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Insulin calculation

MarcR

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Is there a right way to calculate insulin dosage based on carbs? I'm trying to advise someone whom I think has been taking too much then their blood falls so low they need to eat something to bring it back up.
 
There are a number of factors involved with insulin dose calculation
  1. starting BG
  2. insulin sensitivity - how much does 1 unit of insulin reduce your BG by?
  3. insulin to carb ratio - how many grams of carbs do you need for 1 unit of insulin?
  4. plans - are you about to do something that needs more (e.g. stressful) or less (e.g. cardio exercise) insulin?
  5. insulin on board - do you have any active fast acting insulin in your body
Points 2 and 3 plus the impact of points 4 and 5 differ from person to person.
It is not something I would feel confident teaching someone else and I have been doing it for 20 years.

If someone's Bg always falls to the point of needing carbs to bring it back up, I agree they are taking too much insulin but that could also be a problem with their basal insulin or they could be on their honeymoon where their remaining insulin producing cells can temporarily spring back into life. It is not necessarily their insulin based on carbs that is too high.
 
I think it would be wise to advise them to come here rather than try yourself as what they could do will depend on numerous factors and people do have the habit of not telling the whole story so it would be easy to give misleading information.
 
They have had diabetes for about 35 years.
All that tells me is that they are very unlikely to be in the honeymoon phase but it tells me nothing about their insulin to carb ratios, insulin sensitivity, impact of exercise on their BG, whether they have the correct basal dose, etc.
As is often mentioned on this forum, the first step with working out insulin doses is to ensure you have your basal correct. This can be done through basal testing. And bear in mind, our insulin needs vary over time - your friend may have done this in the past but that does not mean it is correct now.
I think of basal as the "insulin foundation". Just like a house, if your foundation is wrong, you are building on an unstable base.
However, I appreciate you are trying to help them but I think the best advice is to talk to their DSN and explain that they need to regularly need something to bring their BG up.

I think it would be wise to advise them to come here
Sorry @Leadinglights but I disagree. We cannot provide the personal information needed.
 
In the early days I found Gary Schneider’s “Think like a Pancreas” immensely helpful in understanding insulin needs. Having the basic understanding really helps in calculations.
 
Can they ask their medical team, that would be my first bit of advice that they phone their hospital team, not GP.
 
Is there a right way to calculate insulin dosage based on carbs? I'm trying to advise someone whom I think has been taking too much then their blood falls so low they need to eat something to bring it back up.

Your advice should be for them to phone their diabetes team and also join this forum 🙂

Is this a recent problem for them? If so, that seems strange after 35 years. Has anything changed, eg hormones if they’re a woman? Change of insulin? Weight loss?
 
Your advice should be for them to phone their diabetes team and also join this forum 🙂

Is this a recent problem for them? If so, that seems strange after 35 years. Has anything changed, eg hormones if they’re a woman? Change of insulin? Weight loss?
They got diabetes in their mid 50s, ok with technology but still learning, from what I've observed most meals 40g of carbs but takes 10-12 units. Prescribed 16 units per meal.
 
They got diabetes in their mid 50s, ok with technology but still learning, from what I've observed most meals 40g of carbs but takes 10-12 units. Prescribed 16 units per meal.
Which insulins are they using?
Who supports them with their diabetes management? ie GP, nurse at GP practice or diabetes clinic?
Are they Type 1 or Type 2?

When were they told to take 16 units with each meal? ie How long ago?
When was the last time their doses were reviewed by a medical professional?

Insulin needs change over time and in response to a number of different situations and need to be reviewed quite regularly to manage things well. Illness, alcohol, exercise/activity, other medications, stress, lack of sleep, ambient temperature are all things which impact our insulin needs along with many others, so it is pretty complicated to sort your own needs out even when you are knowledgeable and confident and you live with yourself 24/7 so know exactly what you have eaten and drank and what activity you have done yesterday and today.
You estimating that they eat about 40g carbs on the occasions that you see them eat is only a very small part of the equation and that equation is a mixture of maths and the "dark arts". I would not encourage anyone who doesn't have extensive understanding of using insulin to advise someone else on making adjustments. They really need to seek advice from a knowledgeable HCP like a DSN or consultant. I personally would not trust a GP to give me advice on dose adjustment as they simply do not know enough about it unless perhaps they have diabetes themselves or have specialised in diabetes and then come back to general practice.
 
They got diabetes in their mid 50s, ok with technology but still learning, from what I've observed most meals 40g of carbs but takes 10-12 units. Prescribed 16 units per meal.
Age of diagnosis is irrelevant in terms of dosage and number of units of insulin is very personal.
For some people 10 -12 units is a lot. For some people it is low.
Maybe they have not been taught to carb count - some people are advised to take fixed doses and for various reasons do not adjust their dose according to what they eat.

Oh, and just to add to the complexity, I have just through of another factor to consider when calculating insulin doses for those of us who carb count
6. insulin to protein ratio - if we eat a low carb meal, we also need to consider the protein. But this part of the bolus is typically taken later.

It has been mentioned a few times but I will repeat it - they need to talk to the professional who looks after their diabetes care such as a DSN.
 
They got diabetes in their mid 50s, ok with technology but still learning, from what I've observed most meals 40g of carbs but takes 10-12 units. Prescribed 16 units per meal.

If they got diabetes in their mid 50s and have had it 35 years, they must be quite elderly. Insulin usage sometimes declines as people get older. So your friend might need less insulin now than they did in their 50s even if they’re less active.

I urge them to speak to their team for advice. They can run through their insulin doses and make some more tailored suggestions. It might be that their basal/slow insulin needs adjusting too.

If they were prescribed a fixed dose of insulin for meals then it sounds like they don’t know how to carb count and adjust their mealtime insulin. There are courses that would help them do this, or, if they prefer, the diabetes team could simply review their fixed dose and adjust it.
 
Mixed insulin? Fast acting one? Slow release one? Precisely the same amount of bodily movement every single day? Ditto same food and drink, ditto same germs viruses, pollen etc in the air they breathe in? If he's a bloke, same colour socks and either sex, underwear?

(er, men have changeable hormones too sometimes - not as simply predictable timing as female ones is all - or with such common noticeable bad effects!)
 
Mixed insulin? Fast acting one? Slow release one? Precisely the same amount of bodily movement every single day? Ditto same food and drink, ditto same germs viruses, pollen etc in the air they breathe in? If he's a bloke, same colour socks and either sex, underwear?

(er, men have changeable hormones too sometimes - not as simply predictable timing as female ones is all - or with such common noticeable bad effects!)
Non- blokes wear socks as well.
 
For some people 10 -12 units is a lot. For some people it is low.
Yeah 16 units for me would be around 160g carbs, more carbs at tea time. It all varies by person massively.
 
Mixed insulin? Fast acting one? Slow release one?

That was my thought too Jenny!

We can’t comment on that dose unless we know what insulin it is, and a lot more about the context.

16 units would be a fairly high insulin:carb ratio if it’s rapid acting on MDI

But 16 units would be a very different dose if it’s mixed insulin.

This basic overview might help your friend start to understand the connection between insulin and counting carbohydrates for meal doses @MarcR

 
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