What are the available medications in New Zealand for managing postprandial hyperglycemia, specifically in the classes of alpha-glucosidase inhibitors, meglitinides, sulfonylureas, DPP-4 (Dipeptidyl Peptidase-4) inhibitors, and biguanides?

Available Medications in New Zealand for Managing Postprandial Hyperglycemia

The available medications in New Zealand for managing postprandial hyperglycemia include acarbose (alpha-glucosidase inhibitor), repaglinide (meglitinide), glipizide and gliclazide (sulfonylureas), sitagliptin and saxagliptin (DPP-4 inhibitors), and metformin (biguanide).

Alpha-Glucosidase Inhibitors

• Acarbose is the primary alpha-glucosidase inhibitor available in New Zealand, which reduces postprandial blood glucose by inhibiting carbohydrate absorption in the upper small intestine 1
• Acarbose is particularly suitable for patients who consume carbohydrates as their main food ingredient and experience postprandial hyperglycemia 1, 2
• Common adverse reactions include gastrointestinal effects such as abdominal distension and flatulence, which can be minimized by starting with a small dose and gradually increasing 1
• The risk of hypoglycemia is very low when alpha-glucosidase inhibitors are used alone 1, 2

Meglitinides

• Repaglinide is the available meglitinide in New Zealand, which reduces postprandial blood glucose by stimulating insulin secretion in the early phase 1, 3
• It must be taken immediately before meals and can be used separately or in combination with other antidiabetic medications 1
• Common adverse effects include hypoglycemia and weight gain, though the risk of hypoglycemia is lower with meglitinides than with sulfonylureas 1, 3
• Repaglinide can be used in patients with renal insufficiency but requires careful monitoring 1, 3

Sulfonylureas

• Glipizide and gliclazide are the second-generation sulfonylureas available in New Zealand 1
• These medications lower glycemia by enhancing insulin secretion and can reduce HbA1c levels by approximately 1.5 percentage points 1
• The major adverse side effect is hypoglycemia, which can be prolonged and life-threatening, though such severe episodes are infrequent 1
• Second-generation sulfonylureas (glipizide, gliclazide) are associated with a lower risk of hypoglycemia compared to first-generation agents 1

DPP-4 Inhibitors

• Sitagliptin and saxagliptin are the DPP-4 inhibitors available in New Zealand 4, 5
• These medications increase endogenous levels of GLP-1 by reducing its deactivation, enhancing insulin secretion and inhibiting glucagon secretion in a glucose-dependent manner 1, 4
• DPP-4 inhibitors reduce HbA1c levels by approximately 0.4% to 0.9% 1, 4
• They have minimal risk of hypoglycemia when used as monotherapy and have a neutral effect on weight 1, 4
• Saxagliptin requires dose adjustment in renal impairment 5

Biguanides

• Metformin is the only biguanide available in New Zealand 1
• While primarily targeting fasting glucose by reducing hepatic glucose production, metformin also helps manage postprandial hyperglycemia by improving insulin sensitivity 1, 6
• It is generally considered weight-neutral with chronic use and does not increase the risk of hypoglycemia 1
• Metformin is associated with initial gastrointestinal side effects, and caution is advised to avoid its use in patients at risk for lactic acidosis 1

Combination Therapy Considerations

• For optimal management of postprandial hyperglycemia, combination therapy may be necessary 1, 7
• DPP-4 inhibitors can be effectively combined with metformin to provide comprehensive glycemic control 8
• Alpha-glucosidase inhibitors can be used in combination with biguanides, sulfonylureas, or insulin 1, 7
• When selecting medications for postprandial hyperglycemia, consider both the pharmacological properties of the compounds and the clinical characteristics of the patient 6

Clinical Pitfalls and Caveats

• When patients using alpha-glucosidase inhibitors experience hypoglycemia, glucose or honey should be used as treatments; dietary sucrose and starchy foods have poor ability to correct hypoglycemia 1
• Some DPP-4 inhibitors (saxagliptin) have been associated with increased risk of heart failure hospitalization, requiring caution in patients with cardiac disease 4
• The risk and severity of hypoglycemia with meglitinides are lower than with sulfonylureas, but still require monitoring 1, 3
• Postprandial hyperglycemia may be present even when fasting glucose levels are normal, making it important to specifically target this aspect of glycemic control 9, 10