I just started my cat on Lantus (glargine) insulin. I delivered the fourth dose about 1 hour and 30 minutes ago and he gets 1 unit every 12 hours. I noticed that he becomes sleepy pretty soon after getting insulin. Each time, he’s gotten super sleepy within the hour of receiving the insulin.
He won’t open his eyes but I notice that his ears will turn when I call him. He is breathing normally. Yesterday I took the trash out to distract myself from hyper focusing on him and when I came back he was waiting for me by the door and had me follow him to his resting spot and went right back to sleep.
He’s not wobbly and he doesn’t seem to be shaky (which I know are signs of hypo). My vet discouraged me from at home testing at the moment so I don’t have his numbers and he doesn’t have a glucose device like a Libre.
Is this sleepiness normal for cats starting on insulin?
Also, I was told to just feed him every 12 hours before giving insulin and a few snacks throughout the day (but no free feeding). Is that right? It seems pretty strict but I’m not an expert in this and just want a second opinion.
If it is relevant, his urination seemed to decrease almost immediately after the first dose.
Greetings, all!
This is a sub for professional veterinary advice, and as such we follow strict rules for participating.
OP, your post has NOT been removed. Please also check the FAQ to see whether your question is answered there.
This is an automated general reminder to please follow The Sub Rules when discussing this question:
Your comment will be removed, and you may be banned.
Thank you for your cooperation!
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.
Hey OP, the extreme sleepiness (barely opening eyes but responsive) after doses sounds concerning—it's a common early sign of hypoglycemia (low blood sugar) when starting Lantus/glargine.
Sources: VCA Hospitals: Lethargy is a key hypo sign with glargine → https://vcahospitals.com/know-your-pet/insulin-glargine
Cats & Diabetes: Watch for sleepiness/lethargy as hypo when starting Lantus → https://www.catsanddiabetes.com/articles/insulin-for-cats/
The quick decrease in urination is a great sign—the insulin is working to reduce blood glucose spillover into urine (polyuria resolves early with control).
Source: Cornell Feline Health Center: Reduced urine production is expected as diabetes improves → https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-diabetes
Feeding: Yes, scheduled meals (not free-feeding) are standard—feed a consistent meal ~every 12 hours right before/around insulin to prevent lows. Small snacks OK if needed, but no unlimited grazing.
Sources: Merck Vet Manual: Precise, consistent meals for cats on twice-daily insulin → https://www.merck-animal-health-usa.com/hub/vetsulin/cats/feeding-schedule-for-felines/
Ultimately my advice to you; contact your vet ASAP (today if possible) about the sleepiness—they may reduce dose or advise home testing. Don't skip doses without guidance. You're doing great noticing changes!
This response has more information than I could have asked for. Thank you so much for linking sources too.
I did end up calling my vet—just got off the phone. We came up with a plan after an extensive conversation about his eating, general behavior, etc. He has a few other conditions and medications which make me second guess everything!
I also appreciate the information on how much he should be eating and the frequency of meals. I joined a few support groups on Facebook and they seem to contradict my vet’s advice in some ways. The meals being one of those things. Obviously I’m listening to my vet, but in a moment of panic, it’s hard to think clearly. (For what it’s worth, I’m thinking about leaving those groups.)
Edit: grammar