Q & A: Adjusting The Dose Of Determir Insulin In Dogs

I have an 12-year-old F/S lab who was diagnosed with diabetes 4 months ago. The dog had typical signs of polyuria, polydipdia and weight loss.

She was initially started on NPH insulin at 0.4 U/kg BID (8 U BID). Over the course of 2 months, we increased the NPH dose to 0.7 U/kg BID (14 U BID) but the dog continued to be symptomatic. We did a blood glucose curve and obtained the following results:

• Fed at 7:30 AM
• Glucose at 8:30 AM: 132 mg/dl
• Glucose at 10:30 AM: 103 mg/dl
• Glucose at 12:30 PM: 160 mg/dl
• Glucose at 2:30 PM: 286 mg/dl
• Glucose at 4:00 PM: 381 mg/dl

Based on that curve was concerned that the duration was too short, so we switched to insulin detemir (Levemir). I know that detemir is more potent, so we started at 0.1 U/kg BID (2 units BID). The blood glucose curve 1 week later:

• Fed at 7:30 AM
• Glucose at 8:30 AM: 580 mg/dl
• Glucose at 10:30 AM: 343 mg/dl
• Glucose at 12:30 PM: 364 mg/dl
• Glucose at 2:30 PM: 361 mg/dl
• Glucose at 4:00 PM: 401 mg/dl

We then increased detemir to 3 units BID, and checked again 8 days later:

• Fed at 7:30 AM
• Glucose at 8:30 AM: 422 mg/dl
• Glucose at 10:30 AM: 234 mg/dl
• Glucose at 12:30 PM: 253 mg/dl
• Glucose at 2:30 PM: 309 mg/dl
• Glucose at 4:00 PM: 381 mg/dl

We then increased to 0.2 U/kg BID (4 units BID), and checked again in 2 weeks.

• Fed at 7:30 AM
• Glucose at 8:30 AM: 422 mg/dl
• Glucose at 10:30 AM: 283 mg/dl
• Glucose at 12:30 PM: 321 mg/dl
• Glucose at 2:30 PM: 356 mg/dl
• Glucose at 4:00 PM: 370 mg/dl

We just did a complete urinalysis and urine culture which was negative. Results of a recent CBC and serum chemistry panel were normal, except for the high blood glucose concentration. The dog is doing well clinically at home.

I'm not sure what to make of the persistent hyperglycemia on detemir. Possible Somogyi reaction? Or does the dog just needs more insulin?

When increasing the detemir insulin dosage, should I be going up a certain percentage or unit/half-unit at a time?

My Response:

This certainly doesn't look like an overdose of insulin or Somogyi overswing to me. Most likely, this dog just needs more insulin.

However, you should double check the following points with the owner as the next step:

• That they can accurately measure and then inject the insulin reliably.
• That they are feeding the dog only in morning and evening (no other treats during the day).
• That they are measuring the amount of food being feed, calculated by a veterinarian that it's the correct amount for the dog's ideal body weight.

It doesn't appear clinically that she has any concurrent conditions that would cause insulin resistance, such as infection, inflammation, or Cushing's excess. Some dogs just require more insulin to adequately lower their blood glucose than do other dogs!

In a large dogs, I increase my detemir dose by increments of 1 unit BID. In a small-breed dogs, I increase by less; by increment of 0.5 units BID.

I then wait 1 week or so and then repeat the serial glucose curve to make any additional needed dose adjustments.