NPH Insulin Dosing for Post-Transplant Patient on Steroids
Start NPH insulin at 10-12 units given in the morning to match the peak hyperglycemic effect of prednisone, with close monitoring for hypoglycemia given the patient's impaired and fluctuating renal function. 1, 2
Rationale for Initial Dose Selection
The American Diabetes Association recommends starting NPH at 0.1-0.2 units/kg/day for patients with impaired renal function, which for this patient (assuming ~70 kg) would be 7-14 units 2
Given this patient is currently on Lantus 12 units plus a 2-unit insulin drip overnight (total ~14 units basal insulin), and considering the addition of prednisone 5 mg, an initial NPH dose of 10-12 units is appropriate 1
Morning administration of NPH is specifically recommended for steroid-induced hyperglycemia because its 4-6 hour peak action aligns with the peak hyperglycemic effect of glucocorticoids 1
Critical Considerations for Renal Impairment
This patient has significantly impaired and fluctuating renal function (GFR 20-32), which dramatically increases hypoglycemia risk due to decreased insulin clearance and impaired renal gluconeogenesis 2
Start at the lower end of the dosing range (10 units rather than 12 units) given the renal dysfunction 2
Morning NPH administration allows better monitoring of glucose response during waking hours and reduces risk of undetected nocturnal hypoglycemia, which is particularly important in renal impairment 2
Titration Protocol
Increase NPH by 2 units every 3 days if fasting glucose remains elevated, targeting inpatient goals without hypoglycemia 1, 2
Monitor blood glucose every 2-4 hours initially given the patient is on continuous tube feeds and has unstable renal function 1
Managing the Tube Feed Coverage
The patient is receiving 242 grams of carbs per day via continuous tube feeds, which requires additional prandial insulin coverage beyond basal NPH 3
Continue the current carbohydrate ratio (1:10) for bolus coverage of tube feeds, adjusting as needed based on glucose response 3
Consider dividing tube feeds into bolus feeds if possible to allow more predictable insulin dosing, though continuous feeds are acceptable with appropriate insulin coverage 1
Common Pitfalls to Avoid
Do not give NPH at bedtime in this patient with renal impairment—the risk of undetected nocturnal hypoglycemia is too high 2
Avoid using the full 12 units of Lantus equivalent as NPH without accounting for renal dysfunction—this increases hypoglycemia risk 2
Be aware that insulin requirements will fluctuate significantly as renal function changes post-transplant, requiring frequent monitoring and dose adjustments 2
Watch for overbasalization (high glucose variability, bedtime-to-morning glucose differential) which signals need for more prandial and less basal insulin 2
Monitoring Strategy
Check blood glucose every 2-4 hours initially to assess adequacy of the regimen 1
Consider more frequent monitoring than standard given the renal impairment and post-transplant status 2
Ensure glucagon is prescribed for emergent hypoglycemia, particularly important for patients with renal impairment 2