How to manage Oral Hypoglycemic Agents (OHAs) and insulin, along with hypertensive and thyroid medications, in patients undergoing medical interventions?

Management of Oral Hypoglycemic Agents, Insulin, and Thyroid Medications During Medical Interventions

For patients undergoing medical interventions, oral hypoglycemic agents (OHAs) should be temporarily discontinued, insulin regimens should be modified based on the procedure type, and thyroid medications should be continued with minimal interruption to prevent metabolic decompensation. 1

General Principles for Medication Management

Oral Hypoglycemic Agents (OHAs)

• Sulfonylureas: Discontinue 24-48 hours before procedures due to high risk of hypoglycemia 1
• Metformin:
  • Discontinue 48 hours before procedures involving iodinated contrast
  • Hold if eGFR <30 mL/min/1.73m² or in patients at risk for lactic acidosis (hypoxia, sepsis, liver failure) 1, 2
• SGLT2 inhibitors: Discontinue at least 3 days before procedures due to risk of euglycemic ketoacidosis 1
• DPP-4 inhibitors: May be continued until the day of procedure for stable patients 1

Insulin Management

• Basal insulin:
  • Reduce dose by 20-25% the evening before or morning of procedure
  • For prolonged fasting, consider further reduction to 50% of usual dose 1
• Prandial insulin:
  • Hold during fasting periods
  • Resume when oral intake is established 1
• Mixed insulin regimens:
  • Convert to basal-bolus approach during perioperative period
  • Give 80% of NPH dose as basal insulin 1

Thyroid Medications

• Continue thyroid hormone replacement with minimal interruption
• If NPO status required, consider IV levothyroxine at 80% of oral dose
• Resume oral medication as soon as oral intake is established

Specific Scenarios and Protocols

For Minor Procedures (Outpatient/Same-Day)

1. Morning procedures:

   • Hold morning OHAs
   • Give 50-75% of basal insulin
   • Resume normal regimen with first meal after procedure

2. Afternoon procedures:

   • Give morning basal insulin at 50-75% of usual dose
   • Hold all OHAs on day of procedure
   • Resume normal regimen with evening meal if eating normally

For Major Procedures (Requiring Hospitalization)

1. Pre-procedure:

   • Discontinue sulfonylureas 24-48 hours before procedure
   • Discontinue metformin 48 hours before procedure if contrast used
   • Give 50-75% of basal insulin the evening before or morning of procedure

2. During hospitalization:

   • Switch to basal-bolus insulin regimen while NPO
   • Target blood glucose 140-180 mg/dL 1
   • Monitor blood glucose every 4-6 hours, more frequently if unstable

3. Post-procedure transition:

   • Resume OHAs only after stable oral intake and normal renal/hepatic function
   • Consider continuing insulin until glycemic stability is achieved

Hypoglycemia Prevention and Management

• High-risk patients (those on insulin or sulfonylureas) require close monitoring 1
• Treatment protocol:
  • For blood glucose <70 mg/dL: Administer 15-20g oral glucose
  • Recheck blood glucose after 15 minutes and repeat treatment until >70 mg/dL
  • For severe hypoglycemia: Use IV glucose or IM glucagon 1

Special Considerations

Total Parenteral Nutrition (TPN)

• Add regular insulin to TPN at initial dose of 1 unit per 10g carbohydrate
• Provide subcutaneous correction insulin every 6 hours as needed
• Adjust TPN insulin by 10-20% daily based on glucose patterns 3

Thyroid Disease Management

• Hypothyroidism: Continue levothyroxine with minimal interruption
• Hyperthyroidism: Continue antithyroid medications; consider beta-blockers for symptom control
• Monitor for signs of thyroid storm during stress of procedures (tachycardia, fever, altered mental status)

Transition Back to Home Regimen

1. Resume home regimen when:

   • Patient is eating regularly
   • Renal and hepatic function have returned to baseline
   • Acute illness has resolved

2. Consider medication adjustments if:

   • Pre-procedure glycemic control was suboptimal
   • Clinical status has changed significantly

Common Pitfalls to Avoid

• Relying solely on sliding scale insulin without basal coverage leads to poor glycemic control 1
• Abrupt discontinuation of TPN without corresponding insulin adjustment can cause hypoglycemia 3
• Failure to reduce insulin doses during fasting periods increases hypoglycemia risk 1
• Restarting metformin too soon after contrast procedures increases risk of lactic acidosis 2
• Overlooking thyroid medication management can lead to metabolic decompensation

By following these structured guidelines, healthcare providers can effectively manage diabetes and thyroid medications during medical interventions while minimizing the risks of adverse events and optimizing patient outcomes.