Antihypoglycaemic (KATP channel opener) Pregnancy: Avoid — fetal hyperglycaemia, maternal hyperuricaemia, uterine relaxation. Insulinoma in pregnancy: specialist multidisciplinary management (somatostatin analogues, surgery).

Diazoxide

Brand names: Eudemine, Proglycem

Adult dose

Dose: Chronic hypoglycaemia from insulinoma: 5 mg/kg/day in 2–3 divided doses, max 1000 mg/day; titrate to symptom and BG control.

Route: Oral

Frequency: BD–TDS

Max: 1000 mg/day

Co-prescribe a thiazide diuretic (e.g., bendroflumethiazide 5 mg OD, or chlorthalidone) to counter fluid retention and potentiate hyperglycaemic effect. IV preparation no longer used for hypertensive emergencies in the UK — labetalol or hydralazine preferred.

Paediatric dose

Dose: 5 mg/kg

Route: Oral

Frequency: BD–TDS

Max: 20 mg/kg/day in neonatal hyperinsulinaemic hypoglycaemia

Neonatal congenital hyperinsulinism: start 5 mg/kg/day in 3 divided doses; titrate to 15–20 mg/kg/day if needed. Always co-prescribe a thiazide. Specialist endocrine supervision essential.

Dose adjustments

Renal

Caution; reduce dose.

Hepatic

Caution; reduce dose.

Paediatric weight-based calculator

Patient weight (kg)

Neonatal congenital hyperinsulinism: start 5 mg/kg/day in 3 divided doses; titrate to 15–20 mg/kg/day if needed. Always co-prescribe a thiazide. Specialist endocrine supervision essential.

Clinical pearls

Mechanism: opens pancreatic β-cell KATP channels → suppresses insulin secretion → reverses hypoglycaemia. Effective in benign insulinoma, congenital hyperinsulinism, and post-bariatric surgery hypoglycaemia.
Always combine with a thiazide diuretic to (a) reduce fluid retention and (b) potentiate glycaemic effect — a forgotten thiazide is a common cause of treatment failure.
Hypertrichosis is the most distressing chronic side effect — counsel before starting; offer cosmetic hair-removal advice.
Neonatal hyperinsulinism: pulmonary hypertension is a recognised complication (FDA box warning) — cardiac echocardiography before and during treatment in neonates.
IV diazoxide is no longer used for hypertensive emergencies (overshoot hypotension and reflex tachycardia) — replaced by labetalol, hydralazine, or sodium nitroprusside.

Contraindications

Hypersensitivity to thiazides, sulfonamides, or diazoxide
Eclampsia / pre-eclampsia (causes uterine relaxation, fetal compromise)
Pulmonary hypertension (rebound severe pulmonary HTN reported in neonates)
Aortic coarctation, AV shunts (acute hypotensive collapse with IV)

Side effects

Hypertrichosis (very common in chronic use — fine soft hair growth, often distressing for women/girls; reversible 6 months after stopping)
Sodium and water retention, oedema, weight gain (counter with thiazide)
Hyperglycaemia (intended therapeutic effect — but overshoot causes diabetic ketoacidosis or HHS)
Hyperuricaemia, gout
Pulmonary hypertension in neonates (BLACK-BOX warning FDA; cases reported with cardiac shunts)
Thrombocytopenia, leucopenia
Hypotension on initiation (especially IV historically)
GI upset

Interactions

Thiazide diuretics: synergistic — co-prescribed therapeutically
Antidiabetic agents (insulin, sulphonylureas): antagonised — adjust as glycaemic effect develops
Phenytoin: ↓ phenytoin levels via diazoxide induction
Anticoagulants: ↑ effect (protein-binding displacement)
Antihypertensives: additive hypotension

Monitoring

Blood glucose 2–4 hourly initially then daily–weekly
U&Es, urate
FBC monthly
Echocardiogram (neonates and children)
Weight, oedema

Reference: BNFc; BNF 90; BNF for Children 2024; SmPC Eudemine; FDA Drug Safety Communication July 2015 (pulmonary HTN); BSPED Hyperinsulinism Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Pathways