Thiazide Diuretic Pregnancy: Avoid in pregnancy; may suppress neonatal lactation

Bendroflumethiazide

Brand names: Aprinox

Adult dose

Dose: 2.5 mg once daily

Route: Oral

Frequency: Once daily (morning)

Max: 2.5 mg/day for hypertension (higher doses not more effective, increase ADRs)

Largely superseded by thiazide-like diuretics (indapamide, chlortalidone) with better cardiovascular outcome data

Paediatric dose

Dose: Seek specialist opinion N/A/kg

Route: Oral

Frequency: Seek specialist opinion

Max: Seek specialist opinion

Seek specialist opinion

Dose adjustments

Renal

Avoid if eGFR under 30 — ineffective and risk of electrolyte disturbances

Hepatic

Risk of hypokalaemia-induced encephalopathy in hepatic impairment

Paediatric weight-based calculator

Patient weight (kg)

Seek specialist opinion

Clinical pearls

NICE NG136: thiazide-like diuretics (indapamide 1.5 mg MR) preferred over bendroflumethiazide due to superior cardiovascular outcome data from ALLHAT and ASCOT
Hyponatraemia is the most dangerous electrolyte complication in elderly — risk increased with SSRIs, hot weather, poor fluid intake
Gout: thiazides raise uric acid — review if patient develops acute gout on treatment
STOPP criteria: avoid thiazides in patients with gout (contraindicated) or established hyponatraemia
Morning dosing prevents nocturia — particularly important in elderly to reduce falls risk

Contraindications

Addison disease
Hypercalcaemia
Hyponatraemia
Refractory hypokalaemia
Sulfonamide allergy (cross-reactivity possible)

Side effects

Hypokalaemia
Hyponatraemia (elderly particularly vulnerable)
Hyperuricaemia / gout
Impaired glucose tolerance / new-onset diabetes
Postural hypotension
Erectile dysfunction

Interactions

NSAIDs (reduce diuretic effect, increase AKI risk)
Digoxin (hypokalaemia increases toxicity)
Lithium (thiazides increase lithium levels)
ACE inhibitors / ARBs (enhanced antihypertensive effect — synergistic)

Monitoring

U&E (Na, K, creatinine) at baseline, 1 month, then annually
Uric acid if gout risk
Blood glucose
Blood pressure

Reference: BNFc; BNF 90; NICE NG136 (Hypertension); ALLHAT Trial; STOPP/START v3. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

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