Rapid-Acting Or Long-Acting Insulins?

Long-acting insulin is a slow-release insulin that works throughout the day to maintain a baseline insulin level.  A rapid-acting insulin is used to cover meals and prevent a sharp rise in blood sugar after eating.  People with Type 1 diabetes often use long-acting and rapid-acting insulin to help control blood sugar.  People with Type 2 diabetes sometimes use these insulins for blood sugar control.  Other types of insulin include intermediate-acting insulin, short-acting insulin, and ultra-long-acting insulin.  Your healthcare provider will work with you to determine your best insulin regimen.

What Is The Difference Between Rapid-Acting And Long-Acting Insulins?
By Pierre Mouchette | Bits-n-Pieces

Insulin is an essential treatment for people with diabetes.  Some insulins are long-acting, some are rapid-acting, and some are between.  For people with Type 1 diabetes, insulin is essential because their bodies do not make insulin, which leads to high blood sugar.  Injecting insulin brings their blood sugar down to safe levels.  People with Type 1 diabetes usually use a combination of long-acting and rapid-acting insulin.
For people with Type 2 diabetes, insulin is not always needed.  But it can still be a practical and sometimes necessary treatment.  Their bodies may not make enough insulin or respond normally to insulin (insulin resistance).  People with Type 2 diabetes usually start with long-acting insulin (if they need insulin).  Rapid-acting insulin may be added later on.
 
What Is Long-Acting Insulin?
Long-acting or basal insulin gives you a slow, steady release of insulin.  The insulin works throughout the day to control blood sugar between meals and overnight.  Long-acting insulin can be injected once or twice daily, depending on the specific type of insulin.  It can be used as a treatment for Type 1 and Type 2 diabetes.
 
Long-Acting Insulin Names
Sometimes, there are two or more brand names for specific insulin based on differences in formulation.  Common names of long-acting insulins include:

• Insulin detemir (Levemir)
• Insulin glargine (Lantus, Basaglar, and Semglee)

 
How Long Does Long-Acting Insulin Take To Work?
Long-acting insulin takes about 2 hours to start lowering blood sugar.  This type of insulin is designed to last a long time, so it takes longer than other insulins to begin working.  Long-acting insulin usually does not peak, maintaining a steady insulin level throughout the day.
 
How Long Does Long-Acting Insulin Last?
The duration of action (how long the medication works) varies between long-acting products.  But long-acting insulin should last up to 24 hours.  The following are the typical duration of action times for each long-acting insulin:

• Insulin detemir: 12 to 24 hours
• Insulin glargine: 24 hours

 
Should I Take Long-Acting Insulin At Bedtime?
There is no consensus on what time of day is best to inject long-acting insulin, which may differ from person to person.  Injecting your insulin at the same time each day (for once-daily dosing) is more important than the exact time of day when you inject it.  Some experts say that injecting insulin glargine at lunchtime or night, instead of bedtime, may lower the risk of high blood sugar in people with Type 1 diabetes.  You should check with your health care provider to determine the best time to take long-acting insulin.
 
Do Any Insulin Products Last Longer Than Long-Acting Insulins?
Two ultra-long-acting insulin products are insulin glargine U300 (Toujeo) and insulin degludec (Tresiba).  These insulins begin working within 6 hours of injection and last 36 to 42 hours.
 
What Is Rapid-Acting Insulin?
Rapid-acting or meal-time insulin is usually taken before, during, or after a meal to lower your blood sugar levels associated with meals.
Examples of rapid-acting insulins are:

• Inhaled insulin (Afrezza)
• Insulin aspart (Novolog)
• Insulin glulisine (Apidra)
• Insulin lispro (Humalog)

 
How Long Does It Take Rapid-Acting Insulin To Begin Working?
The onset of action (when insulin starts to kick in) varies between rapid-acting insulin products.  But they usually start working within 15 minutes, depending on the insulin.  Rapid-acting insulins last about 2 to 4 hours.
 
Do I Need More Than One Insulin?
Maybe.  It is up to your health care provider to determine the best medication regimen for you.  Some people with Type 2 diabetes may only need long-acting insulin to get their blood sugar control on track.  Others may require a combination of rapid-acting and long-acting insulins to control their blood sugar best.
If you use an insulin pump, you only need rapid or short-acting insulin.  Typically, only patients with Type 1 diabetes use an insulin pump.  The pump gives you a slow and steady amount of insulin to cover you all day like a long-acting insulin would do.  However, it is a good idea to have a backup of long-acting insulin if your pump fails.
 
Is There Anything In Between Rapid-Acting And Long-Acting?
There are short-acting and intermediate-acting insulins available.  Regular insulin (Novolin R, Humulin R) is an example of short-acting insulin.  Neutral protamine hagedorn (NPH) insulin (Novolin N, Humulin N) is an example of intermediate-acting insulin.
Short-acting insulins like rapid-acting insulin cover blood sugar elevation after eating.  Intermediate-acting insulins are similar to long-acting insulins:  They cover blood sugar elevations when the rapid-acting or short-acting insulins finish working.  But their duration of action is shorter than long-acting insulins.
 
What Are Combination Insulins?
Some insulin products combine fast-acting and intermediate-acting insulins.  The two insulins work together to help manage blood sugar between meals and at night.  They also cover blood sugar spikes that happen when you eat. A few examples of combination insulins are:

• Insulin aspart protamine and insulin aspart (Novolog 70/30 Mix)
• Insulin lispro protamine and insulin lispro (Humalog 50/50, Humalog 75/25)
• NPH insulin and regular insulin (Humulin 70/30, Novolin 70/30)

Combination insulin products typically only need to be injected twice daily since they are single insulin products that contain shorter-acting and intermediate-acting insulin.