Once you've established the maintenance dose and the cat is stable, you must implement a long-term management program. The aim is to minimize variations in insulin requirement. This includes monitoring to detect underdosage or overdosage of insulin and dose adjustment, if required. Careful monitoring during maintenance will help limit chronic problems associated with diabetes. Encourage your pet owners to monitor and record their cat's general health (including well-being, thirst, and appetite) and check urine glucose daily.
After the maintenance dose of Vetsulin® (porcine insulin zinc suspension) has been established based on the blood glucose curves, you can recheck your feline patient less frequently (every 2 to 4 months; weekly if clinical signs reappear) for general health, urine glucose, and blood glucose levels. If there is a sudden return of polyuria (PU), polydipsia (PD), or polyphagia, perform either a follow-up glucose curve or fructosamine check.
Because the albumin to which fructosamine binds degrades in the body every 14 to 21 days, fructosamine reflects the average blood glucose levels over the previous 1 to 3 weeks. Fructosamine levels in a cat's body are not affected by insulin or stress factors, so they can be taken any time of day and only a single sample is required.
If a patient shows signs of dysregulation, such as PU, PD, or polyphagia, you should conduct a full glucose curve. It's extremely important that owners are able to recognize the signs of hypo- or hyperglycemia and respond appropriately. PU, PD, or polyphagia accompanied by weight loss, general bad condition, loss of hair, abnormal furry coat, or lethargy are the most common clinical signs of hyperglycemia.
However, these clinical signs may also be present due to a rebound hyperglycemia secondary to a hypoglycemic episode (Somogyi overswing). While a blood glucose curve can help differentiate between insufficient insulin dosing and Somogyi overswing, the results can be confusing if the rebound hyperglycemia persists for a few days. Evaluating weight changes in the patient can help shed some light. If the cat is losing weight and exhibiting clinical signs of diabetes mellitus, the insulin dose may be insufficient. If the cat is gaining weight, but continues to have clinical signs consistent with diabetes mellitus, the insulin dose may be excessive, and causing Somogyi overswing.
Keep in mind that blood glucose curves at the clinic only approximate how the diabetic pet responds to insulin at home. Feeding and exercise patterns are different, and stress (especially in cats) can alter the glycemic response. So, it's critical to take into account clinical signs (or lack thereof) when you're contemplating any change in insulin therapy. The ultimate goal in regulating the diabetic pet is to control the clinical signs adequately.
Owners should understand that their cats can live healthy, active lives when their cats' diabetes is properly regulated. They should also know that diabetic cats usually require lifelong treatment with an insulin preparation, although some may go into clinical remission.