Prescription medication · Long-Acting Insulin
insulin glargine
Also sold as Lantus, Basaglar, Toujeo. Basaglar is used to lower blood sugar in adults and children with type 1 diabetes.
Data updated 2026-05-15
- 236,147
- FDA reportsHeavily reported
- 11
- InteractionsSeveral interactions
- 57% less
- Generic vs brandBig savings
- In shortage
- FDA status
What the data shows
insulin glargine (Lantus) is a prescription Long-Acting Insulin, in the top 5% of tracked drugs by FAERS report volume (236,147 FDA reports), whose generic runs roughly half the brand price or less (57% less).
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
insulin glargine (Lantus) is a prescription Long-Acting Insulin. Basaglar is used to lower blood sugar in adults and children with type 1 diabetes.
Basaglar is a long-acting insulin that helps control blood sugar levels. It is used to treat type 1 and type 2 diabetes.
Verify with FDA → · CMS NADAC pricing →
Drug Shortage Alert
insulin glargine is currently listed as to be discontinued by the FDA. Affected manufacturer: Eli Lilly and Co..
View all drug shortages →Drug Pricing (NADAC)
Brand Price
$20.94/unit
Generic Price
$8.95/unit
Generic Savings
57%
Generic Available
Yes (0 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Basaglar is used to lower blood sugar in adults and children with type 1 diabetes.
Common side effects
Low blood sugar (hypoglycemia), Allergic reactions, Injection site reactions (redness, swelling, itching)
Key warnings
Never share your Basaglar pen with anyone else, even if you change the needle.
The sections below are summarized in plain English from insulin glargine's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Basaglar is a long-acting form of insulin. It works by replacing the insulin that your body does not make, or helping your body use insulin better. This helps to lower your blood sugar levels over a longer period.
How to Take It
Inject Basaglar under your skin once a day, at the same time each day. You can inject it at any time of day. Your doctor will tell you how much Basaglar to use based on your needs. Always check the insulin label before you inject it.
This is a plain-language summary of insulin glargine's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
Talk to your doctor if you are pregnant or plan to become pregnant. Poorly controlled diabetes during pregnancy can harm both the mother and the baby. Basaglar's effects during pregnancy are not well-studied.
This is a plain-language summary of insulin glargine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose of Basaglar, inject it as soon as you remember. Then, go back to your regular injection schedule.
This is a plain-language summary of insulin glargine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Keep unopened Basaglar pens in the refrigerator or at room temperature for up to 28 days. Opened pens should be stored at room temperature and used within 28 days.
Side Effects (from patient reports)
Based on 236,147 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for insulin glargine, by number of reports
- Increased blood sugar
Increased blood sugar
38,213 reports
- Decreased blood sugar 10,314
Decreased blood sugar
10,314 reports
- Taking the medicine at the wrong time 9,798
Taking the medicine at the wrong time
9,798 reports
- Feeling sick to your stomach 9,566
Feeling sick to your stomach
9,566 reports
- The medicine was stored incorrectly 8,531
The medicine was stored incorrectly
8,531 reports
- Vision problems 8,514
Vision problems
8,514 reports
- Low blood sugar 7,787
Low blood sugar
7,787 reports
- Loose stools 6,898
Loose stools
6,898 reports
- Feeling tired 6,760
Feeling tired
6,760 reports
- Wrong dose given 6,539
Wrong dose given
6,539 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for insulin glargine each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where insulin glargine sits
insulin glargine has more FDA adverse-event reports than 95% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is insulin glargine; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 236,147 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2001–2025.
Total Reports
236,147
Reports Mentioning Death
13,233
5.6% of reports — not proof of cause
Hospitalization Reports
62,916
Top Indication
Type 2 Diabetes Mellitus
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | BLOOD GLUCOSE INCREASED | 38,214 |
| 3 | BLOOD GLUCOSE DECREASED | 10,314 |
| 5 | INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION | 9,798 |
| 6 | NAUSEA | 9,568 |
| 7 | PRODUCT STORAGE ERROR | 8,531 |
| 8 | VISUAL IMPAIRMENT | 8,514 |
| 9 | HYPOGLYCAEMIA | 7,786 |
| 10 | DIARRHOEA | 6,900 |
| 11 | FATIGUE | 6,761 |
| 12 | INCORRECT DOSE ADMINISTERED | 6,540 |
| 13 | MALAISE | 6,531 |
| 14 | WEIGHT DECREASED | 6,309 |
| 15 | INJECTION SITE PAIN | 6,248 |
| 16 | DYSPNOEA | 6,216 |
| 17 | VOMITING | 6,030 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Never share your Basaglar pen with anyone else, even if you change the needle. Sharing pens can spread blood-borne diseases. Changes to your insulin plan can affect your blood sugar. Make sure a doctor supervises any changes and that you check your blood sugar often. Low blood sugar can be very dangerous and even life-threatening. Watch for symptoms and check your blood sugar often. Low potassium can also be life-threatening. Tell your doctor if you have heart problems or take certain diabetes medicines called thiazolidinediones, as this can lead to heart failure.
Known Drug Interactions
7 DRUG INTERACTIONS Table 6 includes clinically significant drug interactions with BASAGLAR Table 6: Clinically Significant Drug Interactions with BASAGLAR Drugs That May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analogs (e.g., octreotide), and sulfonamide antibiotics. Drugs that may increase the risk of hypoglycemia: antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents,...
Mechanism: Fluoxetine can increase the effect of insulin, which may cause your blood sugar to drop lower than expected.
What to do: Watch for signs of low blood sugar and talk to your doctor about adjusting your medication doses.
7 DRUG INTERACTIONS Table 6 includes clinically significant drug interactions with BASAGLAR Table 6: Clinically Significant Drug Interactions with BASAGLAR Drugs That May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analogs (e.g., octreotide), and sulfonamide antibiotics. Drugs that may increase the risk of hypoglycemia: antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents,...
Mechanism: Both medications are used to lower blood sugar, so using them at the same time increases the risk of hypoglycemia.
What to do: Your healthcare provider may need to adjust your insulin dose and you should monitor your blood sugar levels frequently.
7 DRUG INTERACTIONS Table 6 includes clinically significant drug interactions with BASAGLAR Table 6: Clinically Significant Drug Interactions with BASAGLAR Drugs That May Increase the Risk of Hypoglycemia Drugs: Antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents, disopyramide, fibrates, fluoxetine, monoamine oxidase inhibitors, pentoxifylline, pramlintide, salicylates, somatostatin analogs (e.g., octreotide), and sulfonamide antibiotics. Drugs that may increase the risk of hypoglycemia: antidiabetic agents, ACE inhibitors, angiotensin II receptor blocking agents,...
Mechanism: Octreotide can lower blood sugar levels, which adds to the effect of insulin and increases the risk of a dangerous drop.
What to do: Check your blood sugar levels often and consult your doctor about changing your insulin dose.
Drugs That May Decrease the Blood Glucose Lowering Effect of BASAGLAR Drugs: Atypical antipsychotics (e.g., olanzapine and clozapine), corticosteroids, danazol, diuretics, estrogens, glucagon, isoniazid, niacin, oral contraceptives, phenothiazines, progestogens (e.g., in oral contraceptives), protease inhibitors, somatropin, sympathomimetic agents (e.g., albuterol, epinephrine, terbutaline), and thyroid hormones Intervention: Dose increases and increased frequency of glucose monitoring may be required when BASAGLAR is co-administered with these drugs. Drugs that may decrease the blood...
Mechanism: Albuterol is a stimulant-like drug that can raise blood sugar, making your insulin work less effectively.
What to do: Check your blood sugar more often and talk to your doctor about whether your insulin dose needs to be increased.
Drugs That May Increase or Decrease the Blood Glucose Lowering Effect of BASAGLAR Drugs: Alcohol, beta-blockers, clonidine, and lithium salts. Drugs That May Blunt Signs and Symptoms of Hypoglycemia Drugs: beta-blockers, clonidine, guanethidine, and reserpine Intervention: Increased frequency of glucose monitoring may be required when BASAGLAR is co-administered with these drugs. Drugs that may increase or decrease the blood glucose lowering effect: alcohol, beta-blockers, clonidine, lithium salts, and pentamidine ( 7 ).
Mechanism: Clonidine can cause blood sugar to go up or down and can also hide the physical signs that your blood sugar is too low.
What to do: You should monitor your blood sugar more frequently since you may not notice the usual warning signs of a sugar drop.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
Can I mix Basaglar with other insulins?
Where should I inject Basaglar?
How often should I check my blood sugar?
What should I do if my blood sugar is too low?
What should I do if my blood sugar is too high?
Can I use Basaglar in an insulin pump?
What if I have vision problems?
How do I dispose of used Basaglar pens?
What if I travel?
What do I do if my Basaglar pen is damaged?
What are the common side effects of insulin glargine?
Does insulin glargine interact with other medications?
What drug class is insulin glargine?
Is there a generic version of insulin glargine?
Is insulin glargine safe during pregnancy?
Is insulin glargine currently in shortage?
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Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for insulin glargine
The FDA label for insulin glargine (sold under brand names such as Lantus, Basaglar, Toujeo) classifies it as a prescription-only medication in the Long-Acting Insulin class. Basaglar is used to lower blood sugar in adults and children with type 1 diabetes. Official labeling lists 11 commonly reported side effects, including Low blood sugar (hypoglycemia), Allergic reactions, Injection site reactions (redness, swelling, itching).
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 236,147 voluntary reports. The database also lists 11 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $8.95 versus $20.94 for the brand - a 57% generic savings.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC). Shortage status: FDA Drug Shortages Database.
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: December 11, 2025
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages