Table 3.
Type 2 diabetes: diabetic medications on a low carbohydrate diet– a summary and suggestions (36).
| Drug group | Action | Hypo risk? | Suggested action (to continue/stop) |
|---|---|---|---|
| Sulfonylureas | Increase pancreatic insulin secretion | Yes | STOP (or if gradual carbohydrate restriction then wean by e.g., halving dose successively) |
| Insulins | Exogenous insulin | Yes | REDUCE/STOP (Change to basal only and wean appropriately, e.g., successive 30–50% reductions, toward elimination) *see below |
| Meglitinides | Increase pancreatic insulin secretion | Yes | STOP (or if gradual carbohydrate restriction then wean by e.g., halving dose successively) |
| Biguanides | Reduces insulin resistance | No | Optional, consider clinical pros/cons. |
| GLP-1 agonists | Slow gastric emptying. Glucose dependent pancreatic insulin secretion. | No | Optional, consider clinical pros/cons (expensive). |
| SGLT-2 inhibitors | Increase renal glucose secretion | No | Usually stop. Concern over possible risk of ketoacidosis (though this risk may be with LADA that has been misdiagnosed as T2DM). Use in selected patients may be beneficial in early reversal. |
| Thiazolidinediones | Reduce peripheral insulin resistance | No | Usually stop. Concern over risks usually outweighs benefits. |
| DPP-4 inhibitors | Inhibit DPP-4 enzyme | No | Stop. No significant risk, but no benefit in most cases. |
| Alpha-glucosidase inhibitors | Delay digestion of starch and sucrose | No | Stop. No benefit on a low carbohydrate diet. |
There are three considerations with the use of diabetic medications in type 2 diabetes when on a low carbohydrate diet.
• Is there a risk of hypoglycaemia?
• What is the degree of carbohydrate restriction?
• Does the medication provide any benefit, and if so, do any potential benefits outweigh any side effects and potential risks?
Insulin reduction suggestion Tailor to individual. If using basal-bolus regime convert to long-acting insulin only, BD in equal doses (OD may suit some people). If a very low carbohydrate diet is planned any bolus insulin dosing can simply be eliminated. On commencing low carbohydrate diet reduce insulin by 30–50%. Monitor QDS initially for hypoglycaemia (rescue glucose if required). Continue down-titration of insulin as insulin resistance improves (can take months). Goal for most can be to eliminate insulin.
Caution: Some people with T2DM may have pancreatic insufficiency. Also people with other forms or pancreatic insufficiency (e.g., LADA or T3c) may have been misdiagnosed as T2DM. Consider this if rapidly increasing HbA1c, thirst, polydipsia, weight loss, low C-peptide. Insulin should not be eliminated in this cohort.