How do I adjust the insulin dose according to blood sugar levels?

A blood glucose curve is periodic testing of the blood sugar levels to see what effect the insulin is having. The values will ALWAYS vary; you are looking for values outside of acceptable ranges, which will be approximately 100-200 or maybe up to 300 depending on your cat.

In the initial stages of therapy the usual recommendation is to test blood glucose (BG) three to four times per day. See the section on urine testing for suggestions on when this testing should occur. After regulation has been achieved, routine tests before the morning meal two to three times weekly will be enough to let you know if your pet is staying regulated.

BE VERY CAUTIOUS WHEN MAKING CHANGES IN YOUR CAT'S INSULIN DOSE WITHOUT CONSULTING YOUR VETERINARIAN. My recommendation is to always consult a veterinarian before making a change. Also, once a dose change is made, give your cat 3 to 4 days to adjust to the new dose before considering another change.

Here are some rough guidelines:

1. If ALL of the BG readings are HIGH, an approximate 10% INcrease in the insulin dose can be made.
2. If ALL of the BG readings are LOW, an approximate 10% DEcrease in the insulin dose can be made. If your cat is symptomatic, the dosage may be reduced further.
3. If the readings are HIGH only before insulin is given (or around the time of the morning meal) OR at the time the insulin duration is almost over, do NOT change the dose.
4. If the readings are HIGH at BOTH the morning and evening readings, consider Somogyi effect and DECREASE the amount of insulin.
   

Interpreting the Glucose Curve*

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To determine the dosing interval or the type of insulin given, evaluate the peak time.

If the peak time is:

• <5>
• 5-8 hours continue b.i.d. (2/day) administration.
• >8 hours change to s.i.d. (1/day) administration.

To determine the dose of insulin or if dysregulation is a problem, evaluate the nadir and range midpoint.

If the nadir is <>

The ideal range midpoint is 200 mg/dI, and 150-250 mg/dl is acceptable. If the range midpoint is:

• <150>
• 150-250 mg/dl, don't change the dose.
• >250 mg/dI, several possibilities exist:
  • The cat may have been stressed when the blood glucose curve was performed.
  • The Insulin dose may be too low.
  • There may be an insulin problem (inactive insulin, insulin not mixed property, poor injection technique, poor absorption).
  • Insulin resistance may be occurring due to concurrent disease (systemic Illness, hyperthyroidism, hyperadrenocorticism, acromegaly) or insulin antibodies.

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*Based on twice-daily dosing of insulin.

**The nadir also should be below 100 mg/deciliter.