Adjusting noninsulin antihyperglycaemic drugs

Patients with type 2 diabetes not being treated with insulin should seek medical assistance in the course of an acute illness if their last two blood glucose concentrations were more than 15 mmol/L. The dose of their noninsulin antihyperglycaemic drugs may need to be adjusted.

Treatment with the following drugs or drug classes may need adjustment in patients with type 2 diabetes and an acute illness.

• Metformin may need to be withheld temporarily. Dehydration resulting from an acute illness may worsen kidney function, further reducing metformin clearance in patients with known kidney impairment and resulting in increased risk of lactic acidosis. Metformin can also worsen nausea in unwell patients. It should only be restarted when the patient is eating and drinking normally, and kidney function has returned to baseline.
• Sodium-glucose co-transporter 2 (SGLT2) inhibitors should be withheld if a patient is acutely unwell. Concurrent illness, dehydration and low carbohydrate intake increase the risk of DKA developing and SGLT2 inhibitors also increase the risk of genitourinary infections occurring. Check for the presence of blood ketones (see Ketone monitoring), regardless of the presence of hyperglycaemia. If blood ketone concentration results are not immediately attainable and DKA is suspected, it is a medical emergency and should generally be managed in hospital (see Diabetic ketoacidosis for management). SGLT2 inhibitors should only be restarted when the patient is eating and drinking normally, and kidney function has returned to baseline. For further information about SGLT2 inhibitors and DKA, see Diabetic ketoacidosis associated with sodium-glucose co-transporter 2 inhibitors.
• Glucagon-like peptide-1 (GLP-1) receptor agonists can be temporarily withheld if the acute illness causes nausea, vomiting and anorexia; GLP-1 receptor agonists can exacerbate these symptoms.
• Sulfonylureas can be continued as tolerated, but should be withheld if the patient’s blood glucose concentrations are tending towards the lower range to avoid hypoglycaemia.
• Dipeptidyl peptidase-4 (DPP4) inhibitors can be continued and are unlikely to cause hypoglycaemia.

Short-term use of insulin may be required, if feasible. The patient needs to be educated about use of insulin, appropriate blood glucose concentration monitoring and management of hypoglycaemia.