Diabetes Dogs & Cats

Insulin glargine (Lantus) for dogs and cats

A long-acting human insulin used mostly in diabetic cats. [1]

Last reviewed: October 2026 · 4 sources · see sources

Quick answerInsulin glargine (Lantus) (insulin glargine) is a prescription medicine for dogs and cats. It releases slowly from under the skin to keep blood sugar steadier. The most common side effects: skin lumps at injection sites.

Key facts

Generic nameInsulin glargine
Common brand namesLantus, Basaglar
Used inDogs & Cats
TypeDiabetes
Prescription?Prescription
Typical US price$30–$150 a month [2]

What it's used for

A long-acting human insulin used mostly in diabetic cats. [1]

How it works

It releases slowly from under the skin to keep blood sugar steadier. [1]

Side effects and cautions

Common side effects: Skin lumps at injection sites. Low blood sugar is the main danger. [1]

Use with care: Not for pets that aren't eating or have low blood sugar. Ask your vet before changing insulin or syringe type. [1]

Call your vet right away if your pet has trouble breathing, facial swelling, hives, collapse, or any side effect that is severe or getting worse.

About dosingDosing is your vet's call. We don't list doses because the right amount depends on your pet's weight, age, health and other medicines. Don't change a dose or stop a medicine without asking your vet, and never give a pet medicine meant for people unless your vet tells you to [4].

What it costs

Prices come from public owner-bill reports and vary by clinic, pharmacy, pet size and dose.

Insulin glargine (Lantus) FAQ

What is Insulin glargine (Lantus) used for in dogs and cats?

A long-acting human insulin used mostly in diabetic cats.

What are the side effects of Insulin glargine (Lantus)?

Skin lumps at injection sites. Low blood sugar is the main danger.

Does Insulin glargine (Lantus) need a prescription?

Yes. It needs a prescription from a veterinarian.

How much Insulin glargine (Lantus) should I give my pet?

Only your veterinarian can tell you. The right dose depends on your pet's weight, health and other medicines, so we don't list doses. Never give a pet a medicine prescribed for a person or another animal without asking your vet.

Related medications

Related cost guides

This page is general information for pet owners, not veterinary advice. Talk to your vet about your own pet.

Sources (4) — tap to show
  1. VCA Animal Hospitals – Insulin glargine (veterinary drug handout)
  2. PetRules USA – Cost of managing diabetes in dogs and cats
  3. RealVetCost – Feline diabetes treatment cost
  4. FDA – Frequently asked questions about animal drugs