hi Ella,
It's doubtful that the painkillers or the caffeine in them are causing such spikes in his sugars. I'm assuming the meds are some narcotic such as codeine or oxycodone combined with acetaminophen and caffeine --- eg, Tylenol #3 or Percocet or something like that? Caffeine is present only in small amounts in these formulas ... typically 15mg per tablet/ capsule.
A cup of brewed tea has 40mg; a cup of filtered drip coffee 135mg; 8 oz diet cola 45mg, sugar-free chocolate 45mg .. etc
Stress is well-known to send blood sugars spinning out of control for diabetics. Illness, injury and pain are definitely stressors! Stress causes the adrenals to pump out cortisols and other stress hormones. These hormones trigger the liver to produce more glycogen (glucose) to cope with the perceived threat .. the so-called "fight or flight" response. And yes, lack of exercise is likely playing a role too, especially if he's eating the same carb and calorie level and same insulin doses.
Is he having snacks in the evening or at bedtime? It's possible that he may be experiencing delayed stomach emptying ... which might be caused by the narcotic and by lack of exercise. Codeine is notorious for slowing intestinal function, that's why it causes constipation as a side effect. Delayed stomach emptying means that he's going to bed with food still in his stomach ... when this is ultimately digested and absorbed overnight, it will send the blood sugar up by morning.
Blood sugars over 10 are too high, and a sign of inadequate control. Frequent spikes and high sugars can ultimately be damaging to body systems ... tighter monitoring and control is needed. Is he following a low-carb diet? How is he taking his insulin and when? He would be wise to get his hands on a copy of
Dr. Bernstein's Diabetes Solution and read up on the chapters about normalising blood sugars and keeping them low and under control. Chapter 7 of his book is posted at his website, you might want to read it.
The Laws of Small Numbers. I recommend that he buy this book, it will be the best investment for diabetes care for the rest of his life.
hope this is helpful
Doreen