Immediate Management: Add Basal Insulin to Metformin
This patient requires immediate initiation of basal insulin while continuing metformin, and urgent evaluation of her dizziness to rule out hypotension from amlodipine. 1
Primary Action: Insulin Initiation
Start basal insulin immediately because this patient meets multiple criteria for insulin therapy 2, 1:
- Fasting blood glucose 14 mmol/L (252 mg/dL) and random glucose >20 mmol/L (360 mg/dL) - These values exceed the threshold of 16.7 mmol/L (300 mg/dL) where insulin is strongly recommended 2, 1
- Recent catabolic symptoms (polyuria, polydipsia, weakness) indicate significant insulin deficiency requiring immediate correction 1
- No response to metformin after dose escalation to 1000mg BD suggests severe hyperglycemia that won't respond adequately to oral agents alone 2
Specific Insulin Regimen
- Initiate long-acting basal insulin (glargine or detemir preferred over NPH) at 10 units or 0.1-0.2 units/kg once daily 2, 1
- Continue metformin 1000mg BD - do not discontinue it when adding basal insulin 2
- Long-acting analogs offer less overnight hypoglycemia and possibly less weight gain compared to NPH 2, 1
Critical Secondary Issue: Evaluate the Dizziness
The new-onset dizziness requires immediate blood pressure assessment 3:
- Check orthostatic vital signs - the combination of amlodipine with improved hydration status (resolved polyuria/polydipsia) may be causing hypotension
- Measure blood pressure sitting and standing to assess for orthostatic hypotension
- If blood pressure is <130/80 mmHg or patient has orthostatic symptoms, consider reducing amlodipine dose 2
- The target blood pressure for diabetics is <130/80 mmHg 2
Important Caveat About Drug Interactions
Monitor renal function closely when using metformin with ACE inhibitors or ARBs (though amlodipine is a calcium channel blocker, not an ACEI/ARB) 4. However, be aware that acute illness with dehydration can precipitate lactic acidosis with metformin, so ensure the patient is well-hydrated 4.
Patient Education Requirements
Provide comprehensive insulin education immediately 1:
- Glucose monitoring technique - check fasting glucose daily and adjust insulin dose accordingly
- Insulin injection technique and storage - proper subcutaneous injection and refrigeration
- Hypoglycemia recognition and treatment - symptoms include shakiness, sweating, confusion; treat with 15g fast-acting carbohydrate
- Sick day rules - when to hold metformin (during vomiting, diarrhea, dehydration) 4
Titration Strategy
Titrate basal insulin every 2-3 days based on fasting glucose readings 2:
- Increase by 2 units if fasting glucose >7.0 mmol/L (126 mg/dL)
- Target fasting glucose: 4.4-7.0 mmol/L 2
- Most patients with type 2 diabetes can achieve control with basal insulin alone 2, 1
Why Not Other Options?
Do not add another oral agent at this point 2, 1:
- The glucose levels are too high (>20 mmol/L) for oral agents to be effective as monotherapy or dual therapy
- Sulfonylureas would increase hypoglycemia risk and cause weight gain 2
- SGLT2 inhibitors or GLP-1 agonists, while beneficial for cardiovascular outcomes, are insufficient for this degree of hyperglycemia 2
Do not delay insulin therapy - the American Diabetes Association explicitly warns against delaying insulin in symptomatic patients with severe hyperglycemia 2, 1