Getting Started with Insulin, or the Road to Regulation

If you are brand new to treating feline diabetes, you have two choices of when to start giving insulin.

• Because diet and insulin work hand-in-hand with each other, you may want to be sure your cat is getting good low-carb foods before you start insulin. If you choose to change diet first, please see Feeding Your Cat: Know the Basics of Feline Nutrition.

• By starting with a diet change, you will have time to collect baseline glucose levels to help interpret insulin response once you begin insulin therapy. If your cat has been exhibiting diabetic symptoms (excessive urination and drinking) for more than a month, you should start insulin therapy right away. That means you won't have any baseline data, but the sooner your cat starts insulin, the better.

When cats are first diagnosed with feline diabetes, initial blood glucose readings are notoriously poor indicators of whether higher or lower doses will be needed in the future. As hyperglycemia (high blood glucose levels) decreases from initial treatment with insulin and/or a change in diet, your cat's pancreas may begin secreting insulin on it's own. For that reason, it's important to closely monitor glucose levels so that you can reduce the insulin dose, if necessary, to avoid hypoglycemia and/or somogyi rebound.

The following steps assume that you are feeding a low carb diet and home testing.

Step 1. For the first week of insulin therapy, stick with a consistent dose and shot time, 12 hours apart. This initial "breaking in" period lets the body re-learn how to use the insulin. If you are hometesting, you will want to test before each shot and get additional tests at various times during the 12-hour cycle. The timing of your spotchecks will depend on which insulin you are using. Basically you want to know when the insulin begins to work (onset), when it peaks (lowest point), and how long before it stops being effective (duration). Dosing adjustments are made based on preshots and peaks. So make sure you get at least three (3) tests around peak time.

If your starting dose gives you peak values below 100, you may want to talk with your vet about a dose reduction.

Step 2. After the first week, share your data with your vet to determine if it's time for a dose change. This will help you and your vet communicate more clearly and may be the first time your vet has worked with someone who is home testing. If you do not feel like your vet is open to this, you can post your numbers on FDMB for review.

Here are some guidelines from 5 Steps to Regulating Your Diabetic Cat.

• If the average peak is above 150 mg/dl (8.3 mmol/L), increase the dose by 0.5 unit.
• If the average peak is between 90 and 149 mg/dl (5.0 and 8.2 mmol/L), keep the dose the same.
• If the average peak is below 90 mg/dl (5.0 mmol/L), decrease the dose by 0.5 unit.

Step 3. Repeat the cycle. However, after the first week, you may want to make dose changes every 3-4 days, especially if preshot values are remaining over 300 mg/dl. Any dose change may result in a period in which the body attempts to find a new equilibrium between glucose intake/production and insulin use. In other words, you may see higher numbers for a couple of days immediately following a dose increase. Give each new dose 3-4 days while your cat's body equilibrates or "settles" down.

Continue this approach until you begin seeing preshots no higher than 300 mg/dl and peaks close to 90 mg/dl. Many of us prefer to keep our cats more tightly regulated than this, but achieving that is beyond the purposes of this post.

These are general recommendations. Each cat and each insulin is different so you will need to customize this guidelines to your unique situation.