Endocrine & Metabolic/Sulfonylurea

Sulfonylureas

also: gliclazide · glimepiride · SU

Overview

Insulin secretagogues — effective and cheap, but cause hypoglycaemia and weight gain. Useful when rapid glucose control or symptoms.

Mechanism

Block the ATP-sensitive K⁺ channel on pancreatic β-cells → membrane depolarisation → Ca²⁺ influx → insulin release. Insulin secretion is NOT glucose-dependent → hence hypoglycaemia risk.

Indications

Type 2 diabetes (when metformin insufficient/not tolerated, or osmotic symptoms)

Adverse effects

Hypoglycaemiaclassic

Can be prolonged/severe (esp. elderly, renal impairment, long-acting agents).

Weight gaincommon

SIADH/hyponatraemia (rare)common

Cautions & contraindications

Significant renal/hepatic impairmentrenal

Prolonged hypoglycaemia.

Caution in the elderly / those who drive / skip mealselderly

Interactions

Additive hypoglycaemia with insulin/GLP-1, alcohol
Miconazole oral gel ↑hypoglycaemia

Monitoring & kinetics

HbA1c; hypoglycaemia awareness

Oral. Gliclazide preferred (shorter-acting, hepatic metabolism).

Choosing it

true

Source: NICE NG28 — T2DM · BNF — Sulfonylureas