Does Codeine lower blood sugars

Maybe? At least codeine, possibly combined with morphine, were considered a treatment for diabetes (apparently reducing glucose in urine) before insulin was discovered.

I'm a type one diabetic and recently herniated a disc in my back that irritated my sciatic nerve. I suffered for as long as I could before my wife insisted that I see a doctor, who gave me a perscription for co-codamol which contained 30mg of codeine per tablet. I was advised that I could take up to 240mg of codeine per day and signed off work for two weeks.
As my job is quite physical I expected that being inactive and spending two weeks laid up would result in higher blood sugar levels. To my surprise the opposite happened, I had two weeks of steady, low readings and even took full advantage for instance having a scoop of ice cream with my lunch.
I've done DAFNE and continued to use my usual ratios and carb count, I didn't hypo at any point over the two weeks. Also due to the fact I didn't have to drive at no point did I need to raise my blood sugar. After the two weeks ended my doctor advised reducing my dose and returning to work, only light duties. Within three days I was managing my pain with paracetamol and ibuprofen only and although I'm not lifting anything I am much more active. I've seen a noticeable rise in my BG readings and the only explanation that I can see is a connection with reduction in codeine consumed.
I realise that codeine can be habit forming and I'm in no way advising anybody to use this strong pain killer to better control their diabetes. I just wanted to share my experience.

That's a lot of codeine. Constipation could become a problem. My doctor cut my codeine intake from 30gm per tablet down to 8mg and I feel better for it.

This is very interesting! I was recently prescribed Codeine and my usually well controlled bg has decreased significantly. I’ve just had my third hypo since starting the new meds inwas down as low as 2.2 interestingly our springer spaniel was really unsettled prior to me testing and up until I jelly babied up

I have just started to take cocodamol for a frozen shoulder and blood sugar has plummeted after only 2 low doses 12 hours apart. I am normally very well controlled. My freestyle libre showed reading of 4mmol but by this time blood sugar reading was actually 2.5mmol and immediate glucose needed

I was taking codeine as an alternative to amitriptyline because this also led to significant night hypos.
Warning on the information leaflets would be helpful.