Is it okay to restart Janumet (sitagliptin and metformin) in a patient with an A1C of 8.5 and a GFR of 79?

Restarting Janumet in a 76-Year-Old Patient with A1C 8.5% and GFR 79

Restarting Janumet (sitagliptin/metformin) is appropriate and recommended for this 76-year-old patient with an A1C of 8.5% and GFR of 79 mL/min/1.73m².

Rationale for Restarting Janumet

Metformin Component

• Metformin remains the preferred first-line pharmacologic agent for type 2 diabetes treatment 1
• The patient's GFR of 79 mL/min/1.73m² is well above the safety threshold for metformin use
• Current guidelines support metformin use in patients with eGFR ≥30 mL/min/1.73m² 1, 2
• Metformin has beneficial effects on A1C, weight neutrality, and cardiovascular mortality compared to sulfonylureas 1

Sitagliptin Component

• DPP-4 inhibitors like sitagliptin are appropriate add-on therapy to metformin 1
• The combination of sitagliptin and metformin provides complementary and additive effects on glycemic control 3, 4
• Sitagliptin has a low risk of hypoglycemia, which is particularly important in older adults 5

Fixed-Dose Combination Benefits

• Janumet (sitagliptin/metformin) has been shown to effectively lower A1C 6
• The combination can improve patient adherence by reducing pill burden
• Studies show the combination leads to significant improvement in glycemic control 6

Treatment Considerations for This Patient

Age-Related Factors

• At 76 years old, medication safety is a priority, but the patient's A1C of 8.5% indicates poor glycemic control that requires intervention
• The patient's relatively preserved renal function (GFR 79) allows for safe use of metformin
• DPP-4 inhibitors like sitagliptin have a favorable safety profile in older adults due to low hypoglycemia risk 7

Dosing Recommendations

1. Start with a lower dose of Janumet (likely 50/500 mg twice daily)
2. Monitor for gastrointestinal side effects from metformin component
3. Titrate up as tolerated to effective dose (typically 50/1000 mg twice daily)
4. Assess A1C after 3 months to determine effectiveness 7

Monitoring Recommendations

Short-term Monitoring

• Blood glucose levels (fasting and postprandial)
• Gastrointestinal side effects (nausea, diarrhea, abdominal discomfort)
• Renal function (eGFR)

Long-term Monitoring

• A1C every 3 months until target is achieved, then every 6 months 7
• Annual vitamin B12 levels due to potential metformin-associated deficiency 1
• Renal function at least annually, more frequently in elderly patients 2

Important Precautions

When to Discontinue or Adjust Therapy

• If eGFR falls below 45 mL/min/1.73m², reassess benefit/risk of continuing therapy 2
• Temporarily discontinue during acute illness, dehydration, or procedures with contrast dye 1, 2
• Stop medication if signs of lactic acidosis develop (rare but serious): unusual muscle pain, trouble breathing, unusual sleepiness, stomach discomfort 2

Patient Education Points

• Take with meals to reduce gastrointestinal side effects
• Stay well-hydrated
• Monitor for signs of vitamin B12 deficiency (peripheral neuropathy, anemia)
• Report any episodes of nausea, vomiting, or dehydration promptly

Conclusion

Restarting Janumet is appropriate for this patient given their elevated A1C of 8.5% and preserved renal function with GFR of 79. The combination of metformin and sitagliptin provides effective glycemic control with a favorable safety profile for an older adult. Close monitoring of renal function and potential side effects remains important.