique	We have developed a HBPM information sheet and monitoring form for patients to use, which includes details on optimal technique: see here.
Pros	Cheap Gives accurate results (if done correctly, on a par with ABPM) Not susceptible to the white coat effect & identifies masked hypertension Suitable for long term monitoring
Cons	Patient has to fund initial cost of purchase Relies on patient motivation and use of optimal technique for accurate monitoring Patients can fail to record enough readings to allow accurate interpretation Does not assess for nocturnal ‘dipping’
Notes	This is the recommended modality for monitoring of hypertension, but does require patient engagement

Monitoring blood pressure

HBPM is the recommended method, due to its low cost and accuracy. In patients who cannot perform HBPM accurately, or who cannot afford a monitor, OBPM can be used, but is not advised if HBPM is possible.

ABPM can be used when the patient has persistently high OBPM readings despite increases to their antihypertensive medication regimen, as the white coat effect may be masking adequate BP control.

Telemonitoring (e.g. Scale-up BP) is also an option in most NHS Lothian GP practices. See here for details.

Staging of Hypertension

Management of hypertension should always incorporate non-drug management, as this is likely to have a much greater reduction on the patient’s overall cardiovascular risk. Recommend lifestyle modification for all patients.

Recommended introduction of drug and non-drug management according to severity:

Stage	Systolic BP (mmHg)	Diastolic BP (mmHg)	Recommendation
I	140–159	90–99	Lifestyle advice only (reassess at appropriate interval) Consider drug treatment if: Target organ damage (retinopathy, nephropathy, cardiac) Cardiovascular disease Renal disease Diabetes mellitus QRISK3/ASSIGN score >10% Also consider drug treatment for patients aged >80 with SBP >150.
II	160–179	100–119	Lifestyle advice Drug treatment
III	180+	120+	Lifestyle advice Drug treatment In addition, look for end-organ damage/secondary hypertension and consider referral to specialist care

NB: for ABPM/HBPM the targets are 5mmHg lower, i.e. 135 instead of 140

Targets for BP control

The following are taken from NICE guidance 2019-2020:

Patient group	Target BP (mmHg) NB: for ABPM/HBPM the targets are 5mmHg lower, i.e. 135 instead of 140
Adults <80 years	140/90
Adults ³80 years	150/90
Type 1 diabetic patients	135/85 If 2+ features of metabolic syndrome or albuminuria, target is 130/80
Chronic kidney disease patients	140/90 If proteinuria present, target is 130/80
Stroke patients	Systolic BP <130

Drug management of Hypertension

The recommended order in which medications are started is in the flowchart below (reproduced from NICE guidance 136).

NB:

Patients with type 1 diabetes should also be started on ACEi/ARB for first line therapy.
Amiloride can be used in place of spironolactone if better tolerated

Link to Lothian Hypertension guidance is available. Short notes on the drugs recommended in the Lothian Joint Formulary are below.

Lisinopril
Type/class	ACE inhibitor
Dosage	Start: 10mg daily Increase: Double dosage (10mg, 20mg, 40mg) Max: 40mg daily
Pharmacokinetic issues	Bioavailability: 25% Half-life: 12h Eliminated unchanged in urine
Common Adverse Drug Reactions	Postural hypotension, dizziness, cough, hyperkalaemia; less commonly angioedema (more so in black patients)
Significant Interactions	Spironolactone/amiloride – hyperkalaemia Lithium – increased lithium levels NSAIDs – renal impairment
Notes	First-dose hypotension uncommon Due to the above increased risk of angioedema, some guidelines advise using ARBs preferentially in black patients Recheck creatinine after initiation/dosage increase (a rise in creatinine of up to 25% is acceptable)
Alternatives	Ramipril (2.5mg/day, titrate to max. 10mg/day) Candesartan

Candesartan
Type/class	Angiotensin Receptor Blocker
Dosage	Start: 8mg daily (4mg if risk of renal injury) Increase: Double dosage (8mg, 16mg, 32mg) Max: 32mg daily
Pharmacokinetic issues	Bioavailability: 15% Half-life: 9h Elimination: 33% renal / 66% stool
Common Adverse Drug Reactions	Abdominal/back pain, dizziness
Significant Interactions	Spironolactone/amiloride – hyperkalaemia Lithium – increased lithium levels NSAIDs – renal impairment
Notes	First-dose hypotension uncommon Recheck creatinine after initiation/dosage increase (a rise in creatinine of up to 25% is acceptable)
Alternatives	ACE inhibitors Losartan (25mg/day, titrate to max. 100mg/day)

Amlodipine
Type/class	Calcium channel blocker (dihydropyridine)
Dosage	Start: 5mg daily Max: 10mg daily
Pharmacokinetic issues	Bioavailability: 65-80% Half-life: 35-50h Elimination: 60% renal
Common Adverse Drug Reactions	Leg swelling (common reason for discontinuation) GI disturbance Flushing Rash Dizziness
Significant Interactions	P450 Inducing medication – lower drug levels of amlodipine P450 Inhibiting medication – higher drug levels of amlodipine Simvastatin – increased level of simvastatin
Notes	If stopped because of leg swelling, consider Lercanidipine Some formulations are scored, allowing reduction to 2.5mg daily if this is better tolerated
Alternatives	Lercanidipine (start 10mg/day; titrate to max. 20mg/day) Diltiazem/verapamil

Indapamide
Type/class	Thiazide-like diuretic
Dosage	Dose is 2.5mg once daily, or 1.5mg of the modified-release preparation Choose lowest-cost formulation
Pharmacokinetic issues	Bioavailability: 100% Half-life: 14-18h Elimination: 70% renal; 23% GI tract
Common Adverse Drug Reactions	Dry mouth GI disturbance Hypokalaemia Erectile dysfunction Rash
Significant Interactions	Amiodarone – arrhythmia Lithium – Lithium toxicity
Notes	NICE guidance recommends thiazide-like diuretics (Indapamide) over thiazides (Bendroflumethiazide) Choose lowest-cost formulation
Alternatives	Bendroflumethiazide

Bendroflumethiazide
Type/class	Thiazide diuretic
Dosage	Start: 2.5mg daily Increase: 2.5mg increments Max: 10mg daily
Pharmacokinetic issues	Bioavailability: 100% Half-life: 3.5h Elimination: 30% urine; 70% metabolised
Common Adverse Drug Reactions	Dry mouth GI disturbance Hypokalaemia Erectile dysfunction
Significant Interactions	Amiodarone – arrhythmia Lithium – Lithium toxicity
Notes	Normal dose is 2.5mg, but dose can be increased to 5mg daily before addition of another agent NICE guidance recommends thiazide-like diuretics (Indapamide) over thiazides (Bendroflumethiazide)
Alternatives	Indapamide

Spironolactone
Type/class	Potassium-sparing diuretic
Dosage	Start: 25mg daily Increase: 25mg increments Max: 100mg daily
Pharmacokinetic issues	Bioavailability: 75% Half-life: 1.4h Elimination: Hepatic  urine/bile
Common Adverse Drug Reactions	Hyperkalaemia Renal impairment Headache Weakness GI disturbance Erectile dysfunction Gynaecomastia
Significant Interactions	Ciclosporin – hyperkalaemia Lithium – Lithium toxicity Digoxin – Digoxin toxicity
Notes	Frail elderly patients can start at 12.5mg daily
Alternatives	Amiloride (starting dose 10mg daily, max. 20mg daily), Eplerenone

Bisoprolol
Type/class	Beta-adrenoceptor antagonist
Dosage	Start: 1.25 – 2.5mg daily (lower dose in elderly) Increase: 2.5mg increments Max: 20mg daily (10mg in heart failure)
Pharmacokinetic issues	Bioavailability: 90% Half-life: 10-12h Elimination: 50% hepatic / 50% renal
Common Adverse Drug Reactions	Dizziness Headache Sleep disturbance Bradycardia Cool/numb peripheries GI disturbance Weakness
Significant Interactions	Verapamil/Diltiazem – heart block Theophylline/Aminophylline – bronchospasm Mefloquine – bradycardia
Notes
Alternatives	Atenolol, Carvedilol, Metoprolol

Doxazosin
Type/class	Alpha-1-adrenoceptor antagonist
Dosage	Start: 1mg daily Increase: Double every 1-2 weeks Max: 16mg daily
Pharmacokinetic issues	Bioavailability: 66% Half-life: 22h Elimination: Hepatic
Common Adverse Drug Reactions	Postural hypotension (particularly on initiating therapy) Weakness Chest pain Oedema Flu-like illness
Significant Interactions	Sildenafil – hypotension
Notes	Alpha-blockers should generally be used as a last resort.
Alternatives	Prazosin, Terazosin

This article was published on 22 Sep, 2021