There are 2 categories of insulin: fast-acting and slow-acting. Fast-acting insulin is mostly prescribed for humans with a bad case of diabetes and as emergency medication.
ProZinc is a slow-acting insulin specifically developed for cats. It acts over a time of 10 - 14 hours (according to the manufacturer). That means, as long as your cat eats anything at all, he should be fine.
The reason why he's supposed to eat something before the shot is probably to:
- Make sure he isn't ill and will refuse to eat after he got the insulin, which would definitely worsen his condition.
- Emulate the natural rise and fall of the insulin level in a healthy cat.
I had a look at the product information sheet and it states:
The dose should be given concurrently with or right after a meal.
Your vets might have some experience with other cats or other types of insuling that prompted them to give the advice they gave you, but your cat should be fine even if you give the shot during or right after feeding.
Since you are just starting with the insulin therapy, you should watch out for sings of hypoglycemia and probably offer him some food throughout the whole day (if you cannot be with him)
ProZinc insulin, like other drugs, may cause some side effects. Serious side effects can occur with or without warning. Please contact your veterinarian immediately if you think your cat has a medical problem or side effect from ProZinc therapy. The most common insulin-related side effect is low blood glucose (hypoglycemia). Signs of hypoglycemia may occur suddenly and can include:
- Weakness
- Muscle twitching
- Depression, lethargy, sluggishness
- Seizures
- Staggering gait
- Coma
- Behavioral changes
- Death
What actions do I take if my cat shows signs of hypoglycemia?
- If your cat is unconscious or having a seizure, this is a medical emergency.Take your cat to the veterinarian immediately.
- If your cat is conscious, rub approximately 1 tablespoon of corn syrup or honey on your cat’s gums. When it is able to swallow, give corn syrup or honey by mouth until your cat is alert enough to eat. Feed the usual meal and contact your veterinarian.
As with any medication, ProZinc is not free of adverse effects. Things to watch out for include:
In a 45-day effectiveness field study, 176 cats received ProZinc insulin. Hypoglycemia (defined as a blood glucose value of < 50 mg/dL) occurred in 71 of the cats at various times throughout the study. Clinical signs of hypoglycemia were generally mild in nature (described as lethargic, sluggish, weak, trembling, uncoordinated, groggy, glassy-eyed or dazed). In 17 cases, the veterinarian provided oral glucose supplementation or food as treatment. Most cases were not associated with clinical signs and received no treatment. One cat had a serious hypoglycemic event associated with stupor, lateral recumbency, hypothermia and seizures.
[...]
The following additional clinical observations or diagnoses were reported in cats during the effectiveness field study: vomiting, lethargy, diarrhea, cystitis/hematuria, upper respiratory infection, dry coat, hair loss, ocular discharge, abnormal vocalization, black stool, and rapid breathing.
If your cat doesn't want to eat, vomits or has diarhea, you should call you vet and ask if you should adapt the dosage of insulin.
And, as with all types of insulin, don't forget to mix the liquid before administration:
ProZinc insulin should be mixed by gently rolling the vial prior to withdrawing each dose from the vial.
You simply put the vial vertically between both hands and rub them gently together, like a child working putty into a snake. Never shake the vial! That introduces bubbles and can result in inaccurate dosages.
