Feline Insulin Routine: 12-Hour Clock, Sites, Storage

Two injections a day, 12 hours apart, at the same clock times every day, is the whole routine. Food goes down before the needle, the dose comes from the vet's glucose curve and never from a home guess, and the vial lives at 2-8 °C. What the owner controls is timing, site rotation, storage and catching the 3 signs of low blood sugar early.

The 12-hour clock beats everything else

Pick 2 times 12 hours apart, for example 07:00 and 19:00, and hold them within 30 minutes every day, weekends included. Insulin action curves overlap, so a 2-hour drift on Saturday becomes a 2-hour shift in the overlap on Sunday. Feed 20-30 minutes before the injection so you know the cat has eaten; a cat that refuses more than half its meal should not be injected on the usual schedule, and the vet decides what replaces it. Log the actual times for 7 days and look at the spread, not the average.

Storage: 2-8 °C, and never the freezer

Keep the vial in the middle of the fridge at 2-8 °C, not in the door shelf, where the temperature swings 3-4 °C every time the door opens. Never freeze it: a frozen vial is dead, and thawing does not bring it back. Write the puncture date on the label, because most vials are good for 28 days after the first needle and 28 days pass faster than owners expect. Roll the vial between your palms 10 times to mix; shaking makes bubbles that throw the draw off. Cloudy, clumped or discolored insulin gets replaced, not used, and a vial left out at room temperature is finished at 28 days at most.

Site rotation: 4 spots and 1 map

Subcutaneous insulin goes into 4 places: left shoulder blade, right shoulder blade, left flank, right flank. Rotate in a fixed order so each site rests 3 days, keep every injection at least 2 cm from the last one, and never use a site that is lumpy, scabbed or bruised, because absorption from scar tissue is unpredictable. Lift a tent of skin, insert at 45-90 degrees with the needle your vet specified, release the tent, count 3 seconds, withdraw. If the skin is wet afterwards, part of the dose went into fur: write it down, do not repeat the injection, and call the vet.

3 checks before every injection

First, appetite: did the cat eat, and how much of the bowl. Second, the vial: date written on the label, contents clear, no particles, no colour shift. Third, hardware: a new needle every time, and the same syringe type printed on the prescription, since the 2 common syringe scales are not interchangeable and mixing them can deliver 2.5 times the intended volume. Do the 3 checks in the same order every time, out loud if someone else in the house also injects, so a skipped step is noticed before the needle, not after.

The 3 low-blood-sugar signals

Number 1 is trembling, weakness and a walk that looks drunk. Number 2 is glazed eyes, a head tilt, staring at a wall, or a cat that does not seem to recognise you. Number 3 is drooling, vomiting, then seizure or collapse. Many clinics treat any reading under 3.9 mmol/L (70 mg/dL) as low, and visible signs usually start under 2.8 mmol/L (50 mg/dL). If you see any of the 3, rub a small amount of glucose gel or honey on the gums, do not force food into a cat that cannot swallow, recheck in 10-15 minutes, and call the vet. The next injection waits for the vet's instruction.

The daily clock, hour by hour

Time	Action	Offset from injection, min	Record
06:30	Weigh and refill water	minus 30	Weight in kg
06:40	Serve the morning meal	minus 20	Grams eaten
07:00	First injection	0	Site used
07:05	Write the log line	plus 5	All 5 fields
12:00	Water and urine check	plus 300	mL drunk
18:40	Serve the evening meal	minus 20	Grams eaten
19:00	Second injection	0	Site used
22:00	Last behaviour check	plus 180	Alert or dull

What the log needs, 5 fields

A 7-day page with 5 columns catches more problems than any app: injection time to the minute, site, percentage of the meal eaten, water in mL and urine volume, and behaviour in 1 word. Add glucose readings only if the vet asked for a home curve, and never change the dose because of one reading. Take the page to every appointment; a 7-day spread of times and appetites is what the vet uses to judge the curve.

Cost and breed baselines

Insulin, syringes and test strips usually run 40-90 USD a month depending on the glucose testing schedule, which is worth pricing in a cost calculator before committing to a 12-hour routine. Dose is set by weight and curve, so it helps to know the breed's adult range: pages such as the York Chocolate care calendar list weight bands and daily calorie targets that the vet will ask about at the first visit.

When to call the vet

Any reading under 3.9 mmol/L (70 mg/dL), or any of the 3 low-sugar signs.
2 readings in a row above 16.7 mmol/L (300 mg/dL), or glucose that stays high for 48 hours.
Vomiting 2 times in 6 hours, or no food for 24 hours.
2 missed injections in a week, or an injection that landed in fur.
Travel or a house sitter coming: plan 24 hours ahead, in writing, never a verbal handover.

Frequently asked

What happens if I inject at a different time one evening?

A single 30-minute drift is usually tolerated, but a 2-hour shift changes how much the 2 doses overlap and can push glucose too low overnight. Keep the next morning on schedule, note the actual time in the log, and call the vet if the cat is dull, trembling or off its food. Never double up to catch a missed dose.

Can I keep the insulin out on the counter for convenience?

Only if the label allows it, and only for 28 days, after which it is finished regardless of how much is left. Warm insulin stings more on injection and degrades faster in a kitchen that hits 30 °C in summer. The fridge middle shelf at 2-8 °C is the default, and the door shelf is the worst spot because the temperature swings every time it opens.

Why does the injection site matter if the needle goes in the same cat?

Absorption varies by tissue, and repeated shots into one spot build scar tissue that releases insulin unpredictably, which shows up as glucose swinging between high and low on the same dose. Four sites in a fixed rotation, at least 2 cm apart, keep absorption even. Skip any site that is lumpy, scabbed or bruised and use the next one in the order.