COMMENTARY

Making the Switch: When Your Patient Can't Afford Analogue Insulin

Anne L. Peters, MD

Disclosures

January 17, 2019

I'm going to talk about switching from analogue insulin to non-analogue insulin. This is often required because analogue insulin is very expensive, and particularly when our patients reach the doughnut hole or they lose their health insurance, they may need to switch from their analogue insulin to non-analogue insulin.

Non-analogue insulin is the old-fashioned NPH and regular. Many people have not really used much NPH and regular in their patients, particularly those who are younger and who trained after the advent of analogue insulin. I trained long ago, when we started everybody on NPH and regular.

First, to review, you have to be aware of the pharmacokinetic profile of NPH and regular. NPH is basically regular insulin mixed with protamine, and as a result, it's cloudy insulin.

When your patients go to pick up their NPH insulin, you need to warn them that it will be cloudy and that it doesn't mean it's contaminated—that's what is considered normal.

Gathering the Right Tools

Non-analogue insulin is often cheapest in a vial. Walmart has historically had very low-cost non-analogue insulin, maybe Costco. Patients need to figure out in their own neighborhood where the least expensive place is. Usually, vials are cheaper than pens of NPH, and they don't even have pens of regular insulin.

Your patients are probably going to end up with vials and syringes. This means that not only do you need to prescribe the vials, but you also need to prescribe the appropriate corresponding syringes.

There are three sizes of syringes: There's a 1-cc syringe, which holds 100 units; there's a 0.5-cc syringe, which holds 50 units; and there's a 0.33-cc syringe, which holds 30 units. Those lower-dose syringes actually come with 1-unit and 0.5-unit markings.

You need to figure out how much a patient is going to be taking in a syringe, and you want to give them the right size syringe for the dose. You want to order the vials and the syringes, and then you want to educate your patients on how to use a vial and syringe. This is much more complicated than using a pen because a vial has a vacuum in it.

Patient Education

When patients draw out the insulin, unless they put air in the vial, eventually they're going to be fighting against the vacuum. They need to take their insulin syringe, draw up air to the dose that they're going to be using with the insulin, squirt the air into the vial, and then pull out the insulin that they need.

You need to have them see, really on that scale, how they need to dose the insulin. It's not that pen with the dial. Some patients who have lower vision may have trouble actually seeing the markings on the syringe.

When I have patients switching to vials, I have them bring the pieces—the syringes and the vial—and I either teach them myself how to draw it up and make sure they're doing it correctly, or I have a diabetes educator or anybody who has knowledge about doing this teach them. [This way,] you're sure your patients know what they're doing.

NPH insulin is cloudy, but it may not be in suspension. You need to tell patients that they need to mix up that NPH insulin so that it is in suspension. There are all of these different steps compared with using an insulin pen.

You may need to teach your patients how to mix NPH and regular insulin if they're going to be on a split-mixed regimen. Remember, they always draw up the clear insulin first and then the cloudy, because you can mix it in the same syringe but you don't want to contaminate the regular with the NPH. You teach them all of these things and then you've got to figure out the dose.

Figuring Out the Dose

Let's start with the basics. Say you have a patient who is doing well. The patient is on glargine insulin and takes 100 units at dinnertime. Morning blood sugar is around 130 mg/dL and A1c is 7.6. The patient can't afford the glargine and needs to switch to NPH insulin.

There are a number of things you need to think about. First, what dose should you give? Usually, it is written that you should give 80% of the dose. If the patient is on 100 units of glargine, you should give 80 of NPH—but I hesitate, especially if the A1c is 7.6.

The thing I worry about most is hypoglycemia, particularly with non-analogue insulins. Generally, we'll give a patient 60 units, and part of that is based on the A1c. If the A1c is 9, I wouldn't reduce it that much, but in a reasonably well-controlled patient, I might give a somewhat lower dose—60%, perhaps. But again, I individualize this.

The other thing to do is to move that dose to bedtime because you know that the NPH insulin is going to peak in 10-12 hours, and you don't want that to happen in the middle of the night.

I say to my patients, "Why don't we figure out what bedtime is." I'll have them take their NPH insulin at bedtime and make sure that they have a rapid-acting carbohydrate next to their bed just in case they go low. Then, I'll have them take the dose and then uptitrate to get their fasting glucose back into range.

That's how I switch a patient who's on a dose of analogue insulin in the evening to non-analogue NPH. Generally, it works pretty well as long as you are appropriately cautious and teach the patient how to use a vial and syringe and how to deal with hypoglycemia, should it develop.

Split-Mixed Regimens

Now, say you've got a patient who is taking 100 units of NPH in the evening but fasting blood sugar is still 200, and you need to switch the patient to a more complicated prandial insulin dose.

Basically, what works—and I know this is very different from what most people are used to—is to give NPH and regular before breakfast, and NPH and regular before dinner. We call this a split-mixed regimen.

How you switch from one dose of insulin to two different mixed doses can be complicated, but I tend to make this simple. I know in my heart of hearts that I love using continuous glucose monitoring and I love getting all sorts of data points. However, when I'm doing this, especially in patients who may be less educated or less engaged with their diabetes care, I simplify.

I have patients check their blood glucose levels before meals—before breakfast, lunch, and dinner—and at bedtime. If a patient won't test that much, sometimes I'll have them test before breakfast and before dinner one day, and before lunch and before bedtime the next. I'll do whatever it takes to get some data to assess the doses.

Then, I try to do something that's vaguely mathematical. I'll take 80% of their basal insulin and divide it so that they take two thirds of that dose before breakfast and one third before dinner. The before-breakfast dose is two thirds NPH and one third regular, and the before dinner dose is half and half—50% NPH and 50% regular.

I've seen endocrinologists have knockdown, drag-out fights over how to do all of this dosing, but just suffice it to say that you're going to give more NPH in the morning before breakfast and somewhat less before dinner, and you're going to give regular insulin that's mixed in before breakfast and before dinner.

Dose Adjustments

All of these doses are adjustable, so you don't really need to land on the right dose immediately. You want to get the patient on some dose before breakfast and before dinner, and then adjust the individual components.

You adjust the dose of NPH before breakfast on the basis of the before-dinner blood sugar level, and you adjust the regular insulin dose before breakfast on the basis of the before-lunch blood sugar.

Similarly, you adjust the NPH dose before dinner that affects the fasting blood sugar, and then the before-bed blood sugar is controlled by the before-dinner regular dose. You're going to be adjusting four different doses.

If you land on the right dose to start with, you're going to be doing all right, and you really want your patient to be working closely with you during this transition.

There are a couple of other factors. If a patient is on 100 units of basal insulin, I'll reduce that to 80%—so that will be 80 units—and then I'll divide that before breakfast and before dinner, and then I'll do the uptitration.

Sometimes, though, I think patients aren't taking the full 100 units. If I'm in doubt that they're actually taking 100 units, I may reduce the total daily dose to less than 80%, maybe to 60%. The key here is to make the individual dose adjustments that you need to make as the patient is on this therapy.

Lifestyle Factors

In addition to the doses, I use this time to discuss lifestyle again. If a patient eats a big bowl of cereal for breakfast every day, it's really hard to give them enough regular insulin to cover that, because the cereal starts working and their blood sugar levels start to go up before the regular insulin is going to begin to catch them.

I ask patients what they are eating for breakfast, lunch, and dinner, and then I often focus on breakfast and the notion of snacking after dinner. Many of my patients will snack after dinner, which obviously makes management much more difficult.

If I have nutrition classes available or a dietitian, I'll send patients to work with those individuals or a diabetes educator. Again, educating around the use of analogue or non-analogue insulin is very important.

If a patient starts going low at night, I may need to switch that NPH insulin from before dinner to before bedtime and keep the regular insulin before dinner. There are many ways to do this, but the key is to get a patient through the transition safely.

If they need premeal insulin, you've got to figure out a way to do it. The beauty of vials and syringes is that you can mix insulins together—you can mix the NPH and regular in the same syringe so it's two injections a day.

For some patients, the ratio of NPH to regular that they're going to get in the same syringe will approximate a premixed insulin, say 70/30, and they have 70/30 non-analogue insulin. You can give them premixed insulin if it ends up being close to the mixture that you've established is the right dose. A premixed insulin in a vial is simpler, obviously, than mixing the two kinds of insulin together.

Again, whenever you get a patient who's working with you and whose testing allows you to make these insulin dose adjustments, you can get their A1c levels down.

I'm not sure that I can easily get people down to an A1c of 6.5, but I can get most of my patients down to an A1c that's less than 8, keeping them safe and reasonably controlled on non-analogue insulin.

Key Points to Remember

This sounds really complicated, and it is—it's more complicated than using insulin pens. But it's not impossible. Remember my key points:

First, education. Make sure a patient knows how to use a vial and syringe and can accurately draw up the insulin doses that you're prescribing.

Second, be sure to give them less non-analogue insulin—less NPH and regular—than the analogue doses, just because patients may be at greater risk for hypoglycemia and there may be more variability. You want to start safe.

Whenever you're transitioning insulin, be safe. Make sure patients are educated about hypoglycemia and they're prepared to deal with it if it occurs.

Finally, dose-adjust. Make sure that patients are in touch with you or your educator, and adjust the doses until they get into the range that you want.

Along the way, reinforce lifestyle and healthy eating. Reinforce what they should ideally be eating for breakfast and talk about reducing their snacking in the evening. Be positive, because patients can do well on NPH and regular if the doses are adjusted. It may not be quite as seamless or easy as on analogue insulin, but they can do it.

For many of our patients, it's what they can afford. If it's what they can afford, it's what they need to use.

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