How long does it take for basal insulin to stop working? My son’s been trending low the whole day, dropping even after all the bolus insulin has worn off, and we decided to just turn off the basal tonight and use a combo bolus to supplement if/when he starts rising (Because of the way the pump works, the combo bolus can be a bit more precise and can be remotely activated, whereas the basal must be programmed on the pump attached to his sleeping body). But I’m wondering how long it will take before we see the effects of turning his basal to OFF?
On a pump, the basal insulin is actually fast-acting insulin delivered in very small doses, so the basal wears off just as fast as the bolus insulin. But because the pump is delivering the “basal” insulin in very small doses, turning the basal “off” can cause his blood glucose to climb pretty fast, especially at night. (Generally, you need more insulin at night, so the basal rate is higher. So cutting off the basal could cause his BG to climb pretty fast).
Does your son have a CGM? The CGM will give you a good idea if there is a pattern to his lows. But as a general rule, it is better to lower the basal rate than it is to stop it altogether.
The goal with the basal is to keep your BG stable when you’re NOT eating, so if you have a CGM, you can learn how effective his nighttime basal rate(s) is/are. In fact, getting your nighttime basal rate right is the first thing you should always check (so both of you can have a good night’s sleep). During the night, if his basal is right, his BG should rise or fall no more than 30 points. If it is falling or rising more than that during your son’s 6-10 hours of sleep, it needs to be adjusted.
Thanks. Our son does have a CGM; it’s so eye opening.
We wound up giving him fast-acting carbs and turning off his basals all night and he stayed at the same blood sugar (about 120) for almost 6 hours overnight. So either his bolus insulin lasts WAAAY longer than it’s supposed to, or because he’s still honeymooning, he may not actually need his basal insulin at night, at least on some nights. His nighttime basal is 0.05 units/hr, which is half or less what he gets during the day.
In general his basal just seems too high, but because he uses such tiny doses, the increments available for the programmed basals are just too big. Either iit causes him to rise by about 30 points an hour, or it causes him to drop by about 40 to 80 points an hour. So my new plan is to drop his basal rates by one increment and then just top up with 8-hour combo boluses…which because of how they’re delivered can provide much smaller increments than the basal rate can.
To amplify that a bit–
A normal, nonpregnant, nondiabetic person’s blood sugar management works like this: when no food is being digested and no strenuous exercise is occurring, the liver releases a slow trickle of glucose to supply energy for ongoing routine activity. Since the liver can’t predict exactly what the body will be doing from moment to moment, minor BG fluctuations occur. The pancreas consequently releases corresponding tiny corrections to dampen the fluctuations out. That’s the basal part of the equation. It’s also sometimes referred to informally as “background” insulin.
When food is consumed, the pancreases releases larger bursts of insulin to keep BG within bounds. That’s the bolus function. Once everything is digested and the blood sugar is no longer trying to rise, that process ends and we revert back to background or basal mode once again.
In a body with diabetes, either the needed insulin isn’t present at all, or else insulin resistance prevents it from doing its job. So even if no food is being consumed, blood sugar rises and keeps on rising. And when food IS consumed, it rises more (and faster).
So, closing the circle, the purpose of basal insulin, whether delivered by a needle or a pump, is to keep BG as stable as possible when not eating. The purpose of bolus insulin is specifically to deal with meals. The point of the whole exercise is to mimic as closely as possible what a “normal” body does. Thus, basal/bolus.
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In my experience it is never a wise decision to turn the pumps basal setting to OFF for more than an hour or so. Eliminating all basal insulin could be a fast track to developing ketones once the bolus insulin has worn off.
It sounds that perhaps your son is receiving too much basal insulin in the night hours. I would respectfully suggest to try adjusting the basal dosing to a temporary basal of 70 or 80 percent of the prescribed dose , and raising or lowering that amount depending on his reaction to the changes.
Thanks Pierre – yeah I definitely agree that my son needs lower basals. The issue is just because he gets such tiny doses (he’s only 2 years old and weighs like 25 pounds), there’s no way to lower the basal without making it too low – unless I rely on my pump’s “Combo bolus” feature to supplement the additional insulin he needs.
I guess the underlying question is whether there’s really anything inherently less safe about using, say, an 8-hour combo bolus in addition to a lower basal rate to effectively mimic the basal? I mean, presumably, once the combo bolus command is sent to the pump, it just keeps running like a basal program unless it’s canceled?
This is WAY out of my zone of experience, but I have heard of parents of very young children that have tiny basal requirements diluting insulin so that the pump can effectively delivery lower basal rates. It is a “recognized” procedure and you might want to explore this idea with your Endo
This is actually a time-honored technique that is not dependent on pumps. It has long been done with manual injections for precisely the same reason: to achieve smaller controlled doses than would otherwise be practicable.
The trick is that each insulin requires its own specific diluent, and not all manufacturers choose to offer them. Also, the dilution needs to be done by an appropriately certified compounding pharmacy, and there aren’t that many around, especially if you live in a rural area.
We started with a 1:10 dilution for our son when he was on injections. Unfortunately a) it’s much less stable, having to be redone every week b) we could not get any of the diluent in a pharmacy. We had to get it from our endocrinologist, who is affiliated with a hospital. c) the diluted insulin seemed to have totally different pharmacodynamics than the undiluted kind, at least for our son. We would sometimes have to prebolus him an hour in advance to get any appreciable effect, whereas with the undiluted we never wait more than 15 to 20 minutes.
We may revisit the idea of doing a 1:2 dilution, where this effect may not be so noticeable, but right now I’m not convinced that doing a combination of a lower basal plus a long-acting combo bolus is necessarily less safe than using the hard-coded basals with diluted insulin and totally new drug dynamics.