What is the recommended approach for resuming insulin glargine (insulin glargine) on a patient who is on Nothing by Mouth (NPO) and Total Parenteral Nutrition (TPN)?

Resuming Insulin Glargine in NPO Patients on TPN

For patients on NPO status and TPN, insulin glargine should be continued at 60-80% of the usual dose to maintain basal insulin coverage while preventing hypoglycemia. 1

Initial Approach to Insulin Management

• Continue basal insulin (glargine) even when the patient is NPO to prevent hyperglycemia and potential ketosis 1, 2
• Reduce the usual insulin glargine dose to 60-80% of the patient's normal dose to account for the NPO status 1, 2
• Monitor blood glucose at least every 4-6 hours while the patient remains NPO to detect both hyper- and hypoglycemia 1

Specific Dosing Recommendations

• For patients previously on insulin glargine who are transitioning to TPN:
  • Initial glargine dose should be approximately 50% of the daily IV insulin requirements (if the patient was on IV insulin) 3
  • For TPN patients, this initial 50% dose is often inadequate and may need to be increased by approximately 40% to achieve target blood glucose levels 3
• For patients directly transitioning from oral intake to NPO/TPN:
  • Administer 60-80% of the usual long-acting insulin analog dose 1, 2

Monitoring and Adjustment Protocol

• Check blood glucose every 4-6 hours while NPO 1
• Use short-acting insulin as needed for hyperglycemia correction 1
• Target blood glucose levels between 140-180 mg/dL for most hospitalized patients 1
• If blood glucose consistently exceeds 180 mg/dL, increase the glargine dose by 10-20% 3
• If blood glucose falls below 100 mg/dL, decrease the glargine dose by 10-20% 4

Transitioning Back to Oral Intake

• When oral intake resumes, maintain the insulin glargine but prepare to adjust the dose 1
• The transition from IV insulin to subcutaneous insulin should occur when:
  • Blood glucose levels are stable for at least 24 hours 1
  • The patient is ready to resume oral feeding 1
• Administer the first dose of insulin glargine immediately after stopping IV insulin 1
• Add rapid-acting insulin at the first meal, with dose based on carbohydrate content 1

Special Considerations

• Patients with type 1 diabetes require continuous basal insulin even when NPO to prevent diabetic ketoacidosis 2
• For patients with significant insulin resistance (requiring high IV insulin rates >5 IU/hr), maintain higher percentages of the basal insulin dose 1
• The flat pharmacokinetic profile of insulin glargine makes it particularly suitable for hospitalized patients, including those on TPN 5, 6
• Avoid mixing insulin glargine with any other insulin products 6

Pitfalls to Avoid

• Never completely discontinue basal insulin in type 1 diabetes patients, even when NPO, as this can precipitate diabetic ketoacidosis 2
• Avoid excessive dose reduction in patients on TPN, as they often require higher insulin doses due to the glucose content of TPN 3
• Be aware that patients transitioning from IV insulin to subcutaneous insulin while on TPN may require approximately 40% more insulin glargine than initially calculated 3
• Monitor for hypoglycemia, especially within the first four weeks after switching to insulin glargine 6