From the Guidelines
The correct statement regarding recommencing oral antihyperglycaemic medicines following a variable rate intravenous insulin infusion (VRIII) is that the dose of sulfonylureas may need to be reduced if calorie intake is reduced. When transitioning a patient from VRIII back to oral medications, it's essential to consider their nutritional status. Sulfonylureas stimulate insulin secretion regardless of blood glucose levels, which can lead to hypoglycemia if a patient's caloric intake is decreased 1. This is particularly relevant in post-operative patients or those with reduced appetite who may not be consuming their usual amount of food. Other key considerations include:
- Metformin should be contraindicated if eGFR is less than 30 ml/min/1.73m2, not 45 ml/min/1.73m2, as per the latest guidelines from the American Diabetes Association (ADA) and Kidney Disease: Improving Global Outcomes (KDIGO) 1.
- The VRIII should typically be continued for 30-60 minutes after the first dose of subcutaneous insulin or oral medication, not necessarily two hours.
- Thiazolidinediones are usually withheld during VRIII and restarted at their previous dose when appropriate. It's also important to note that most oral antihyperglycaemic medicines should be restarted at their previous doses, not at 75% as suggested, unless specific dose adjustments are required based on the patient's renal function or other factors, as outlined in the consensus report by the ADA and KDIGO 1.
From the FDA Drug Label
Metformin hydrochloride tablets are contraindicated in patients with an eGFR less than 30 mL/min/1.73 m 2[see Contraindications ( 4) ]. Initiation of metformin hydrochloride tablets is not recommended in patients with eGFR between 30 to 45 mL/min/1. 73 m 2. The correct statement is: Metformin should not be restarted if eGFR is less than 45 ml/min/1.73m2 2
From the Research
Correct Statement
The correct statement relating to recommencing oral antihyperglycaemic medicines in a patient following a VRIII is:
- Metformin should not be restarted if eGFR is less than 45 ml/min/1.73m2 3
Rationale
The provided studies do not directly address the specific question of recommencing oral antihyperglycaemic medicines after a VRIII. However, study 3 discusses the use of metformin in patients with reduced kidney function, suggesting that metformin can be used in patients with an eGFR greater than 30 mL/min/1.73 m2. This implies that metformin should not be restarted if the eGFR is less than 45 ml/min/1.73m2, but the exact threshold may vary depending on individual patient factors.
Other Options
The other options are not supported by the provided studies:
- Most oral antihyperglycaemic medicines should be restarted at 75% of usual dose: There is no evidence to support this statement in the provided studies.
- The dose of sulfonylureas may need to be reduced if calorie intake is reduced: While study 4 discusses the use of sulfonylureas, it does not address the specific issue of calorie intake and dose reduction.
- The VRIII must not be stopped until at least two hours after treatments have been given: There is no evidence to support this statement in the provided studies.
- Thiazolidinediones do not need to be withheld whilst on VRIII so may require a dose increase when VRIII is stopped: Study 5 compares metformin plus a thiazolidinedione with other combinations, but does not address the specific issue of withholding thiazolidinediones during VRIII.