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Basal Insulins Explained

Medication Rundown Series

Many people with diabetes have developed a love-hate relationship with insulin. This life-saving, wallet-shrinking, high-fixing, low-causing, pain-to-dose wonder molecule is a mainstay of diabetes care.

There are many flavors of insulin out there so let’s start by breaking down the longer acting (basal) insulins.

How They Work

All insulins work the same once they reach their target cells all around the body. The insulin binds to a cell, causes a bunch of complicated biochemistry to happen, and ultimately this means glucose is transported from the blood into the cell. This gives the cell its much-needed glucose fuel and drops blood glucose to a lower level.

The differences between various injected insulins aren’t in what the insulins do when they get to their target. Rather, the differences are in how the insulins get to their target. Longer-acting (basal) insulins take longer to go from the injection point, into the bloodstream, and then to the cells.

The long-acting insulins take longer to move into the blood because the individual insulin molecules are all stuck together into a bigger molecule that breaks down slowly. The type of bigger molecule and how it’s formed varies by product but the general principle is the same for all basal insulins.

Basal Insulins Compared

Basal insulins are categorized based on how long it takes them to go from the injection site to the cells. They are classified as intermediate-acting, long-acting, or ultra long-acting.

Intermediate Acting Insulins — Insulin NPH

Insulin NPH (insulin protamine Hagedorn) is one of the earliest basal insulins.  It is sold under the brands Humulin N, Novolin N, Humulin 70/30, and Novolin 70/30.

Uniquely among basal insulins, NPH is available over the counter in the US as Humulin N and Novolin N.

While consumer demand for NPH insulin is currently much lower than for the newer basal insulins, NPH is one of the “cheap” insulins many people are considering as a way to avoid the high cost of newer insulins.

NPH also makes up 70% of Humulin 70/30 and Novolin 70/30. These combination insulins are good for people who have consistent diets and need a less complicated regimen.

Action Profile

  • TIme to start working: ~2 hours
  • Time to max effect: ~6 hours (varies by person/dose)
  • Time till it wears off: ~14  hours (varies by person/dose)

Good and Bad

  • Cost: $25 per vial, $0.03 per unit (Walmart, retail)
  • The good: It is cheap, OTC, and the 70/30 mixes can simplify dosing for some.
  • The bad: The timing of meals is less flexible and most people will have more highs and lows on this type of insulin.

Long Acting Insulins — Insulin detemir

Insulin detemir (Levemir) is one of the most popular basal insulins. It has a longer action than NPH but still has a peak and might not always last 24 hours. This means that many patients have to take it twice a day. This basal insulin is sometimes preferred because it doesn’t sting on injection. Unfortunately, it’s not as consistent-absorbing or “smooth” as some of the other options.

Action Profile

  • Time to start working: ~2 hours
  • Time to max effect: ~7 hours
  • Time till it wears off: ~22 hours (varies by person/dose)

Good and Bad

  • Cost: ~$480 per 5 pens, $0.32 per unit (via GoodRx)
  • The good: Longer action, more stable than NPH. Covered by most insurance. Doesn’t sting!
  • The bad: Not as stable or long absorbing as others. Many people do better dosing detemir every 12 hours.

Long Acting Insulins — Insulin glargine U-100

Insulin glargine U-100 (Lantus, Basaglar)

Insulin glargine is the most popular basal insulin in the US at this time. It has a longer and “smoother” action than NPH or Levemir and is the first insulin to reliably last 24 hours with a single injection.

Action Profile

  • TIme to start working: ~2 hours
  • Time to max effect: ~4 hours but minimal peak
  • Time till it wears off: ~24 hours

Good and Bad

  • Cost: ~$290 for 5 pens, $0.19 per unit (via GoodRx)
  • The good: It is “smoother” and longer acting than Levemir or NPH. Covered by most insurance.
  • The bad: It stings! Rarely, some people may have a blood glucose drop 2-6 hours after injection which can cause overnight lows.

Ultra Long Acting Insulins — Insulin glargine U-300

Insulin glargine U-300 (Toujeo) is a fairly new basal insulin approved in 2015. It has a longer action than Lantus and is 3x more concentrated. Insulin glargine U-300 usually requires a higher dose than would be needed for other basal insulins.

Action Profile

  • TIme to start working: ~6 hours
  • Time to max effect: Requires several doses; 4-5 days
  • Time till it wears off: ~36 hours

Good and Bad

  • Cost: ~$310 for 3 pens, $0.23 per unit (via GoodRx)
  • The good: Great for those who have very high basal insulin doses due to the smaller volume for each dose. Lasts even longer than Lantus and Basglar.
  • The bad: Expensive and still not covered by all insurances. It stings! It’s not good for people who experience changes in basal doses because it takes a while for dose changes to stabilize.

Ultra Long Acting Insulins — Insulin degludec U-100 and U-200

Insulin Degludec U-100 and U-200 are also fairly new to the market. Insulin degludec usually requires a lower dose than would be needed for other basal insulins.

Action Profile

  • TIme to start working: up to 12 hours
  • Time to max effect: Requires several doses; 3-5 days
  • Time till it wears off: > 42 hours

Good and Bad

  • Cost: ~$530 to $630 for 3-5 pens, $0.35 per unit (via GoodRx)
  • The good: No sting! Has a long expiration date, good for 56 days at room temperature or after 1st use. The effect is more “smooth” and lasts longer than any other basal insulin on the market. More flexibility with regard to the timing of injections day-to-day.
  • The bad: Expensive and still not covered by all insurances. It’s not good for people who experience changes in basal doses because it takes a while for dose changes to stabilize.

Other Insulins with Long action

Insulin R U-500

Insulin R U-500 is considered specialty insulin for patients who have a very high daily insulin need. It is 5 times more concentrated than traditional insulins and has characteristics of short-acting and intermediate insulin combined. Many patients on this insulin use only U-500 and inject it 2-3 times each day.

Cost: ~$600 for 2 pens, $0.20 per unit (via GoodRx)

Insulin protamine

Insulin protamine (the long-acting component of Humalog 75/25 and Novolog 70/30)

Insulin lispro protamine and insulin aspart protamine are only available as combo products. They are similar to Humulin 70/30 and Novolin 70/30 in the sense that they all have both a shorter acting and longer acting component. The newer and more expensive insulin protamine mixes kick in a little faster and last a little longer than their older cousins.

Cost: ~$340 to 580 for 5 pens, $0.23 to $0.39 per unit (via GoodRx)

Final Thoughts

Basal insulins are a critical part of management for most insulin-dependent people. Choosing the best basal insulin for an individual can come down to many factors. While most of us are very focused on cost and insurance coverage, we should also think about the differences in the time action profiles, ease of use, and accessibility.

Brad is a clinical pharmacy specialist working in a hospital setting. He has a professional focus on diabetes management, spending a portion of each day educating and caring for people with diabetes. Brad is also T1Dad to an amazing 3rd grader.

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