Sulfonylureas: Protecting patients from hypoglycaemia

Last updated: June 11, 2020

✦  When an oral medicine is indicated, metformin should be the first choice as per NICE guidelines because it does not cause hypoglycaemia.

✦  "Start low and go slow" when finding the right dose of any medicine for diabetes.

✦  If metformin alone is not sufficiently effective, or is contra-indicated, then consider alternatives to a sulfonylurea especially for vulnerable elderly people who are, perhaps, frail, suffering from dementia, have limited life expectancy, or who are living alone. An alternative according to NICE guidelines is one of the gliptins (also called DDP4 inhibitors). Gliptins do not cause hypoglycaemia, and can be prescribed as sole therapy or with metformin.

✦  If a sulfonylurea is prescribed for an elderly patient, avoid glibenclamide because it is longer-acting. Gliclazide, glipizide, glimepiride or tolbutamide are better choices.

✦  Consider a reasonable glycaemic target. Don't forget the Association of British Clinical Diabetologists advice about establishing an individual glycaemic target for each patient. They propose  an HbA_1c target of 7 – 8% (53 – 64mmol/mol) for patients with mild to moderate frailty, and for severe frailty, a target range of 7.5 – 8.5% (59 – 69mmol/mol).

✦  Appreciate the causes of a hypo. Explain to patients and carers what it may look like, and the precipitating factors (e.g. irregular or skipped meals, unexpected strenuous exercise, alcohol). Explain why it requires urgent attention, how to treat it at home, and when to call for medical assistance. Deteriorating kidney function, cognitive decline and frailty may increase the risk of hypoglycaemia. Be suspicious when elderly patients taking sulfonylureas have falls.

✦  Review the need for and dose of a sulfonylurea  as the patient ages. No-one should be stabilised on a sulfonylurea and expect to stay on it at the same dose for life; some patients will live with type 2 diabetes for decades. As patients age they often eat less, weigh less, have detriorating kidney function, and may develop cognitive decline. These and other factors will increase the risk of a hypo even though the sulfonylurea dose may stay the same.