The Ins and Outs of Insulin Therapy
You can combine different types of insulin, just as you can mix other drugs to take advantage of their different effects.
The plan that you and your doctor work out together will have to factor in a lot of elements-including how much you exercise (and when), what’s on your meal-plan menu, and whether you’re able to eat meals at a regular time each day.
Expect there to be a certain amount of guesswork at first. Everyone’s body responds to insulin differently, so your personal onset, peak, and duration times may be slightly different from the averages. You’ll always need to keep close tabs on your blood sugar with self-monitoring to find out exactly how you respond to the therapies you try.
Ultimately, though, deciding on an insulin plan comes down to two fundamental concerns:
- Making sure your body has enough insulin readily on hand to respond to blood-glucose levels as they rise and fall throughout the day
- Making sure you don’t get caught with too much insulin in your system during times when your blood sugar is low-a surefire recipe for hypoglycemia
It’s a tricky balance, but one that’s worth striving for. Remember that the breakthrough Diabetes Control and Complications Trial found that people who kept their blood sugar in tight control reduced their risk of such complications as eye, kidney, and nerve disease by half or more. But the study also underscored the fact that tight control makes it easy for blood sugar to plummet too low.
The trick to keeping blood sugar low but not too low largely comes down to timing. The insulins you choose need to peak when your blood sugar is rising. There are a number of ways to achieve this, and the plan you choose depends partly on how many shots you want to administer each day. Naturally, you’re not jumping up and down for more shots. But better control-which equals better health-requires more injections as a rule. Here’s how insulin plans can vary, depending on how often you inject.
One Shot a Day
Frankly, you can call this the “dream on” plan. One injection is sometimes adequate for people with type 2 diabetes, but it simply won’t be enough to meet your needs if you have type 1. Consider your theoretical options:
- A short- or rapid-acting insulin at breakfast would kick in quickly and handle the glucose from your orange juice and cereal, but it would pass its peak by lunch and leave your blood sugar unacceptably high for the rest of the day and night.
- An intermediate-acting insulin at breakfast would become active in time for lunch but leave you with zero coverage for breakfast-unless you like eating in the midmorning. By evening, the dose would be fading, and you’d still have the whole night ahead.
- Taking a long-acting insulin at the beginning of the day wouldn’t provide enough “oomph” to keep your blood sugar from spiking after you eat.
- You could mix short-, intermediate-, or long-acting insulins in the same syringe (check with your doctor for the proper procedure), but you’d still find yourself short at some point later in the day or night.
Two Shots a Day
With twice the shots comes twice the coverage-but there are still some gaps you’d be better off filling. Your doctor may advise against settling for a two-shots-a-day plan, but your success depends on how well you comply with your regimen, and the choice is ultimately up to you.
The split dose.
With a “split dose” program, you inject yourself with intermediate-acting insulin twice: once in the morning (half an hour or more before breakfast) and again in the evening (half an hour or more before dinner). That way, as the action of the first dose is fading, the second dose is ramping up. Unfortunately, this means there’s a point at which neither dose is up to full power-typically just about dinnertime, when you could use more, not less, insulin. Still, because the second dose peaks in the evening, you’ll get the nighttime coverage you need, although the insulin starts to get thin as dawn approaches. Again, breakfast may need to wait until the insulin starts taking effect.
The mixed split dose.
For better coverage, you have a second option called the “mixed split dose,” which follows the same injection schedule as the split dose. The difference is that instead of taking just an intermediate-acting insulin like NPH, you add some short-acting regular, lispro, aspart or glulisine insulin to your syringe. It will keep blood sugar under control when you inject at breakfast (which means you can eat sooner) and dinner, while the intermediate peak covers lunch.
You can mix the short- and intermediate-acting insulins in any combination you want. This allows you to adjust the proportions according to your responses or needs-say, if your blood sugar is extra high before a meal or you want to have a second piece of pie and need more insulin to handle it. For the sake of convenience, some insulin products come premixed, typically combining 70 to 75 percent NPH with 25 to 30 percent regular, lispro, or aspart.
In theory, these plans sound good. In practice, however, few patients who use them are able to achieve good enough blood-sugar control to meet currently recommended glucose targets. And although they free you from more injections, they can seem limiting in other ways-particularly by locking you into specific mealtimes every day.
Three Shots a Day
This really is the minimum standard of care for type 1 diabetes. More shots means more control because you can use short-acting insulin to counteract the effects of a meal or snack, you have more freedom to eat when you want, and you can quickly correct blood-sugar highs revealed to you by self-testing.
Three-shot plans take a number of different forms that you’ll want to discuss with your doctor. One is similar to the mixed-split-dose plan except that you take the second dose of intermediate-acting insulin at bedtime instead of dinner for better coverage at night. At dinner you take a third shot of short-acting insulin. Another alternative is to use long-acting insulin in the morning plus a short-acting insulin at every meal.
Even people who take three shots a day often find themselves adding a fourth or even a fifth injection to achieve ideal control. This is the pinnacle of insulin treatment, sometimes referred to as intensive therapy or management. It’s not for everyone because of all those shots, plus the extra finger-sticking glucose monitoring that goes with them. But if you’re intent on doing all you can, these regimens usually work the best.
Freedom and flexibility.
The aim of intensive therapy is to make your life easier, not harder. The assumption is that you’re not a robot doing exactly the same every day. Rather, you might have a late lunch if you’ve been out shopping, eat a bit more with your coffee when the in-laws come to visit-even (gasp!) skip a workout. Intensive therapy lets you do it all without throwing off your program because responding to what’s actually happening in your life is the program.
One traditional approach to intensive therapy is to take an intermediate-acting insulin (typically NPH) twice a day: in the morning (with a short-acting insulin to cover breakfast) and at bedtime. Added to that are two short-acting insulins that you inject when you eat. The dosages of the four shots should be adjusted according to how active you are or how much carbohydrate you eat. Many doctors now favor replacing NPH in this plan with the long-acting insulins glargine and detemir, which cover early-morning insulin needs better and maintain a steady “peak-free” basal insulin that’s closer to what you’d get with a normal pancreas.
Pumping up your options.
Not keen on injections and can’t use inhaled insulin? Consider an insulin pump (see page 160), which provides a continuous infusion of insulin. These devices, which can be hung on a belt or worn around the neck, hold a small reservoir of insulin that’s dispensed through a catheter in your abdomen.
Intensive therapy’s main drawback is the added risk of hypoglycemia that comes from keeping blood sugar consistently lower. You’ll need to be alert to the signs (sweating, nervousness, rapid heartbeat) and be prepared with carbohydrate snacks. If you have persistent problems with hypoglycemia, see your doctor about adjusting your insulin dosage.
Insulin and Type 2
Studies find that intensive blood-sugar management is just as helpful in preventing complications with type 2 diabetes as it is with type 1. Fortunately, the experience will probably feel a little less intense if you have type 2 because you’ll likely be able to get by with fewer insulin injections, at least to begin with.
Remember, if you have type 2, the pancreas is usually still able to pump out some of the insulin your body needs, so injections are most often started as a last resort after diet, exercise, and oral drugs or exanitide no longer suffice. But you may want to talk with your doctor about starting insulin before your blood-sugar control deteriorates to that degree: Some research suggests that taking it sooner can help preserve the function of insulin-producing beta cells in the pancreas.
If you follow standard treatment patterns, though, your insulin therapy will typically begin with an evening dose of intermediate- or long-acting insulin, often combined with a sulfonylurea to cover your daytime needs-a therapy sometimes called BIDS, for “bedtime insulin, daytime sulfonylurea.”
Eventually, most people with type 2 will need to step up their insulin regimen so that it resembles treatment for type 1, although this may not happen until you’ve had diabetes for 15 or 20 years. Most likely, treatment will then consist of two injections a day-usually a mix of short- and intermediate-acting insulin at breakfast and bedtime. If that’s not enough to meet your blood-sugar targets, you’ll need to work out a multiple-injection plan with your doctor. Because blood sugar naturally tends to be more stable with type 2, your risk of hypoglycemia with intensive therapy isn’t as great as it is with type 1.