Every person with diabetes benefit from having glucose goals. Peaks and drops in blood glucose levels are tracked so you can figure out why they happened and how to correct them. Once you see your glucose patterns, you want to understand when your insulins are active and when they typically stop lowering your glucose so you can offset unwanted rises and falls in your readings.
This table gives the start, peak, and end times for various insulins with some explanations and typical uses for each.
|Action Times for Insulins|
|Insulin||Starts||Peaks||Ends||Low most likely at:||Usage|
|Hum/Nov/Apidra||10–20 m||1.5–2.5 h||4–6 h||2–5 h||designed to peak, covers meals and lowers high bgs|
|Regular||30–45 m||2–4 h||5–7 h||3–7 h|
|NPH||1–3 h||4–9 h||14–20 h||4–16 h||intermediate, less peaking, larger action|
|Lantus||1–2 h||6 hr||18–26 h||5–10 h||designed for flatter and longest action, background insulin action for keeping your BG flat when fasting|
|Levemir||1–3 h||8–10||18–26 h||8–16 h|
Humalog, Novolog and Apidra insulins currently give the best coverage for meals and help keep the glucose lower afterward. Their glucose lowering activity starts to work about 20 minutes after they are taken. Rises in activity are the next 1.5 to 2.0 hours, then falls off in activity over the next 3 hours. About 5 ½ to 6 hours of activity is common with these insulins. "Rapid" insulins are still too slow for many common meals where the glucose peaks within an hour and digestion is complete within 2-3 hours. Post meal spiking can be reduced by taking the injection earlier before the meal and by eating slower carbs (low glycemic index).
Long Acting Insulins
Rather than being 24 hour insulins, Lantus and Levemir are actually 18 to 26 hour insulins. At least a third of all users do not get a full 24 hours of action from these insulins. Those who experience shorter activity times may also notice more peaking in activity and a tendency to have lower readings about 6 hours after the injection. More peaking is usually associated with shorter action, and vice versa. Those who do not take their long-acting insulin at about the same time each day can experience gaps and stacking of insulin with a single injection a day. Smaller doses often mean more insulin activity at 6 hours with less at 18 hours and beyond. More peaking usually indicates less than 24 hours of activity.
If your Lantus or Levemir “wears out” before the day is done, this can cause unexplained highs close to the time the next dose is given. It can also cause low readings during its peak activity. For instance, if Lantus is given only at bedtime, night lows may become more likely. If one injection is given in the morning, high readings may occur before breakfast.
Splitting doses of "24 hour" insulins into two equal doses with half taken in the morning and the other half taken in the evening evens out dosing gaps and minimizes peaking. After splitting the dose, most people find they have better readings. There are other reasons to split doses of Lantus or split doses of Levemir.
NPH has a shorter action and more peaking than Lantus or Levemir.This can be useful at times. For example, if a teen or young adult has a Dawn Phenomenon or someone with Type 2 diabetes sees their glucose rise in the early morning hours due to release of more free fatty acids during sleep, NPH can be taken at bedtime so that its peak in action provides the extra insulin needed at this time of the night. Bedtime NPH can be combined with an injection of Lantus or Levemir at breakfast to cover the daytime hours. A bedtime dose of NPH can also be combined with two daytime injections of NPH before breakfast and lunch. For those who use a syringe, NPH can also be combined with the rapid insulin taken for a meal into a single injection.
Pumping Insulin provides much more pump information and is the most helpful book ever written on insulin use.
Using Insulin takes you step by step toward excellent control. Whether you use one injection and pills, or six injections, you'll learn far more from this book than from any other!