powered by MyTherapy

Insulin Glargine (Lantus): 10 Answers Inc. Dosage, Interactions, and Injections

Answers to the most common questions about insulin glargine

Insulin glargine is a synthetic form of long-acting insulin, sold under the brand name Lantus, that is used to treat type I and type II diabetes. Injected once a day, the goal of treatment with insulin glargine is to make up for the insulin not being properly produced due to diabetes. Approved by the FDA in April 2000, Insulin Glargine has since become one of the top 50 most prescribed drugs worldwide. In the US alone, more than 24 million patients are currently taking the drug.

The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.

  1. How does insulin glargine work?
  2. What is a safe dosage of insulin glargine?
  3. Are there any interactions with insulin glargine?
  4. What warnings should I be aware of when taking insulin glargine?
  5. How much does insulin glargine cost?
  6. How do you inject insulin glargine?
  7. Where can I find the insulin glargine package insert?
  8. What is the generic name of insulin glargine?
  9. What are the side effects of insulin glargine?
  10. Can you mix glargine and regular insulin?

1. How does insulin glargine work?

The way insulin glargine works within the body is the same as the insulin that a healthy person produces normally. The main difference is that since insulin glargine is made to compensate for the insulin not being produced, it lasts much longer than the natural version. This helps people with type I or II diabetes to maintain healthy blood sugar levels throughout the day. By injecting insulin glargine once daily, patients with diabetes can ensure blood sugar enters the cells to be used for energy and prevent the liver from producing additional sugar.

2. What is a safe dosage of insulin glargine?

The proper dosage of insulin glargine will vary between patients. You must always follow your doctor’s instructions or the directions on the label. The following information contains typical doses of insulin glargine. For type I diabetes, there is typically an initial dose of one-third the total insulin requirement injected once a day. It is also accompanied by a short acting premeal insulin to meet total requirements for the day. Due to the complex nature of dosing insulin, you must speak with your doctor if you’re not sure what dosage you need.

3. Are there any interactions with insulin glargine?

There is a long list of drugs, supplements, and vitamins that may interact with insulin glargine or affect the way it works. To ensure you avoid any negative interactions, you must speak with your doctor about anything you’re taking before beginning treatment.

Among the most important interactions to be aware of are drugs that reduce blood sugar, as taking them with insulin glargine may lead to dangerously low blood sugar. You should also be sure to mention any drugs you’re taking such as drugs for hypertension or antipsychotics as they could interact with insulin glargine.

4. What warnings should I be aware of when taking insulin glargine?

There are a handful of warnings that come along with taking insulin glargine. Some of them are listed below. You should still speak to your doctor to find out if any warnings pertain directly to you before taking the drug.

  • Low blood sugar – Sometimes patients taking insulin glargine can experience low blood sugar. It’s important to watch out for symptoms of low blood sugar (such as tingling, dizziness, blurred vision, increased heart rate, and unsteady walking)
  • Warnings for specific patient groups – Pregnant women, women who are breastfeeding, seniors, and children may respond differently to insulin glargine. Be sure to speak to your doctor about this warning specifically if you’re in one of these groups.
  • Low potassium warning – Any insulin product may lead to reduced potassium levels, which can cause irregular heartbeats. To avoid this, your doctor will likely test your potassium levels before beginning treatment.
  • Infection warning – This warning applies to every injectable but is always important. You should never share or reuse needles, as there is a risk of transmission of blood borne pathogens.
  • Disease-specific warnings – People with liver or kidney disease will often need to take lower doses of the medication as your kidney and liver are supposed to be active in breaking down insulin glargine. If they are unable to carry out this function a lower dosage is necessary.

5. How much does insulin glargine cost?

One of the most common questions regarding insulin is about the cost. While it’s impossible to say what it will cost you individually, as that will depend on your location and insurance, we can provide a cash estimate. The average cash price of Lantus, the name brand of insulin glargine, is about $300/month.

6. How do you inject insulin glargine?

Many patients taking insulin glargine will administer self-injections, due to the frequency at which they must take the drug. However, you mustn’t begin self-injections before speaking with your doctor and knowing how to do it properly. If you’ve already spoken with your doctor and it’s been determined that you should proceed with self-injections, the following video from SingHealth may provide helpful information as a reminder for how to perform insulin injections in general.

Disclaimer: This is a third-party video and may contain advertisements

7. Where can I find the insulin glargine package insert?

You can find the full package insert provided by the FDA here in PDF form.

8. What is the generic name of insulin glargine?

At the time of writing, there is still no generic form of insulin glargine. However, it is sold under the brand names Basaglar and Toujeo as well.

9. What are the side effects of insulin glargine?

Insulin glargine may potentially cause side effects ranging from mild to severe. The list below includes some of the most common side effects but is not a complete list. Mild side effects may go away after a few days or weeks of consistent medication-taking, but if they persist or worsen you should speak with your doctor.

Common side effects:

Serious side effects:

  • Hypokalemia (low potassium) – symptoms include weakness, fatigue, cramps, and abnormal heartbeats
  • Hypoglycemia (low blood sugar)
    If you experience any of these serious side effects, you should speak with your doctor or seek immediate medical attention if it is an emergency.

In some rare cases, patients can experience allergic reactions. Seek emergency medical care if you experience any of the following symptoms after taking insulin glargine.

  • Skin rash
  • Wheezing
  • Tightness in the throat or chest
  • Difficulty talking or breathing
  • Swelling of the face, lips, tongue, or throat

10. Can you mix glargine and regular insulin?

You should not mix glargine with any other type of insulin. It can change how effective the medicine is. Switching between insulins should only be done under medical supervision.


The content on this page is provided for informational purposes only. If you have any questions or concerns about your treatment, you should talk to your doctor, pharmacist, or healthcare professional. This is particularly important if you are taking multiple medications or have any existing medical conditions.

Manage Your Treatment With MyTherapy

  • Well-being and symptom tracker
  • Reliable medication reminders
  • Health report for a detailed overview

Download MyTherapy for iPhone
Download MyTherapy for Android

Download MyTherapy for free Download MyTherapy for free