What's the next step for a 71-year-old female diabetic patient with hyperglycemia, who has shown no response to metformin (biguanide) 1000mg twice daily, and is experiencing dizziness while on Amlodipine (calcium channel blocker) for hypertension?

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

Follow-Up Timeline

• Reassess in 3-5 days to evaluate blood pressure control and insulin titration
• Check HbA1c in 3 months to assess overall glycemic control 2
• Monitor vitamin B12 levels periodically given long-term metformin use 2