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Should My Insulin Dose Be Lower? Toujeo vs Lantus

by The GoodRx Pharmacist on August 18, 2015 at 9:00 am

Early in 2015 the FDA approved the first concentrated long-acting insulin known as Toujeo (insulin glargine), and it’s now available in pharmacies.

While Toujeo is the first of its kind, the key word is “concentrated.” It actually contains the same active ingredient (insulin glargine) as Lantus—which is currently the #1 prescribed insulin in the US.

To make things even more confusing: Toujeo comes in a 300 mg/mL dosage, while Lantus is 100 mg/mL. Knowing that Toujeo is concentrated, you might think that you can take a much smaller amount of Toujeo for a similar dose compared to Lantus. Believe it or not though, that isn’t the case.

Lantus and Toujeo doses are converted 1:1. This means that if you are injecting 50 units of Lantus, you can essentially be switched over to Toujeo and instructed to inject the exact same amount, 50 units. In reality, some dose adjustments can be expected (according to clinical trial data), but it isn’t a matter of converting to a three times smaller dose.

Surprisingly, patients who switch over to Toujeo are actually injecting higher doses compared to what they were using for Lantus. I see a lot of confusion around the different dosages, and a few common questions:

Is it normal for my dose of Toujeo to be more than my Lantus dose?

Yes. Although Toujeo has three times the concentration of insulin glargine, patients treated with Toujeo during clinical trials used more insulin than patients treated with Lantus in order to maintain the same level of blood sugar control. According to the manufacturer, Sanofi-Aventis, a higher dose can be expected with Toujeo and is completely normal.

Why would Sanofi-Aventis make Toujeo if Lantus is the most-prescribed insulin?

There is speculation that Sanofi-Aventis came up with Toujeo due to the upcoming patent expiration for Lantus, which should happen by mid-2016. Switching patients over to their new insulin product, Toujeo, would allow the company to continue making money once Lantus biosimilars are on the market.

How do Toujeo and Lantus compare in cost?

The most commonly filled monthly dose of Lantus is slightly more expensive than the most common dose of Toujeo. Both are fairly pricey if you don’t have insurance, but you can save more than $50 per month with a GoodRx discount.

Single carton of three 300 units/mL Toujeo pens*
Pharmacy Cash Price GoodRx Price
CVS $398 $350
Target $403 $352
Walmart $383 $352
Walgreens $413 $370


Single carton of five 100 units/mL Lantus pens*
Pharmacy Cash Price GoodRx Price
CVS $444 $389
Target $461 $390
Walmart $432 $399
Walgreens $396 $411


*Prices as of September 4, 2015.

Is Toujeo worth it?

If you are well-controlled on Lantus, in my opinion, switching to Toujeo may not be worth the overall hassle. When you switch to a different insulin product, it can take time for your body to get used to the new medication and you may need dose adjustments. This is part of what can lead to a potentially higher dose than what you were using with Lantus.

What kind of insulin is in Toujeo and Lantus?

Insulin glargine is a long-acting insulin, also known as basal insulin. Long-acting insulin lowers blood sugar levels slowly and evenly for up to 24 hours. This is the type of insulin you use to maintain your blood sugar between meals and at night.

Are there other long-acting insulins available besides Toujeo and Lantus?

Yes. Levemir is another example. Like Lantus, Levemir has a 100 mg/mL concentration and is available in a pre-filled pen and a vial.

Are there any differences in how you take Lantus and Toujeo?

Both Lantus and Toujeo are injected subcutaneously once daily, at the same time each day.

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