Your cat was diagnosed with diabetes: the first 7 days

In October 2025, our cat Manishka was diagnosed with diabetes. The first week after your cat was diagnosed with diabetes sets the rhythm for months. I walked out of the clinic with a vial, syringes, and a calendar of morning and evening injections — and with the feeling that I had already forgotten everything. Everyone’s first seven days look different, but the to-do list is the same. Here it is, day by day.

Symptoms, diagnosis and the overall picture are covered separately in the overview article: Diabetes in Cats. This one is only about the first seven days.

Day 0: what to ask the vet while you’re still in the exam room

Write the answers down in your phone right at the appointment: an hour later, the wording starts to blur. I assembled my list afterwards from fragments, because I didn’t ask everything in the room.

• Which insulin, what concentration, and which syringes to draw it up with. U40 and U100 are different insulin concentrations, and the syringe scale has to match: mixing up the syringes means giving the wrong dose.
• The starting dose for this specific cat. Don’t take a number from an owners’ chat: according to AAHA, the dose is adjusted based on the individual animal’s response, not by formula.
• When the first follow-up visit is and what to bring: your notes, the vial, your own readings if you already have any.
• How to recognise nighttime hypoglycemia — dangerously low blood sugar: lethargy, wobbliness, trembling, seizures. And what to do before you can get to the clinic if it happens.
• Whether to feed before or after the injection, what to feed over the next few days, and whether you can leave the bowl out for the day.
• What to do if the cat didn’t finish her portion, wriggled free, or you’re not sure the insulin actually got under the skin. This, along with the question of a missed injection, is best settled with the vet in advance — then, when the moment comes, you’ll have a ready-made instruction and won’t have to guess in a panic.
• Whether you need a glucose meter right away. Human meters are used, but according to iCatCare they usually read low in cats; agree on calibration and units with your vet.

Insulin types, syringes and injection technique, with no doses — in a separate article: Insulin for Cats.

Days 1–2: what to buy, how to store it, and what to decide in advance

In the first days the sugar still swings — that’s normal. Getting diabetes under control takes weeks, not days, so don’t adjust the dose yourself: clinical signs matter more than any single number, and only a vet may make decisions based on numbers.

• The insulin exactly as prescribed, and syringes matched to it precisely. Not a “similar one” and not “whatever was in stock”.
• An unopened vial is stored in the fridge; an opened one — as directed in the product’s instructions. Don’t freeze it, don’t leave it in the sun or on a radiator, and don’t shake it — unless your vet says otherwise.
• I carried the vial home from the clinic in the cold and didn’t put it next to the radiator. That’s my own precaution from my own experience; the guidelines don’t require it.
• Two alarms at the interval the vet named. I set the same intervals at work and warned my colleagues that during those minutes I was unavailable.
• I injected into the scruff or the flank and rotated the injection sites — ask your vet whether your cat needs this: the consensus guidelines give no general recommendation on it.
• If you missed an injection or aren’t sure it went in, don’t decide on your own. Agree with your vet on what to do in both cases, right at the first appointment.
• Keep glucose gel or honey at home. At the first signs of low sugar — wobbliness, trembling, lethargy — rub the gel on the gums and drive to the clinic immediately. Nothing goes into the mouth of a cat that is unconscious.

There’s no need to panic at the mere thought of low blood sugar, but it shouldn’t be underestimated either. According to iCatCare, mild hypoglycemia often resolves on its own and, if the episode isn’t severe, is almost never life-threatening — a severe episode is dangerous, which is why at any sign the routine is the same: gel on the gums and straight to the vet. A clear step-by-step for both mild and severe episodes is covered in the overview article, in the section on hypoglycemia: Diabetes in Cats.

Day 3: the first home measurement

By day three it’s worth seeing a number at home — “day 3” here is just a convenient frame; vets don’t prescribe that deadline. Stress sends a cat’s glucose soaring, so a one-off reading in the waiting room tells you very little; that’s why ISFM and AAHA recommend monitoring blood sugar at home rather than at the clinic.

• A glucose meter, test strips that haven’t expired, a lancet, cotton wool, something tasty afterwards.
• I warm the ear in advance: with a cold ear nothing worked for us. That’s a trick from my own experience; it’s not in the veterinary guidelines.
• One calm measurement beats three with a struggle. If the cat shoots for the ceiling — stop, come back later.
• Write it down: the time, the value, and what came before it — food, the injection, a car ride, guests.
• Don’t treat a “bad” number yourself, but always record it: the vet works from your records, and can’t assess how things feel.

Our first measurement went wrong: the ear was cold, the strip didn’t draw enough blood, and Manishka decided this was an attack. The second attempt that same evening worked. Since then I warm the ear beforehand and don’t start if I’m still irritated after a work call. How to take blood from the ear and which mistakes happen in the first month — in a separate article: How to Measure Your Cat’s Glucose at Home.

Days 4–7: what belongs in the log

After a week, the vet needs a series of records: without one the dose can’t be adjusted, and at night you can’t tell “lethargic because it’s hot” from “time to call the clinic”. ISFM advises starting a log as early as possible; by the first week it’s already working for you.

• Glucose: date, time, value, where the blood came from.
• Dose: which insulin, how many units as prescribed, whether the injection went in.
• Food: what she ate, roughly how much, whether there was vomiting or refusal.
• Behaviour: thirst, litter box, activity, weight. Water intake over 24 hours is one of the main at-home markers of how the cat is responding to insulin: if she’s drinking less, control is most likely improving.

A week adds up to fourteen injections, and if the records for all that time are three lines, the vet has nothing to work with. At first we had a notepad on the fridge, then a tool: at night I lost my place between the lines and couldn’t see whether Manishka had eaten before the injection. You can keep such a log in an app too — the Diabnostic log keeps readings, doses and meals in one place, and it’s easy to show those records to your vet.

How our story ended — in Manishka’s story. I won’t promise you can repeat it exactly: every cat’s diabetes runs its own course, and the first week settles nothing for good.

Sources

1. Sparkes AH, Cannon M, Church D, et al. ISFM Consensus Guidelines on the Practical Management of Diabetes Mellitus in Cats. J Feline Med Surg. 2015;17(3):235–250. — home monitoring, the owner’s log, syringes matched to insulin concentration, the hypoglycemia threshold of 3.0–3.5 mmol/l, gel or honey on the gums, water intake as a marker of control.
2. Taylor S, Cannon M, Church D, et al. 2025 iCatCare consensus guidelines on the diagnosis and management of diabetes mellitus in cats. J Feline Med Surg. 2025;27(11). — human glucose meters underreading in cats, signs and course of hypoglycemia.
3. Bugbee A, Rucinsky R, Alvarez E, et al. 2026 AAHA Diabetes Management Guidelines for Cats. J Am Anim Hosp Assoc. 2026;62:65–93. — individual dose titration, insulin storage, home monitoring over clinic curves.