Hypertension is a persistent elevation of the blood pressure above normal values (≥140/90 mmHg) taken 2 to 3 times on at least two different occasions.
It is the commonest non-communicable disease in the world.
- Largely asymptomatic until complications arise (“silent killer”)
- Symptoms and signs of target organ diseases e.g. cardiac failure, stroke and chronic kidney disease
- Heart: Heart failure, ischaemic heart disease
- Brain: Stroke (ischaemic, hemorrhagic)
- Eye: Hypertensive retinopathy
- Kidney: Renal failure
- Peripheral artery disease
- Urinalysis; urine microscopy
- Electrolytes, Urea and Creatinine.
- Uric acid
- Fasting blood glucose
- Lipid profile
- Chest radiograph
- Others as may be indicated:
- Abdominal ultrasound
- Renal angiography
- Educate patient about disease and need for treatment adherence
- Reduce blood pressure to acceptable levels
- Prevent complications (primary, secondary, tertiary)
Non-drug treatment (lifestyle modification)
- Low salt diet: Not more than 1 level teaspoon of salt per day; No added salt; Avoid food preserved with salt
- Achieve/maintain ideal body weight (BMI 18.5-24.9 Kg/m²)
- Stop smoking years
- Reduce alcohol intake
- Regular exercise
- Reduce polysaturated fatty acid intake
Principles of drug treatment
- Treatment should be individualized
- Most patients will require combination chemotherapy using drug from different classes
- Fixed dose combination is desirable when 2 or more drugs are required
- Drugs with at least 24 hours duration of action to ensure once daily dosing
- Diuretics should be included unless contraindicated
- ACEI and beta blockers are ineffective when used as monotherapy in blacks
- Treat coexisting cardiovascular risk factors
- All patients require lifestyle modifications
Choice of drugs
- Bendroflumethiazide 2.5 – 10 mg orally daily
- Hydrochlorothiazide 12.5- 50 mg orally daily
- Hydrochlorothiazide/amiloride 25/2.5 mg daily
- Atenolol 25-100 mg orally daily
Calcium channel antagonists:
- Nifedipine retard 20-40 mg orally once or twice daily
- Amlodipine 2,5-10 mg orally once daily
Angiotensin converting enzyme inhibitors:
- Captopril 6.25-50 mg orally once or every 8 – 12 hours
- Lisinopril 2.5-20 mg orally once daily
Angiotensin receptor blockers:
- Losartan 50-100 mg orally daily
- Valsartan 80-160 mg daily
- Hydralazine 25-100 mg orally once daily or every 12 hours
- Prazosin 0.5-1 mg orally daily
Centrally acting drugs:
- Alpha methyldopa 250 – 500 mg orally twice, three or four times daily
- Treatment should be done by the experts. This involves the administration of antihypertensives by the parenteral route (usually intravenous hydralazine or sodium nitoprusside)
Notes on anti-hypertensive medicines
- Any of the five classes of major antihypertensive drugs can be used as first-line treatment. These are:
- Thiazide Diuretics
- Calcium Channel Blockers
- Angiotensin Converting Enzyme Inhibitors
- Angiotensin Receptor Blockers
- In the general black population, thiazide diuretics or calcium channel blockers, either as monotherapy or in some combination therapy, is preferrable.
- Angiotensin converting enzyme Inhibitors are not recommended as first-line drugs for uncomplicated hypertension in black patients.
- Dual therapy should be started earlier when the blood pressure exceeds 180/110 mmHg.
- Additional anti-hypertensive drugs should be used if target blood pressure levels are not achieved.
- Add-on drugs should be chosen from first-line choices bearing in mind compelling indications and contraindications.
Compelling indications for the choice of antihypertensives.
- Left ventricular hypertrophy: ACE-I or ARB, CCB preferably Amlodipine
- Renal dysfunction: ACE-I or ARB; Caution-if eGFR <15min/ml without renal replacement therapy
- Microalbuminuria: ACE-I or ARB
- Previous stroke: Any of the first-line drugs, especially ACE-I
- Coronary artery disease (Angina/Myocardial infarction): ACE-I or ARB, Beta-blocker, CCB.
- Heart failure: ACE-I or ARB, Cardio-selective B-Blockers- bisoprolol, metoprolol, carvedilol; Loop diuretics, Spironolactone in advanced heart failure
- Peripheral artery disease: CCB, ACE-I or ARB
- Diabetes mellitus: ACE-I or ARB
- Atrial fibrillation: ARB or ACE-I or
- Gout: Thiazide diuretics
- Beta-blockers: Asthma, 2 and 3 AV block
- Heart failure: CCB
- Bilateral renal artery stenosis and hyperkalaemia: ACE-I or ARB
- Patient/caregiver education
Notable adverse drug reactions, caution and contraindications
Angiotensin converting enzyme inhibitors, angiotensin receptor blockers:
- dry cough with ACEIS.
Alpha methyldopa, thiazides and potentially other anti-hypertensive drugs may cause erectile dysfunction.
Alpha methyl dopa may cause postural hypotension.
SLE-like syndrome: hydralazine.
Do not use beta blockers in asthmatics and heart failure
- Weight reduction
- Exercise moderately and regularly
- Public education
- Individual and Population based approaches
- Advocacy for the positive lifestyle change
- Target blood pressure: BP<140/90 mmHg for general population, BP < 130/80 mmHg for patients with diabetes or end stage renal
Hypertension in pregnancy
- ACEI and ARB are terratogenic, contraindicated in pregnancy & to be used with caution in women in reproductive age group.
- Alpha methyl dopa, hydralazine, calcium channel blockers are safe in pregnancy.
- Diuretics are relatively safe.
Refer the following categories of hypertensive patients to an
- Those not achieving the target blood pressure (BP) level after several months of treatment
- Those on three or more anti-hypertensive drugs, yet have poor BP control
- Those with worsening of BP over a few weeks or months
- Those with plasma creatinine levels above the upper limit of normal
- Those with diabetes mellitus
- Those with multiple risk factors (diabetes, dyslipidaemia, obesity,
family history of heart disease)
- Those not on diuretics but have persistently low potassium on
repeated blood tests
- All children, young adults and pregnant women with elevated BP