Insulin Glargine

About Insulin Glargine

Insulin glargine is a long-acting human insulin analog used as background insulin; in type 1 diabetes it is paired with a short- or rapid-acting mealtime insulin. The labels approve it to improve blood sugar control in adults and children with diabetes: the pediatric studies enrolled children 6 to 15 with type 1 diabetes, Toujeo is labeled from age 6, and Basaglar covers children with type 1 diabetes only. It is not recommended for diabetic ketoacidosis. It is injected once a day at the same time. With Lantus, people with type 2 diabetes not yet on insulin start at 0.2 units per kg or up to 10 units once a day, and people with type 1 at about a third of their total daily insulin.

There is no boxed warning. It must not be used during an episode of low blood sugar or by anyone allergic to insulin glargine or an ingredient. Low blood sugar is the most common adverse reaction and can be severe, and any change of insulin product or injection method is made under close medical supervision. Mix-ups between insulin products have happened, so the label is checked before every injection, and pens, needles and syringes are never shared. Severe allergic reactions and low potassium can occur, and with pioglitazone or a similar drug it can cause fluid retention and heart failure. Unit for unit, Toujeo lowers blood sugar less than Lantus, so people switching from Lantus usually need a higher Toujeo dose, and switching from Toujeo to a 100 units per mL glargine starts at a lower dose.

Semglee (insulin glargine-yfgn) was approved in July 2021 as the first interchangeable biosimilar insulin and is also sold unbranded as insulin glargine-yfgn; Rezvoglar (insulin glargine-aglr) was licensed as interchangeable in November 2022. Langlara (insulin glargine-aldy), a pen approved in April 2026, was licensed as biosimilar to and interchangeable with the Lantus SoloStar pen. Basaglar, approved in 2015 under a drug application and licensed as a biologic since March 2020, is neither a biosimilar nor interchangeable with Lantus. Toujeo is also sold unbranded as Insulin Glargine U-300. Needles are not included with the pens, so pen needles are a separate item.

Taking Insulin Glargine

How to take it

Under the skin of the abdomen, thigh or upper arm once a day at the same time, rotating the spot within the same area to lower the risk of thickened skin or lumps. Never dilute it, mix it with another insulin, use it in a pump or inject it into a vein, and never draw Toujeo from its pen into a syringe.

If you miss a dose

Ask the prescriber ahead of time what to do if you forget a dose or accidentally take an extra one, and write the directions down.

Storage

Unopened in the refrigerator, never frozen. Once opened, 100 units per mL vials last 28 days in the refrigerator or at room temperature up to 86°F, and pens 28 days at room temperature only; Toujeo pens last 56 days at room temperature only.

Interactions to know about

Other diabetes medicines, ACE inhibitors, ARBs, fluoxetine and fibrates can raise the risk of low blood sugar; steroids, diuretics, estrogens and antipsychotics such as olanzapine can raise blood sugar; alcohol, beta blockers, clonidine and lithium can do either, and beta blockers and clonidine can hide a low.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Insulin Glargine differs from pharmacy to pharmacy

Each glargine product is priced by its own maker, and a quote is for the exact product, form and quantity dispensed. A prescription for Lantus, or for insulin glargine with substitution allowed, can be filled with an interchangeable biosimilar of the same form (vial or pen) where state law allows; Basaglar and Toujeo are not interchangeable with Lantus, so neither is swapped for it at the counter.

Vials and pens are separate products with separate quotes, and the box size, the daily dose and the in-use limit decide how long a fill lasts. Pen needles and syringes are quoted separately, and each pharmacy adds its own dispensing fee and markup.

Ways to pay less for Insulin Glargine without insurance

• Ask the prescriber to write for insulin glargine, or for Lantus with substitution allowed, so the pharmacy can quote an interchangeable biosimilar.
• If you can draw doses with a syringe, ask the prescriber whether vials would suit you, and ask for quotes on both.
• Manufacturers run patient programs whose terms change; ask the maker of your product whether one applies to someone paying cash.
• Ask for a quantity that matches your dose and the in-use limit, and never stretch or skip doses to make insulin last.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Insulin Glargine

1. 1.Which glargine product is this, and was it substituted for the one my prescriber named?
2. 2.How long can I use this pen or vial once it is opened?
3. 3.Which pen needles fit this pen, and do they need their own prescription here?
4. 4.If I switch between Toujeo and a 100 units per mL glargine, how will my dose change?

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