Hypertension high blood pressure



 Hypertension comes from two words: hyper meaning above normal
and tension meaning pressure.

Hypertension is defined as a persistent rise in blood pressure above what is considered normal for the Person’s age (140/90mmHg).

A Person qualifies to be having hypertension (high blood pressure) when
either diastolic or systolic pressure or both consistently rises above normal when measured on at least 3 separate visits.

Blood pressure: This is the pressure exerted when blood flows into the arteries. It is measured in mmHg using a sphygmomanometer (blood pressure machine)

Diastolic pressure; This is the pressure exerted on the arteries when the heart relaxes

Systolic pressure: This the pressure exerted on the arteries when the heart contracts

Classification of blood pressure

The blood pressure in adults is classified as shown in the table below. The purpose of this classification is to aid proper intervention in the management of hypertension

Bp classification 

Systolic Bp                                     Diastolic         Bp(mmHg)


<120                    and                     <80

Pre hypertension

120 – 139             or                        80 – 89 

Stage 1 hypertension 

140 -159             or                        90 – 99

Stage 2 hypertension 

≥160                     or                       ≥100 

Isolated systolic hypertension 

≥140                    and                     <90

Proper Measurement of blood pressure 

In order to obtain appropriate results, the following must be followed:

  • Measure the blood pressure using  the right blood pressure machine i.e. the cuff should  not be too small or too large for the patient 
  • Allow the patient to rest for at least 5 to 10 minutes before measuring the blood pressure since exercise increases the blood pressure
  • The patient should not be talking while the blood pressure is being measured since wrong results (higher) may be obtained when the patient talks 
  • The arm of the patient should be positioned at the level of the heart
  • At least 2 – 3 measurements should be made at different visits for those with pre hypertension  and stage 1 hypertension before the patient is confirmed to be having hypertension 
  • Inform the patient of his or her blood pressure results and what they mean
  • Record the patient’s blood pressure on the medical form and a copy of results should be given to the patient

Types of hypertension 

Hypertension is divided into two depending on the cause:

  • Essential (primary) hypertension 
  • Secondary hypertension 
Essential hypertension 

This is the elevation of blood pressure without a known cause It contributes up to 90% of all cases of hypertension seen in Uganda.

It was called essential hypertension because they thought elevation of blood pressure in elderly patients was necessary to overcome peripheral resistance created by the rigidity of blood vessels caused by aging. 

Risk factors for hypertension 

Any person may develop hypertension but the following categories of people with the risk factors listed below have higher chances of developing hypertension 

  • Family history (close relative like father, mother, or sister) with hypertension or cardiovascular disease. 
  • Patients with diabetes mellitus 
  • People who are inactive all the time  (lack of exercise)
  • Persons who are overweight or obese (body mass index) ≥30kg/m2
  • People who   smoke cigarette 
  • Advancing age ( people above 60yrs )
  • Patients whose cholesterol (fat content in the blood) level is higher than normal.
Secondary hypertension 

This is the elevation of blood pressure due to a known cause. The cause may be any of the following:

  • Kidney disease 
  • Use of drugs such as steroids, oral contraceptives.
  • Pregnancy (pre eclampsia and eclampsia)
  • Obstructive sleep apnoea
  • Coarctation (narrowing of the aorta)
  • Diabetic renal disease

Note: secondary hypertension is treated by eliminating or treating the cause but sometimes drugs may be used to control the blood pressure

Management of Hypertension 

Non pharmacological measures 

  • Educate the patient  and care giver about hypertension and its chronic nature.
  • Advise the patient to lose weight if he /she is overweight or obese
  • Encourage the  patient to do regular exercise such as walking ,riding a bicycle, jogging etc for at least 30 minutes per day and for at least 5 days in a week
  • Tell the patient to quit smoking if she or he does as smoking reduces the effectiveness of drugs for hypertension
  • Encourage the patient to have a diet containing more of fruits and vegetables. 
  • Advise the patients  who  drink alcohol  to take it in  moderate quantities i.e. 2 bottles of beer per  day since excessive amount rises the blood pressure
  • Advise the patient to eat food containing less salt (low sodium intake)
  • Advise the patient to avoid eating food containing saturated fats

Drug therapy

Drug treatment is recommended for those patients who have not responded to non drug measured and for those who report when the blood pressure is already very high. One drug (monotherapy) is recommended initially for patients with mild hypertension.

In case of poor response another drug may be added or substituted 

Patients who present when already in stage 2 may be started on two drugs at once in lower doses then adjusted depending on the response.

Choice of antihypertensive 

When choosing a drug for treating hypertension, consider the following in order to safely use the drugs and effective control of blood pressure.

  •  Patients with other existing diseases or conditions such as pregnancy asthma, diabetes, heart failure, pregnancy, and angina pectoris. This is because some antihypertensive are not recommended to be used in some of the above conditions.
  • Affordability and accessibility of the medicine by the patients 
  • Establish whether the patient is allergic to the drug or not
  • Establish the Presence of target organ damage 

Choice of antihypertensive in different conditions 


Recommended antihypertensive 


1st choice 

2nd choice 


Methyldopa (Aldomet)

Atenolol ,Nifedipine 

Diabetes  mellitus  

Captopril ,Lisinopril 

Nifedipine ,Amlodipine 


Amlodipine, Nifedipine 


Preeclampsia or eclampsia of pregnancy

Hydralazine (Apresoline)


Angina pectoris 

Nifedipine ,Amlodipine 

Atenolol ,Propranolol

Heart failure 

Frusemide, Lisinopril, Captopril


Resistant hypertension 

This is the persistent elevation of blood pressure above 140/90mmHg despite the use of 3 or more appropriate drug combination including a diuretic at full doses


  • Patients above 60 years 
  • Poor drug compliance(taking the drugs wrongly) 
  • Continuous presence of risk factors such as smoking ,excessive alcohol intake and obesity
  • Concurrent use of drugs that elevate blood pressure for example flu (common cold) preparations(decongestants),painkillers like diclofenac
  • Presence of secondary causes of hypertension  for example  kidney failure

Malignant hypertension, hypertensive emergency, hypertensive urgency

Malignant hypertension 

Malignant hypertension is a condition characterized by sudden severe rise in blood pressure resulting into small vessel damages

Clinical presentation include confusion, headache, visual loss and comma

It is a medical emergency that requires hospital admissions and rapid control of blood pressure over 12 to24 hours to normal level

Hypertensive emergency 

This is severe elevation of   blood pressure more than 180/120mmHg) with signs of damage to target organs such as the brain and kidney.

The patient must be admitted in the hospital if possible in intensive care unit and pressure must be lowered immediately to prevent damage to the kidney, heart and brain.

Blood pressure should be gradually lowered since cerebral hypo perfusion can occur if the blood pressure is lowered by more than 40% in the initial 24 hours 

Drugs used to treat hypertensive emergencies in Uganda include intravenous hydralazine or Labetalol 

Hypertensive urgency 

This is a situation in which blood pressure is very elevated but there is no potential organ damage 

The blood pressure must be reduced within 1 – 2 days and oral medications are recommended used for example Nifedipine (Sublingual), Captopril, Labetalol tablet e.t.c.

Drugs used in the treatment of hypertension 

Drugs used in the treatment of hypertension in Uganda include: 

  • Beta blockers 
  • Calcium channel blockers
  • Diuretics 
  • Angiotensin converting enzyme inhibitor(ACE inhibitors)
  • Angiotensin II antagonist  
  • Centrally acting hypertensive
  • Direct  acting  vasodilators 


1. Beta blockers 

Beta blockers are the most commonly used drugs in the treatment of hypertension in Uganda because they are affordable and available in most of the places countrywide.



Atenolol (Totamol)



Mechanism of action

Beta blockers block beta 1 receptors in the heart which results in slowing of the heart rate and reduction in the force of heart contraction. This action results in lowering of blood pressure. 


  • Hypertension 
  • Angina pectoris 
  • Migraine headache 
  • Congestive heart failure (Carvedilol)
  • Post myocardial infarction 

Side effects 

  • Impotence 
  • Wheezing
  • Cold extremities 
  • Bradycardia 
  • Reduced exercise  tolerance 
  • Tiredness 
  • Heart  failure 


  • Patients with asthma 
  • Patients with acute heart failure
  •  Heart block 
  • Chronic obstructive airway disease
  • Patients with diabetes mellitus since they mask signs of hypoglycemia 
  • Depression 

Pregnancy and breast feeding 

  • Generally common beta blockers are recommended for use in pregnant mothers though prolonged use may lead to growth retardation in fetuses
  • Beta blockers may be used in breast feeding mothers 

2. Calcium channel blockers 

Calcium channel blockers are among the first line drugs used in the treatment of hypertension. They can be used alone or in combination with other antihypertensive such as beta blockers, Angiotensin converting enzyme inhibitors or diuretics .These drugs can be used safely in patients who also have other co existing conditions such as asthma, hyperlipidaemia, diabetes mellitus and renal dysfunction.





Mechanism of Action.

Calcium channel blockers decrease the entry of calcium ions into the smooth muscles causing vasodilatation and lowering of the blood pressure.


  • Hypertension 
  • Angina pectoris 

Side effects 

  • Flushing 
  • Oedema 
  • Headache 
  • Postural hypotension 
  • Dizziness 
  • Weakness 
  • Heart burn
  • Tachycardia 


  • 2nd or 3rd degree heart block
  • Known hypersensitivity to any of the members 
  • Severer heart failure  
  • Severe hypotension 

Pregnancy and breast feeding 

Calcium channel blockers especially Nifedipine is used in the treatment of hypertension in pregnant mothers 

3.  Diuretics 

Diuretics are among the first line drugs used in the treatment of hypertension. 

Diuretics for example Bendrofluazide are safe, cheap and effective in the treatment of hypertension. These drugs may be used alone or in combination with ACE inhibitors, beta blockers etc in the treatment of hypertension 

Classification of diuretics 



Thiazide diuretics 

Bendrofluazide (Aprinox)


Loop diuretics 

Frusemide (Lasix)

Potassium sparing diuretics 


Mechanism of action

Diuretics work by promoting the excretion of large amount of water in form of urine thereby reducing the blood volume and lowering of blood pressure. 


  • Hypertension 
  • Heart failure 

Note: Thiazide diuretics are mainly used in the treatment of hypertension but may be used in mild cases of heart failure 

Loop diuretics are commonly used in the treatment of heart failure and rarely in the treatment of hypertension unless associated with fluid over load (oedema)

Side effects


Common side effects 

Thiazide diuretics  

  • Hypokalaemia
  • Hyperuricaemia(elevated level of uric acid)
  • Glucose intolerance 
  • Sexual dysfunction(impotence)
  • Weakness 
  • Dehydration 

Loop diuretics 

  • Dehydration 
  • Dry mouth 
  • Muscle aches 
  • Hypokalaemia 
  • Elevation of blood sugar 
  • Postural hypotension 


Thiazide diuretics are not recommended in patients with

  • Gout
  • Diabetes
  • Hypokalaemia
  • Hyperlipidaemia
  • known hypersensitivity

 Pregnancy and breast feeding 

Generally diuretics should be used with caution during pregnancy and breast feeding  

4.  Angiotensin converting enzyme inhibitors (ACE inhibitors)

ACE inhibitors are drugs of first choice in the treatment of hypertension and also hypertension in diabetic patients. They may be used alone or in combination with diuretics or beta blockers. 






Mechanism of action

These drugs interfere with the conversion of Angiotensin I(vasodilator) to Angiotensin II           (vaso constrictor) by inhibiting the Angiotensin converting  enzyme. This leads to a reduction of peripheral resistance and lowering of blood pressure 


  • Hypertension 
  • Heart failure  
  • Diabetic nephropathy 

Side effects 

The common side effects associated with use of ACE inhibitors include 

  • Dry irritating cough 
  • Skin rash
  • Taste disturbance 
  • Angioedema 


  • Pregnant mothers 
  • Patients with renal impairment 
  • Previous history of angioedema 
  • Known hypersensitivity to any of the drugs in this group
  • Breast feeding 

5. Centrally acting antihypertensive 

These drugs were among the first to be used in the treatment of hypertension in Uganda. They are no longer used so much in the general management of hypertension because of associated side effects and presence of effective drugs with less side effects.


  • Methyldopa 
  • Clonidine 

Methyldopa, the only member currently registered in Uganda is used as a drug of 1st choice in the treatment of hypertension in pregnant mother because of its safety in this category of patients 

Mechanism of action

These drugs inhibit sympathetic out flow from the brain there by decreasing total peripheral resistance and lowering of blood pressure.


  • Hypertension during pregnancy 
  • Severe hypertension as a 3rd line drug 

Side effects 

  • Tiredness 
  • Headache 
  • Impotence 
  • Dizziness 
  • Mental depression 
  • Sedation 
  • Rebound hypertension on withdraw 


  • Severe liver disease 
  • Known hypersensitivity to methyldopa

6. Angiotensin II antagonists 

These drugs are among the new ones used in the treatment of hypertension .They are as effective as ACE inhibitors but are usually recommended in patients who cannot tolerate ACE inhibitors because of side effects such as cough.






Mechanism of action 

Angiotensin II antagonists bind tightly at Angiotensin II receptor preventing the action the action of Angiotensin II .This action reduces peripheral resistance resulting into vasodilatation and lowering of blood pressure 


  • Hypertension 
  • Heart failure 

Side effects 

The most common side effects associated with the use of these drugs include:

  • Hypotension 
  • Dizziness
  • Hyperkalaemia 


These drugs should be avoided during pregnancy especially during the 2nd and 3rd trimester since they are associated with fetal malformation 

  • Breast feeding mothers 

7.  Direct acting vasodilators 

Drugs that belong to this group include 

  • Hydralazine 
  • Minoxidil

Hydralazine is the only member registered in Uganda and is only recommended in the treatment of hypertension that has not responded to other antihypertensive.

The use of hydralazine in the long term treatment of hypertension is associated with fluid retention and reflex tachycardia which can be offset by combining it with beta blockers (to prevent reflex tachycardia or diuretics to reduce fluid retention) 

Mechanism of action

Direct acting vasodilators work directly on the blood vessels causing relaxation (widening of the blood vessel) leading to a reduction in the blood pressure 


  • Severe hypertension 
  • Hypertensive emergences 
  • Hypertension in pregnancy associated with pre- eclampsia and eclampsia 

Side effects 

The following side effects are commonly seen when hydralazine is used 

  • Headache 
  • Tachycardia 
  • Flushing 
  • Dyspnoea 
  • Oedema 
  • Postural hypotension 


  • Angina pectoris 
  • Patients with heart failure  
  • Known hypersensitivity
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