Bendroflumethiazide
Thiazide and thiazide-like diuretics
Thiazide and thiazide-like diuretics
A thiazide diuretic tablet, usually taken in the morning. It treats high blood pressure and fluid build-up (oedema).
Also called: Bendrofluazide
Quick facts
- Group
- Thiazide and thiazide-like diuretics
- Target
- Sodium-chloride cotransporter (NCC) of the distal convoluted tubule
- Used for
- High blood pressure · Oedema
- Key effects
- Increased urination · Nausea · Joint pain and gout
- Monitor
- Sodium · Kidney function · Blood glucose and uric acid
- ATC
- C03AA01
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows hydrochlorothiazide, a closely related thiazide, in the binding site of the human sodium-chloride cotransporter; bendroflumethiazide occupies the same site.
Bendroflumethiazide blocks the sodium-chloride cotransporter in the distal convoluted tubule, so more sodium, chloride and water are excreted. Blood volume falls at first; with continued use, peripheral resistance falls and lowers blood pressure. More sodium reaching the collecting duct increases potassium loss, and calcium reabsorption increases.
- It blocks NCC in the distal convoluted tubule
- More sodium, chloride and water are excreted
- Volume and then vascular resistance fall
- Potassium is lost; calcium is retained
Indications
- High blood pressure Arterial hypertension →
- Oedema (fluid build-up), for example in heart failure Heart failure →
Adverse effects
Common
- Increased urination, thirst and dry mouth
- Dizziness or fainting from low blood pressure
- Nausea, vomiting, diarrhoea, constipation or reduced appetite
- Joint pain and gout
Contraindications
- Addison's disease
- Low sodium, potassium or magnesium, or high calcium
- Symptomatic high uric acid or gout
- Kidney or liver problems (used with caution or avoided)
- Caution: diabetes, lupus
Key interactions
- Digoxin and drugs for heart rhythm (amiodarone, sotalol, flecainide)
- Low potassium from the thiazide raises the risk of toxicity and arrhythmias
- NSAIDs
- Weaker blood pressure effect and more risk to the kidneys
- Insulin and other diabetes medicines
- Glucose control may worsen
- Calcium or vitamin D supplements, calcitriol
- Risk of high calcium
What is monitored
- Sodium, potassium, magnesium and calcium
- Kidney function
- Blood glucose and uric acid
- Blood pressure
Administration and safety
- Taken in the morning so that urination does not disturb sleep; a second dose, if any, around midday
- Tablets are swallowed whole with water
- Soluble medicines high in sodium can weaken the blood pressure effect
Pregnancy and breastfeeding
It is not normally used in pregnancy, as other medicines are preferred for high blood pressure. In breastfeeding only low levels reach milk, but long-term use might reduce milk supply.
Nursing care
- Check electrolytes and kidney function results
- Ask about dizziness on standing and advise rising slowly
- Teach the signs of dehydration and low potassium (weakness, cramps)
- Ask about gout attacks and check glucose in diabetes
Pharmacokinetics
- Absorption
- Taken by mouth, with or without food
- Onset and duration
- Increased urination within hours, so it is taken in the morning
Test yourself
Think of the answer, then tap the question to see it.
Which transporter does bendroflumethiazide block, and where?
The sodium-chloride cotransporter (NCC) in the distal convoluted tubule.
Why is bendroflumethiazide taken in the morning?
Its diuretic effect would otherwise wake the person at night to pass urine.
Which metabolic changes can thiazides such as bendroflumethiazide cause?
Low potassium, sodium and magnesium, high calcium, high uric acid (gout) and high glucose.
Why is low potassium dangerous for someone also taking digoxin?
Hypokalaemia increases digoxin toxicity and the risk of arrhythmias.
Connections
← Back to the class: Thiazide and thiazide-like diuretics
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Bendroflumethiazide: diuretic to treat high blood pressure and build-up of fluid - NHS (NHS (UK), 2026); Who can and cannot take bendroflumethiazide - NHS (NHS (UK), 2026); Side effects of bendroflumethiazide - NHS (NHS (UK), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.