Management of Hyperglycemia in Post-CABG Patient Restarting Jardiance and Metformin
Immediate Recommendation
You should restart both Jardiance 10 mg and metformin immediately in this patient, as his renal function is excellent (GFR >90, Cr 0.99) and both medications are safe and indicated for cardiovascular risk reduction post-CABG, while simultaneously optimizing his insulin regimen to address the overnight hyperglycemia of 171 mg/dL. 1
Restarting Jardiance and Metformin
Safety Profile with Current Renal Function
Metformin is safe to restart with eGFR >90 mL/min/1.73 m², as the FDA-revised label contraindicates metformin only when eGFR <30 mL/min/1.73 m², with dose reduction recommended only when eGFR is 30-45 mL/min/1.73 m² 1
Jardiance 10 mg is appropriate and safe with normal renal function, as SGLT2 inhibitors are the glucose-lowering drugs of choice for patients with type 2 diabetes and cardiovascular disease, which this post-CABG patient clearly has 1
The combination of empagliflozin and metformin shows no drug-drug interactions and demonstrates bioequivalence between fixed-dose combination and individual tablets 2
Cardiovascular Benefits Post-CABG
SGLT2 inhibitors with demonstrated cardiovascular risk reduction should be prioritized as second-line agents after metformin in patients with established atherosclerotic cardiovascular disease (which CABG status confirms) 1
The EMPA-REG OUTCOME trial demonstrated that empagliflozin combined with metformin reduces major cardiovascular events, mortality, and renal outcomes in patients with type 2 diabetes and established cardiovascular disease 2
Optimizing Insulin Regimen for Overnight Hyperglycemia
Basal Insulin Adjustment
Increase Lantus by 4 units (from 30 to 34 units) immediately, as the overnight blood glucose of 171 mg/dL indicates inadequate basal insulin coverage, and the titration algorithm specifies increasing by 4 units every 3 days when fasting glucose is ≥140 mg/dL 3
Continue titrating Lantus by 4 units every 3 days until fasting/overnight glucose consistently reaches 80-130 mg/dL 3
For this 83 kg patient, the current Lantus dose of 30 units represents only 0.36 units/kg/day, which is at the lower end of typical requirements and has room for escalation 3
Prandial Insulin Coverage
Continue the current "1 per 15" carbohydrate ratio (1 unit per 15 grams of carbohydrate) for mealtime coverage, as this appears to be working adequately given the focus is on overnight hyperglycemia rather than postprandial excursions 1
Monitor 2-hour postprandial glucose readings to ensure prandial coverage remains adequate after adding Jardiance, which will provide additional glucose-lowering through urinary glucose excretion 4
Expected Synergistic Effects
Glycemic Control
The addition of empagliflozin to metformin provides HbA1c reduction of approximately 0.6-0.7% with minimal hypoglycemia risk 5, 6
Empagliflozin as add-on to metformin-based therapy led to sustained reductions in HbA1c and weight over 76 weeks in clinical trials 6
Weight and Blood Pressure Benefits
Expect weight reduction of approximately 2 kg over 6 months with empagliflozin addition, which is beneficial given the patient's BMI of 28 5, 6
Empagliflozin 10 mg may provide modest blood pressure reductions (systolic BP reduction of 2-4 mmHg), though this effect is more consistent with the 25 mg dose 6
Monitoring Requirements
Short-Term Monitoring (First 2 Weeks)
Daily fasting blood glucose monitoring is essential during insulin titration, with adjustments every 3 days based on fasting glucose readings 3
Monitor for signs of volume depletion or hypotension when initiating Jardiance, particularly in the immediate post-CABG period, though risk is low with normal renal function 4
Check for genital mycotic infections (4.1% incidence with empagliflozin 10 mg) and urinary tract infections (increased incidence compared to placebo) 4
Ongoing Monitoring
Reassess renal function within 2-4 weeks after starting Jardiance, as SGLT2 inhibitors cause acute hemodynamic changes with small increases in serum creatinine (mean increase 0.01-0.02 mg/dL) that typically reverse after discontinuation 4
Monitor for hypoglycemia, particularly 2-4 hours after prandial insulin administration, and reduce insulin doses by 10-20% if hypoglycemia occurs 3
Recheck HbA1c in 3 months to assess overall glycemic control with the combined regimen 7
Critical Pitfalls to Avoid
Insulin Management Errors
Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day (approximately 40-80 units for this 83 kg patient) without addressing postprandial hyperglycemia with prandial insulin adjustments, as this leads to "overbasalization" with increased hypoglycemia risk 3
Avoid delaying insulin dose adjustments—titrate every 3 days during active optimization rather than waiting weeks between changes 3
SGLT2 Inhibitor Precautions
Educate the patient about euglycemic diabetic ketoacidosis risk, particularly if he develops poor oral intake, acute illness, or undergoes procedures requiring fasting, as SGLT2 inhibitors can cause DKA even with normal blood glucose levels 1, 4
Temporarily discontinue Jardiance in settings of reduced oral intake, fluid losses, or acute illness to prevent volume depletion and acute kidney injury 4
Metformin Safety
Discontinue metformin before any iodinated contrast imaging procedures if eGFR <60 mL/min/1.73 m² (not applicable to this patient currently), and reassess renal function before restarting 1
Monitor for vitamin B12 deficiency with long-term metformin use, as deficiency can worsen neuropathy symptoms 1
Expected Outcomes
With optimized insulin titration and addition of empagliflozin and metformin, expect fasting glucose to reach 80-130 mg/dL within 2-3 weeks and HbA1c reduction of 1.0-1.5% over 3 months 3, 5
The cardiovascular benefits of this regimen extend beyond glycemic control, with potential reduction in major adverse cardiovascular events based on EMPA-REG OUTCOME trial data 2