Blood pressure medication Side Effects

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Answer the side-effect intent for blood pressure medication without diagnosing; distinguish common from serious reactions and give safe next-step/reporting guidance.

Part of cardiovascular side effects.

What is blood pressure medication?

Blood pressure medicines covers several products registered in South Africa, not one. They work in a similar way, and their approved leaflets do not list identical side effects.

The medicines covered here, and the leaflet used for each:

• amlodipine — ASCIVASC, Ascendis Pharma (Pty) Ltd (Tablets)
• enalapril — NATRAPRESS, Smart Pharmaceuticals (Pty) Ltd (Tablets.)
• hydrochlorothiazide — RIDAFLO 12,5; 25 & 50, Austell Pharmaceuticals (Pty) Ltd (Tablet)
• losartan — AMIZART, Smart Pharmaceuticals (Pty) Ltd (Film-coated Tablets)
• perindopril — Prexum, Servier Laboratories SA (Pty) Ltd (Film-coated tablet.)

Common side effects of blood pressure medication

Each medicine in this group has its own approved leaflet, and the effects below are the ones that leaflet lists. They are shown separately rather than combined, because the leaflets do not agree on what to list or how to word it.

Amlodipine (ASCIVASC)

• water retention (causing swelling of your ankles, hands and feet)
• headache, dizziness, sleepiness (especially at the beginning of treatment)
• pain in your stomach area, feeling sick (nausea), feeling bloated (caused by excessive gas)
• changes in bowel movements, such as constipation or diarrhoea
• visual disturbances, double vision
• muscle cramps, physical weakness and lack of energy
• flushing of your skin (blushing)
• bleeding or small pin-sized purple spots on the skin
• feeling depressed or confused, mood changes, anxiousness, and insomnia
• shaking (tremor)
• distortion of the sense of taste; Date amended: 06 August 2023 (Response to PV letter –
• numbness, a loss of sensation, tingling or numbness in your hands or feet, feeling of weakness or heaviness in your arms and legs

The leaflet lists 16 more. Read the full leaflet.

Enalapril (NATRAPRESS)

• light-headedness due to low blood pressure
• headache, mood alterations, depression
• blurred vision
• heart attack or stroke, rapid forceful heartbeat, chest pain, angina
• dizziness, fainting
• cough, difficult breathing
• nausea, diarrhoea, abdominal pain, changes in taste
• rash, swelling of the face, lips, tongue or throat
• weakness, tiredness
• generally feeling unwell (malaise), high temperature (fever)
• high levels of potassium in the blood, increased levels of creatinine in your blood (both are usually detected by a test)
• changes in blood values such as a lower number of white and red blood cells, lower haemoglobin, lower number of blood platelets

The leaflet lists 27 more. Read the full leaflet.

Hydrochlorothiazide (RIDAFLO 12,5; 25 & 50)

• electrolyte imbalances, decrease in chloride in the blood, low blood levels of sodium which can cause tiredness and confusion, muscle twitching, fits and coma (may occur in patients with severe heart failure who have swelling due to retained fluid, especially with large doses of RIDAFLO in conjunction with restricted salt in the diet)
• stomach and intestine complaints, dry mouth
• thirst, weakness
• mental and physical sluggishness, drowsiness
• restlessness
• muscle pain and cramps
• reduced urine production
• metabolic (physical and chemical processes necessary to maintain life) disturbances especially at high doses
• high blood sugar and the presence of glucose in the urine (glycosuria) in diabetic and other susceptible patients
• increased levels of uric acid in the blood that causes attacks of gout in some patients
• the urinary excretion of calcium is reduce
• deficiency of magnesium in the blood

The leaflet lists 23 more. Read the full leaflet.

Losartan (AMIZART)

• dizziness
• low blood pressure (especially after excessive loss of water from the body within blood vessels e.g. in patients with severe heart failure or under treatment with high dose diuretics)
• dose-related orthostatic effects such as lowering of blood pressure appearing when rising from a lying or sitting position
• debility (feeling weak and loss of energy)
• fatigue
• too little sugar in the blood (hypoglycaemia)
• too much potassium in the blood (hyperkalaemia)
• changes in kidney function including kidney failure
• reduced number of red blood cells (anaemia)
• increase in blood urea, serum creatinine and serum potassium in patients with heart failure
• somnolence
• headache

The leaflet lists 38 more. Read the full leaflet.

Perindopril (Prexum)

• headache
• dizziness
• vertigo
• pins and needles
• vision disturbances
• tinnitus (sensation of noises in the ears)
• cough
• shortness of breath (dyspnoea)
• gastro-intestinal disorders (nausea, vomiting, abdominal pain, taste disturbances, dyspepsia or difficulty of digestion, diarrhoea, constipation)
• allergic reactions (such as skin rashes, itching)
• muscle cramps
• feeling of tiredness

The leaflet lists 36 more. Read the full leaflet.

Serious side effects and warning signs

None of the leaflets reviewed set out a separate serious-effects list.

General warning signs that apply to any medicine

How long can side effects last?

How long a side effect lasts depends on the effect, the product, how long it has been used, and the person. Some effects ease within days as the body adjusts. Others continue for as long as the product is used. A few can persist after stopping, and some need review rather than waiting.

• Settling effects — mild effects that ease over the first days or weeks of use
• Ongoing effects — effects that continue while the product is being used and improve after stopping
• Persistent effects — effects that continue after stopping and need medical review
• Delayed effects — effects that appear after weeks or months rather than immediately

Which of these applies to a particular effect is a clinical question. If a side effect is not settling, is getting worse, or is affecting your daily life, that is worth a conversation with a pharmacist or doctor regardless of how long it has been going on.

Factors that may affect side effects

Cautions from each medicine’s approved leaflet.

Amlodipine (ASCIVASC)

Do not use it at all if:

• If you are hypersensitive (allergic) to amlodipine, other calcium channel blockers or any of the other ingredients of ASCIVASC (listed in section 6)
• If you have severe low blood pressure
• If you have had shock or cardiogenic shock (a condition where your heart is unable to supply enough blood to the body)
• If you have aortic stenosis (narrowing of the heart valve of the aorta)
• If you recently (within the past 28 days) suffered a heart attack
• If you have unstable angina (chest pain which may occur when you are resting)

Use with care, and tell your doctor, if:

• If you have severe liver problems. Your doctor may need to monitor your liver function and adjust your dose of ASCIVASC accordingly
• If you suffer from heart failure
• If you are 65 years or older
• If you suffer from severe kidney problems
• If you suffer from diabetes
• If you have porphyria (a group of disorders that result in a buildup of natural chemicals called porphyrins in your body)

Enalapril (NATRAPRESS)

Do not use it at all if:

• if you are allergic to the active ingredient enalapril maleate or similar medicines (i.e. ACE inhibitors), or to any of the other ingredients in the tablet
• if you have a history of angioedema (symptoms such as itching, nettle-rash, wheezing or swelling of the hands, throat, mouth or eyelids) related to previous ACE inhibitor therapy
• if you have suffered from hereditary or angioedema of unknown cause
• if you have a condition called aortic stenosis (the narrowing of the exit of the left ventricle of the heart)
• if you suffer from hypertrophic cardiomyopathy (a heart disorder in which the walls of the ventricles (lower heart chambers) thicken (hypertrophy) and become stiff and the thickened muscle blocks the flow of blood out of the heart) or outflow obstruction
• if you have severe kidney disease

Use with care, and tell your doctor, if:

• if you have a heart problem
• if you have a condition involving the blood vessels in the brain
• if you have low blood pressure (you may notice this as faintness or dizziness, especially when standing)
• if you have kidney problems, are a dialysis patient, are taking diuretics (water tablets)
• if you have ever had an allergic reaction with swelling of the face, lips, tongue or throat with difficulty in swallowing or breathing. You should be aware that black patients are at increased risk of these types of reactions to ACE inhibitors, including NATRAPRESS
• if you are taking an mTOR inhibitor (e.g. temsirolimus, sirolimus, everolimus: medicines used to treat certain types of cancer or to prevent the body’s immune system from rejecting a transplanted organ). You may be at increased risk for an allergic reaction called angioedema

Hydrochlorothiazide (RIDAFLO 12,5; 25 & 50)

Do not use it at all if:

• if you are hypersensitive (allergic) to hydrochlorothiazide, other medicines containing sulphonamides or any of the other ingredients of RIDAFLO (listed in section 6)
• if you have severe kidney problems
• if you have severe liver problems
• if suffer from Addison’s disease (when your adrenal glands, located just above your kidneys, produce too little cortisol and, often, too a little aldosterone)
• if you have too much calcium in your blood (hypercalcaemia)
• if you are in the second or third trimester of pregnancy

Use with care, and tell your doctor, if:

• if you have liver problems
• if you have high blood sugar. RIDAFLO may cause increased blood sugar and aggravate or unmask diabetes mellitus (a disease that results in too much sugar in the blood with symptoms such as severe thirst, frequent urination, tiredness, weight loss and blurred vision). Your blood sugar concentrations should be monitored if you are taking any medicine to treat diabetes
• if you suffer from high cholesterol and high triglyceride (a type of fat in your blood) levels, RIDAFLO may increase these levels
• if you have kidney problems
• if you suffer from gout characterized by severe pain, redness and tenderness in joints, RIDAFLO may cause an attack of this condition
• if you are experiencing a dry mouth, thirst, weakness, tiredness, drowsiness, restlessness, confusion, fits, muscle pains, cramps or weakness, low blood pressure, passing a reduced amount of urine, a fast, irregular heartbeat, breathing problems or nausea and vomiting as these may be signs of disturbances of the amount of different salts in your body (electrolyte imbalances). You should be carefully observed for signs of fluid and electrolyte imbalance, especially if you are vomiting or receiving parenteral fluid (intravenous) therapy. If you are an elderly patient you may be more prone to electrolyte imbalances

Losartan (AMIZART)

Do not use it at all if:

• if you are allergic to losartan, or to any of the other ingredients of this medicine (listed in section 6)
• if you have developed swelling of the face, lips, mouth, tongue or throat and giant wheals on your skin when previously taking medicines called angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) – you should never take these medicines again
• if your doctor has told you that the thickness of your heart muscle is abnormally increased (hypertrophic obstructive cardiomyopathy (HOCM))
• if you suffer from obstruction of blood vessels to your heart or kidneys
• if you have severe kidney function problems
• if you are currently taking potassium sparing diuretics (“water tablets”) containing spironolactone, triamterene or amiloride

Use with care, and tell your doctor, if:

• if you have had a history of angioedema (swelling of the face, lips, throat, and/or tongue)
• if you suffer from excessive vomiting or diarrhoea leading to an extreme loss of fluid and/or if you receive diuretics (medicines that increase the amount of water that you pass out through your kidneys) or are under dietary salt restriction leading to an extreme loss of fluid and salt in your body
• if you are known to have narrowing or blockage of the blood vessels leading to your kidneys or if you have received a kidney transplant recently
• if your liver function is impaired
• if you suffer from heart failure with or without renal impairment or concomitant severe life- threatening cardiac arrhythmias. Special caution is necessary when you are treated with a ß-blocker concomitantly
• if you have problems with your heart valves or heart muscle

Perindopril (Prexum)

Do not use it at all if:

• you are allergic to perindopril, or to any other ACE-inhibitor or to any of the ingredients of Prexum (listed in Section 6)
• you are pregnant or trying to become pregnant
• you are breastfeeding or plan to breastfeed
• you have experienced symptoms such as wheezing, swelling of the face, tongue or throat, intense itching or severe skin rashes with previous ACE-inhibitor treatment or if you or a member of your family have had these symptoms in any other circumstances (This rare condition is known as angioedema)
• If you have porphyria
• if you have diabetes or impaired kidney function and you are treated with a blood pressure lowering medicine containing aliskiren

Use with care, and tell your doctor, if:

• If you are undergoing desensitisation treatment, or have had an allergic reaction during previous desensitisation treatment (e.g. treatments using bee, wasp or ant venom)
• are to undergo LDL apheresis (which is removal of cholesterol from your blood by a machine)
• If you are to undergo anaesthesia and/or surgery
• if you have recently suffered from diarrhoea or vomiting, or are dehydrated
• You have any other health problems, including: Kidney disease or if you are receiving dialysis. Liver disease. Diabetes. Heart disease
• Contact your doctor to re-evaluate your treatment if you are treated with ACE- inhibitors/Angiotensin receptor blockers together with a fluoroquinolone antibiotic

What to do if you experience side effects

If you think you are having a side effect, the response depends on how severe it is. Use the warning signs above first — if any of those apply, treat it as urgent.

If the symptom is severe or frightening

Get medical help immediately. Call 10177 for an ambulance, or 112 from a mobile phone, or go to the nearest emergency department. Take the product and its packaging with you if you can.

If the symptom is mild but bothering you

• Write down what the symptom is, when it started, and how it relates to when you take the product
• Check the leaflet that came with the product to see whether the symptom is listed
• Speak to your pharmacist — for many questions this is the fastest route to a useful answer
• Contact the prescriber if the symptom is affecting your daily life or is not settling

You can also report a suspected side effect in South Africa. Reporting does not replace getting medical advice, and you do not need to be certain the product was the cause.

When to seek urgent medical help

Some symptoms need medical attention straight away rather than an appointment in a few days. Do not wait to see whether they settle.

Get same-day medical advice if you have

• A high fever, or a rash together with feeling generally unwell
• Yellowing of the eyes or skin, or unusually dark urine
• Unusual bruising or bleeding that you cannot explain
• Severe or persistent vomiting or diarrhoea, especially if you cannot keep fluids down
• A sudden change in mood, or thoughts of harming yourself
• Any symptom that is rapidly getting worse

How to report a suspected side effect in South Africa

South Africa has an official system for reporting suspected side effects, run by the South African Health Products Regulatory Authority (SAHPRA). Reports from the public and from healthcare professionals are how safety signals get detected after a product is already in use.

Who can report

Anyone can report — you do not have to be a healthcare professional, and you do not need to prove that the product caused the problem. A suspicion is enough. Patients, caregivers and family members can all submit a report.

What to have ready

• The name of the product, its strength and form, and the batch number if you have it
• Why it was being used, and when it was started and stopped
• What the suspected reaction was, when it began, and how long it lasted
• Any other medicines, supplements or remedies being used at the same time
• Basic details about the person affected — age and sex are usually enough

How to report

SAHPRA accepts adverse reaction reports through its e-Services reporting system and through the Med Safety mobile app. Healthcare professionals can also report through the same routes. Current forms and access points are published on the SAHPRA site.

• SAHPRA Health Products Vigilance — the main vigilance and reporting hub
• SAHPRA e-Services — current adverse reaction reporting access

For a fuller walkthrough see how to report an adverse drug reaction.

Related pages

• Aspavor side effects

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