Dear Daisy Dog: My dog Scrappy, who has diabetes, was doing well with twice-daily injections of Humulin-N insulin. Recently the pharmacist gave me Novolin-N insulin instead, saying they were both NPH insulin and therefore identical.

But the new insulin caused such a profound drop in Scrappy's blood sugar that he almost died.

My veterinarian told me the two insulin products differ sufficiently that they are not interchangeable in dogs. Please warn your readers to check the medications their pharmacist dispenses and alert their veterinarian if there's a change.

Daisy responds:
Other dogs have experienced the same problem, so we're glad you're pointing it out.

Many types of insulin are available to meet differing patient needs. They vary in concentration, absorption time and duration of activity, ranging from short- to long-acting.

NPH, an intermediate-acting insulin, is available in two brands, Humulin-N and Novolin-N, which differ from each other just a bit.

While they may behave similarly in humans, they don't always in us dogs.

So, once a pet's diabetes is well-regulated on one type and brand of insulin, it's important to continue using the same product.

Other causes of poor diabetic control include changes in diet or feeding schedule, altered exercise patterns, hormonal influences (particularly in female dogs that go into heat) and disorders such as Cushing's disease, dental problems and urinary tract infection.

Dear Christopher Cat: Now that spring has arrived, I'm concerned about my cat Charlie, who likes to wander through my gardens. He is particularly attracted to my beautiful foxglove plants, walking through them and rubbing his face on the bell-shaped flowers. Should I worry about this behavior?

Christopher responds:
If he only walks through the plants and doesn't ingest anything, Charlie probably will be fine. But watch for signs that he may have eaten foxglove, from which the heart medication digitalis is derived.

If ingested, foxglove can cause stomach upset, vomiting and diarrhea. But what's more worrisome is that it can disrupt the heart's normal rate and rhythm, causing life-threatening arrhythmias. Foxglove also can cause electrolyte disturbances that can impair heart function.

All parts of the foxglove plant are toxic, but the highest concentrations of digitalis are found in the flowers, fruit and immature leaves.

If Charlie displays any abnormal clinical signs, and you're afraid he may have nibbled a plant in your garden, get him to your veterinarian immediately. If you are uncertain about the names of your plants, take along flowers and leaves to help your vet identify them.

Ask the Vet's Pets appears Friday in the print edition of the Reading Eagle. The animal authors of the column live with Lee Pickett, V.M.D., who practices companion animal medicine at Bernville Veterinary Clinic. Contact them at, 610-488-0166 or P.O. Box 302, Bernville, PA 19506-0302.