Ridaq Side Effects

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

What is Ridaq?

Ridaq contains the active ingredient Hydrochlorothiazide.

• Active ingredient — Hydrochlorothiazide
• Registration number — 60/18.1/0846
• Registration holder — Gulf Drug Company (Pty) Ltd

It is approved for:

• Swelling due to retained fluid (oedema) due to salt and water retention, or due to serious heart, liver or kidney problems
• Diabetes insipidus (a condition which causes abnormally large amounts of urine to be passed and increased thirst) where Thiaretic may be of value in managing this disease due to it having the opposite effect of retaining fluids in the body (antidiuretic effect) in these patients
• High blood pressure that has an unknown cause (essential hypertension), in combination with or without other specific medicines used to treat high blood pressure

Common side effects of Ridaq

Not everyone gets side effects. The effects below are those listed in the South African approved leaflet, grouped using the leaflet’s own frequency wording.

Frequent side effects

• Decreased appetite
• High blood sugar (hyperglycaemia) 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

Less frequent side effects

• Restlessness
• Mental and physical sluggishness (lethargy), drowsiness
• Headache, dizziness
• Burning or prickling sensation (pins and needles) that is usually felt in the hands, arms, legs, or feet (paraesthesia)
• Yellow and/or blurred vision
• A fall in blood pressure on standing up which causes dizziness or fainting (postural hypotension)
• Stomach and intestine complaints and irritation, dry mouth, nausea, vomiting, constipation, diarrhoea 19
• A sore or ulcer that develops on the lining of the food pipe (oesophagus), stomach or small intestine (intestinal ulceration) with symptoms such as pain in the upper part of the stomach
• Rash, itchy, raised, red or skin-coloured welts or hives on the skin’s surface (urticaria)
• Red, itchy patches on your skin when you have been outside (even on a cloudy day) due to skin’s overreaction to sunlight (photosensitivity reaction)
• Muscle pain and cramps, muscle spasm
• Loss of male sexual ability (impotence)
• Thirst, weakness and fever (high temperature). Side effects occurring with frequency unknown
• Infection of salivary glands (sialadenitis)
• Depression, a mood disorder that causes a persistent feeling of sadness or worthlessness and loss of interest
• Difficulty to sleep
• Feeling unsteady or giddy (vertigo)
• Stomach and intestinal cramps
• Hair loss or baldness (alopecia)

Serious side effects and warning signs

This leaflet does not set out a separate list of serious side effects. The general warning signs below apply to any medicine.

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

The approved leaflet identifies the following cautions and factors.

Do not use it at all if

• if you are hypersensitive (allergic) to hydrochlorothiazide, other medicines containing sulfonamides or any of the other ingredients of Thiaretic (listed in section 6)
• if you have severe kidney problems
• if you have severe liver problems
• if you have Addison’s disease when your adrenal glands, located just above your kidneys, does not produce enough steroid hormones – e.g. too little cortisol and, often, too little aldosterone)
• if you have too much calcium in your blood (hypercalcaemia)
• if you have previously had or currently have cancer of the skin and/or lip
• if you are in the second or third trimester of pregnancy
• if you are breastfeeding your baby 2
• if you are taking lithium, a medicine used to treat depression

Use with care, and tell your doctor, if

• if you have severe liver problems the small changes caused by Thiaretic in the amount of different salts in your body (electrolytes) in your blood, may cause the loss of brain function which can include forgetfulness, confusion and breath with a sweet or musty odour and can progress to shaking of the hands or arms, disorientation and slurred speech and loss of consciousness (coma). If you experience these symptoms, stop taking Thiaretic and contact your doctor immediately
• if you have kidney problems, you may show elevated levels of urea and other nitrogen compounds in the blood (azotaemia) and produce abnormally small amounts of urine than what is usual for you (oliguria) and your kidneys’ ability to remove waste and balance fluids in your body become progressively worse. Your doctor might discontinue the use of
• if you suffer from very high levels of uric acid in your blood, Thiaretic may trigger a gout attack which is characterised by severe pain, redness and tenderness in your joints
• if you have high blood sugar, Thiaretic 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 are experiencing symptoms of a disturbances of the amount of different salts in your body (electrolyte imbalances) such as a dry mouth, thirst, weakness, tiredness, drowsiness, restlessness, confusion, fits, muscle pains, cramps or weakness, low blood 3 pressure, passing a reduced amount of urine, a fast, irregular heartbeat, breathing problems or nausea and vomiting. If you are an elderly patient you may be more prone to 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 experience a sudden drop in blood pressure when standing up after sitting or lying down (orthostatic hypotension) which can make you feel lightheaded or dizzy when you stand, causing blurred eyesight, weakness and fainting
• if you experience symptoms of having too much calcium in your blood (hypercalcaemia) such as excessive thirst, frequent urination. upset stomach, nausea, vomiting, constipation. bone pain. muscle weakness, confusion, feeling very tired and having very fast heartbeats (palpitations) and other changes in the way your heart beats. You should contact your doctor if you develop these signs and symptoms that might indicate hypercalcemia
• if you develop a blood level that is below normal in potassium, an important body chemical (hypokalaemia). The problem can result in fatigue, muscle cramps and abnormal heart rhythms. You should contact your doctor
• if you develop symptoms of metabolic alkalosis, a condition where the pH of tissue is elevated beyond the normal range, such as confusion (this can progress to a state of state of near-unconsciousness or insensibility or complete unconsciousness), shaking of your hands, light-headedness, muscle twitching, nausea, vomiting, numbness or tingling in the face, hands, or feet and prolonged muscle spasms (tetany). You should contact your doctor
• if you develop symptoms of low sodium concentration in your blood (hyponatraemia) such as confusion, irritability, disorientation in mild cases to seizures (fits), brain swelling and coma in serious cases which can be life-threatening, you should contact your doctor 4
• if you experience symptoms related to low magnesium levels in your blood (hypomagnesaemia) such as shaking, muscle spasms, muscle cramps and/or numbness in your hands and feet, abnormal eye movements (nystagmus), fatigue and weakness, fits, confused thinking and a lack of awareness of your surroundings (delirium) and abnormal heart rhythms (dysrhythmia). You should contact your doctor if you experience any of these symptoms
• if you experience a decrease in vision or eye pain. These could be symptoms of fluid accumulation in the vascular layer of the eye (choroidal effusion) or an increase of pressure in your eye and can happen within hours to weeks of taking Thiaretic. This can lead to permanent vision loss, if not treated. If you earlier have had a penicillin or sulfonamide allergy, you can be at higher risk of developing this
• if you had skin cancer or if you develop an unexpected skin lesion during treatment with Thiaretic. Treatment with Thiaretic, particularly long-term use with high doses, may increase the risk of some types of skin and lip cancer (non-melanoma skin cancer). Protect you skin from sun exposure and UV rays while taking Thiaretic
• if you suffer from systemic lupus erythematosus (SLE), a chronic condition in which the immune system attacks its own tissues, causing widespread inflammation and tissue damage in the affected organs. It can affect the joints, skin, brain, lungs, kidneys, and blood vessels and can be life-threatening in severe cases. Thiaretic may activate or worsen this condition
• if you are taking blood pressure medicines (antihypertensives) used to bring your blood pressure down, as Thiaretic can make your blood pressure drop too low and cause you to experience confusion, dizziness, nausea, fainting (syncope), fatigue, neck or back pain, headache, blurred vision, heart palpitations, or feelings that your heart is skipping a beat, fluttering, or beating too hard or too fast 5
• if you suffer from high cholesterol and high triglyceride (types of fat in your blood) levels as Thiaretic may increase these levels
• if you have a history of allergy or asthma as Thiaretic may cause allergic reactions
• if you develop an inflammation of the organ lying behind the lower part of the stomach (pancreas) causing severe upper belly pain that may spread to your back or chest (it may feel worse after you eat), nausea and vomiting
• if you are taking lithium to treat a mental disorder, since the combination with Thiaretic may lead to toxic blood concentrations of lithium which can include feeling weak, having a worsening tremor, feeling unbalanced or uncoordinated, poor concentration, diarrhoea, severe nausea, vomiting, slurred speech and confusion
• if you had a surgery to stop excessive sweating called a sympathectomy as Thiaretic can then make your blood pressure drop too low
• if you are going to have an anti-doping test, Thiaretic could show a false positive result

Pregnancy and breastfeeding

• You should not take Thiaretic while you are pregnant or breastfeeding your baby
• If you are pregnant or breastfeeding, think you may be pregnant or are planning to have a baby, please consult your doctor, pharmacist or other health care provider for advice before taking this medicine

Interactions and medicines to check

The approved leaflet names these interactions.

• Thiaretic can interact with the following medicines to make their effect and risk of adverse effects stronger. If you are taking any of the following, your doctor might monitor you more closely: o Calcium salts used to treat calcium deficiency as there can be an increase in your calcium blood levels o Medicines to treat problems with the way the heart beats such as digoxin as this can cause too low potassium levels in your blood, your doctor might change your treatment o Skeletal muscle relaxants (e.g., tubocurarine) used to produce muscle relaxation and often used during surgery 6 o Antihypertensive medicines (e.g. enalapril, perindopril), used to treat high blood pressure o Lithium used to treat mental disorders o Anti-dysrhythmic medicines (amiodarone, sotalol, adenosine, verapamil, flecainide acetate) used to treat heart rhythm disorders. This can cause a specific type of abnormal heart rhythm that can lead to sudden cardiac death (Torsades de Pointes) o Antipsychotics (e.g., flupentixol, fluphenazine, haloperidol) which are medicines used to treat mental disorders such as an inability to think, feel and behave clearly (schizophrenia) and a disconnection from reality (psychosis). o Metformin (used to help lower blood sugar levels in people with type 2 diabetes) – you may have an increased risk of lactic acid building up in your blood (lactic acidosis) causing symptoms like confusion and fatigue and possible kidney problems o Medicines used to treat gout (such as probenecid, allopurinol). You may experience hypersensitivity reactions such as itching and rash o Amantadine (medicine for Parkinson’s disease also used to treat or prevent certain illnesses caused by viruses) o Medicines that stops the growth of cells, including cancer cells (cytostatics) used in the treatment of cancer (cyclophosphamide) or to treat rheumatoid arthritis, juvenile idiopathic arthritis, vasculitis and psoriatic arthritis (methotrexate) o Quinidine (used to manage and treat certain types of irregular heartbeats and malaria in patients)
• Thiaretic can interact with the following medicines to make their effect weaker: o Antidiabetic medicines (insulin and oral antidiabetics) used to treat high sugar in the blood caused by diabetes mellitus. Thiaretic can increase blood sugar levels and 7 interfere with diabetic control
• You may need a dose adjustment or more frequent monitoring of your blood sugar to safely use both medicines o Noradrenaline (norepinephrine) and adrenalin (epinephrine) used to treat low blood pressure in specific situations and serious allergic reactions
• Some medicines can interact with Thiaretic to make its effect and risk of adverse effects stronger. If you are taking the medicines below, your doctor might monitor you more closely. o The following medicines can interact with Thiaretic and decrease levels of potassium in your blood below acceptable levels (hypokalaemia) which can cause attacks of severe muscle weakness, eventually leading to paralysis and possibly respiratory failure (when your lungs cannot get enough oxygen into your blood or remove enough carbon dioxide):
• Some water tablets (e.g., furosemide)
• ACTH or corticotropin used to test if you have problems with your adrenal gland e.g., when you have Addison’s disease or to treat multiple sclerosis in adults and spasms in children
• Amphotericin B (injection) used to treat fungal infections
• Beta2-agonists (e.g., salbutamol, albuterol) used to treat asthma
• Carbenoxolone used to treat stomach ulcers
• Corticosteroids (e.g., prednisone, methylprednisone) used as anti-inflammatory medicine and to prevent an immune response
• Stimulant laxatives (e.g., bisacodyl, senna) used to treat constipation
• Penicillin G sodium, an injectable antibiotic
• Salicylic acid and derivatives (e.g. aspirin) used to treat pain, fever and inflammation. 8 o The following medicines can interact with Thiaretic and increase the side effect of postural hypotension which is low blood pressure that happens when standing after sitting or lying down causing dizziness and possibly fainting:
• Alcohol
• Barbiturates (e.g., phenobarbital) which are used to calm you or induce sleep (sedatives)
• Opioids (e.g., morphine, oxycodone, tramadol, codeine) used to treat pain
• Phenothiazines (e.g. chlorpromazine and promethazine) used to treat serious mental and emotional disorders, including schizophrenia and other psychotic disorders
• Tricyclic antidepressants (e.g. amitriptyline, clomipramine, nortriptyline, imipramine) used to treat depression as well as manage a variety of other conditions. o Baclofen (a skeletal muscle relaxant used for treatment of multiple sclerosis or certain injuries to the spine) can strengthen the blood pressure lowering effect of Thiaretic. Your doctor may monitor your blood pressure and renal function and may adapt your dosage of the Thiaretic o The following medicines can interact with Thiaretic and decrease levels of sodium in your blood below acceptable levels (hyponatraemia) which can cause you to experience nausea and vomiting, confusion, seizures, or lost consciousness:
• Carbamazepine used to treat recurrent fits (epilepsy)
• Selective serotonin reuptake inhibitors (SSRIs) (for example citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, vortioxetine) used to treat depression. 9 o Anti-cholinergic medicines (medicines used to treat a variety of disorders such as gastrointestinal cramps, urinary bladder spasm, asthma, motion sickness, muscular spasms, Parkinson’s disease and as an aid to anaesthesia) such as atropine and biperiden o The following medicines can interact with Thiaretic and increase levels of uric acid in your blood which can lead to health problems such as gout and kidney stones:
• Tetracyclines (antibiotic) used to treat a number of infections
• Ciclosporin (medicine which is used in the case of organ transplants) o Vitamin D – you may experience increased levels of calcium in your blood o Diazoxides (medicines used to treat hypoglycaemia) and beta blockers (used to manage abnormal heart rhythms, to treat heart cramps/chest pain and reduce high blood pressure). You may experience excessive increase in blood sugar levels o Methyldopa (used in the management and treatment of high blood pressure) – you may develop a disorder in which red blood cells are destroyed faster than they can be made (haemolytic anaemia)
• Some medicines can interact with Thiaretic to make its effect weaker: o Non-steroidal anti-inflammatory drugs (NSAIDs) (e.g., indometacin, ibuprofen), including COX-2 inhibitors (e.g., celecoxib, etoricoxib) used to treat pain, fever, inflammation and blood clots (e.g., aspirin) o Colestyramine resin and colestipol used to treat high cholesterol (a type of fat in your body that helps your body perform many important jobs)
• Thiaretic can change the results of some laboratory tests: 10 o Laboratory tests for parathyroid function: Blood or urinary tests to test the function of the parathyroid glands (four small glands that lie behind the thyroid in the neck and produce parathyroid hormone, which plays a role in regulating the body’s blood level of calcium and phosphorus) o Laboratory tests for pancreas function: Blood or urinary tests to test the function of the pancreas (an organ located in the abdomen that plays an essential role in converting the food we eat into fuel for the body’s cells by helping in digestion and regulating blood sugar) o Laboratory tests for thyroid function. Thiaretic with food, drink and alcohol The tablets should be swallowed with a glass of water and should be taken with or after meals to minimise stomach upset. Do not take Thiaretic with alcohol as you can have an increased risk of dizziness and possibly fainting

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.

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