Prescription Sig for Humalog Sliding Scale with Meal Dosing
Inject 4 units subcutaneously before breakfast, lunch, and dinner (within 15 minutes before or immediately after starting each meal), PLUS check blood glucose before each meal and add 1 unit for every blood glucose reading >130 mg/dL. 1
Prescription Format
Humalog (insulin lispro) 100 units/mL
Sig: Inject 4 units subcutaneously before each meal (breakfast, lunch, dinner). Check blood glucose before each injection. If blood glucose >130 mg/dL, add 1 unit to the 4-unit base dose. Inject within 15 minutes before or immediately after starting meal. Rotate injection sites (abdomen, buttocks, upper arms, upper thighs). Use a new needle for each injection.
Dispense: 2 vials (10 mL each) or equivalent pen devices
Refills: As appropriate
Critical Prescribing Details
Timing Requirements
- Humalog must be administered within 15 minutes before or right after eating a meal 1. This is a rapid-acting insulin with onset that requires meal coordination to prevent hypoglycemia.
Injection Technique
- Use subcutaneous injection only in stomach area, buttocks, upper legs, or upper arms 1
- Rotate injection sites with each dose to prevent lipodystrophy (pits or thickened skin) 1
- Never reuse needles - always use a new needle for each injection to prevent infections and blocked needles 1
Important Safety Considerations
This sliding scale approach has significant limitations you should understand:
- Research shows sliding scale insulin alone achieves target glycemic control in only 6-12% of hospitalized patients, with 51-68% remaining poorly controlled 2
- The approach is most appropriate only for patients with mild hyperglycemia (admission glucose <180 mg/dL), where 83-86% achieve target control 3
- If blood glucose remains persistently >250 mg/dL, this regimen will likely fail and basal insulin should be added 3
Monitoring Requirements
- Check blood glucose before each meal
- Prescribe glucagon for emergency hypoglycemia - patients on prandial insulin are at risk for severe hypoglycemia 1
- Watch for hypoglycemia symptoms: dizziness, sweating, confusion, shakiness, fast heartbeat 1
When This Regimen Fails
Current guidelines recommend against sliding scale monotherapy for most patients 4. The 2025 ADA Standards recommend:
- Starting prandial insulin at 4 units per meal OR 10% of basal insulin dose 4
- Increasing by 1-2 units or 10-15% if A1C remains above goal 4
- For hypoglycemia, reduce dose by 10-20% 4
If this patient requires ongoing insulin therapy beyond acute illness, transition to a basal-bolus regimen with long-acting basal insulin plus mealtime rapid-acting insulin, as this provides superior glycemic control compared to sliding scale alone 4.