Comprehensive Guide to Insulin Glargine: Uses, Dosage, Side Effects, and More
What is Insulin Glargine?
Overview of Insulin Glargine
Generic Name: Insulin Glargine
Brand Name: Lantus, Toujeo, Basaglar, generics
Drug Group: Long-acting insulin (antidiabetic)
Commonly Used For
- Manage type 1 diabetes mellitus.
- Control type 2 diabetes mellitus.
- Provide basal insulin coverage.
Key Characteristics
Form: Prefilled pens or vials for subcutaneous injection (100 units/mL for Lantus/Basaglar, 300 units/mL for Toujeo) (detailed in Dosage section).
Mechanism: Forms a subcutaneous depot, releasing insulin slowly via pH-dependent precipitation.
Approval: FDA-approved (2000 for Lantus) and EMA-approved for diabetes management.
Indications and Uses of Insulin Glargine
Insulin Glargine is indicated for a range of diabetic conditions, leveraging its prolonged action to stabilize glucose levels:
Type 1 Diabetes Mellitus: Provides basal insulin to prevent hyperglycemia, per endocrinology guidelines, supported by clinical trials showing improved HbA1c by 0.5–1% over 6 months.
Type 2 Diabetes Mellitus: Controls fasting glucose in combination with oral agents or prandial insulin, recommended in diabetes management protocols with evidence of reduced nocturnal hypoglycemia.
Gestational Diabetes: Investigated off-label to manage hyperglycemia in pregnancy, improving maternal and fetal outcomes, with obstetrics-endocrinology data.
Latent Autoimmune Diabetes in Adults (LADA): Used off-label to delay beta-cell failure, with autoimmune diabetes research.
Cystic Fibrosis-Related Diabetes (CFRD): Explored off-label to address insulin deficiency, with pulmonology-endocrinology studies.
Steroid-Induced Hyperglycemia: Managed off-label in patients on long-term corticosteroids, with rheumatology-endocrinology evidence.
Critical Illness Hyperglycemia: Initiated off-label in ICU settings to stabilize glucose, with critical care data.
Post-Transplant Diabetes Mellitus: Applied off-label to control glucose post-organ transplant, with transplant medicine research.
Pediatric Diabetes: Used off-label in children <6 years with type 1 diabetes, with pediatric endocrinology studies.
Dosage of Insulin Glargine
Dosage for Adults
Type 1 Diabetes Mellitus:
Initial: 0.2–0.4 units/kg once daily at bedtime, adjusted based on pre-meal and fasting glucose (target 80–130 mg/dL).
Maintenance: 0.5–1.0 units/kg/day, often combined with prandial insulin.
Type 2 Diabetes Mellitus:
Initial: 0.1–0.2 units/kg once daily, titrated weekly by 2–4 units based on fasting glucose (target <130 mg/dL).
Maintenance: 0.3–0.6 units/kg/day, adjusted with oral antidiabetics.
Toujeo (300 units/mL):
Initial: One-third of total daily insulin dose, up to 0.2 units/kg, with careful titration.
Dosage for Children (≥6 years for Lantus/Basaglar, ≥1 year for Toujeo)
Type 1 Diabetes Mellitus:
Initial: 0.2–0.4 units/kg once daily, adjusted under pediatric endocrinology supervision.
Maintenance: 0.5–1.0 units/kg/day, monitored with SMBG.
Dosage for Pregnant Women
Pregnancy Category C: Use only if benefits outweigh risks; consult an obstetrician and endocrinologist, with fetal monitoring and dose adjustment based on glucose trends.
Dosage Adjustments
Renal Impairment: Reduce dose by 20–25% in severe cases (eGFR <30 mL/min); monitor glucose and renal function.
Hepatic Impairment:
Mild to moderate (Child-Pugh A or B): Use cautiously with reduced dose; severe (Child-Pugh C): Avoid due to limited data.
Concomitant Medications: Adjust if combined with hypoglycemic agents (e.g., metformin) or corticosteroids; monitor for interactions.
Elderly: Start with lower doses (e.g., 0.1 units/kg); assess for hypoglycemia risk.
Hypoglycemia: Reduce dose by 10–20% if severe episodes occur; individualize based on glucose logs.
Additional Considerations
Administer this active ingredient via subcutaneous injection into the abdomen, thigh, or upper arm, rotating sites to prevent lipodystrophy.
Inject at the same time daily, typically at bedtime, to maintain consistent basal levels.
Use U-100 (Lantus/Basaglar) or U-300 (Toujeo) pens/vials as prescribed, avoiding mixing with other insulins.
How to Use Insulin Glargine
Administration:
Subcutaneous: Pinch the skin, insert the needle at a 45–90° angle, and inject slowly; do not massage the site.
Use a new needle for each injection; do not shake the pen or vial.
Timing: Administer once daily, preferably at bedtime, with consistency to avoid glucose fluctuations.
Monitoring: Check blood glucose 1–2 times daily (fasting and pre-meal), watching for hypoglycemia (e.g., sweating, confusion) or hyperglycemia (e.g., thirst); report extremes immediately.
Additional Tips:
- Store unopened vials/pens at 2–8°C (36–46°F); opened pens/vials can be kept at room temperature (up to 30°C/86°F) for 28 days.
- Keep out of reach of children; dispose of used needles in a sharps container.
- Educate patients on glucose monitoring and recognition of hypo/hyperglycemic symptoms; provide a glucagon kit for emergencies.
- Rotate injection sites systematically to prevent hypertrophy; document site changes.
- Schedule regular HbA1c tests every 3 months to assess long-term control.
Contraindications for Insulin Glargine
Hypersensitivity: Patients with a known allergy to Insulin Glargine or its excipients (e.g., m-cresol).
Hypoglycemia: Contraindicated during active severe hypoglycemia until stabilized.
Diabetic Ketoacidosis (DKA): Avoid; use short-acting insulin for acute management.
Severe Hepatic Impairment: Contraindicated in Child-Pugh Class C due to altered metabolism.
Allergic Reactions: Avoid in patients with a history of severe insulin allergy (e.g., anaphylaxis).
Coma: Contraindicated in hyperglycemic hyperosmolar state (HHS) without initial stabilization.
Warnings & Precautions for Insulin Glargine
General Warnings
Hypoglycemia: Risk of severe low blood sugar; monitor glucose closely, especially during dose changes.
Hypokalemia: Risk of low potassium with prolonged use; check levels in at-risk patients.
Allergic Reactions: Risk of local or systemic reactions (e.g., rash, swelling); discontinue if severe.
Weight Gain: Common side effect; monitor in obese patients.
Edema: Risk of fluid retention; assess in heart failure patients.
Additional Warnings
Hypersensitivity: Rare anaphylaxis; stop if breathing difficulty occurs.
Lipodystrophy: Risk at injection sites; rotate sites to prevent.
Renal Impairment: Increased hypoglycemia risk; adjust dose and monitor.
Hepatic Impairment: Altered insulin clearance; use cautiously.
Retinopathy: Risk of progression with rapid glucose control; monitor vision.
Use in Specific Populations
Pregnancy: Category C; use with caution, monitoring fetal growth and maternal glucose.
Breastfeeding: Use caution; monitor infant for hypoglycemia.
Elderly: Higher hypoglycemia risk; start with lower doses.
Children: Safe for type 1 diabetes with supervision.
Renal/Hepatic Impairment: Adjust dose based on severity.
Additional Precautions
- Inform your doctor about kidney/liver disease, recent surgery, or hypoglycemia history before starting this medication.
- Carry a glucose source (e.g., candy) and ID for diabetes during therapy.
- Avoid alcohol to prevent unpredictable glucose shifts.
Overdose and Management of Insulin Glargine
Overdose Symptoms
Mild hypoglycemia (e.g., shakiness, hunger) or severe hypoglycemia (e.g., seizures, loss of consciousness).
Prolonged low glucose leading to neuroglycopenia or coma.
Sweating, tachycardia, or confusion as early signs.
Rare hypokalemia or cardiac arrhythmias with extreme doses.
Immediate Actions
Contact the Medical Team: Seek immediate medical help if severe symptoms occur.
Supportive Care: Administer oral glucose (15–20 g) for mild cases; use IV dextrose (10–25 g) or glucagon (1 mg IM) for severe cases.
Specific Treatment: No specific antidote; monitor glucose and potassium levels.
Monitor: Check blood glucose every 15–30 minutes until stable (target >70 mg/dL) for 4–6 hours.
Patient Education: Advise against doubling doses and to report accidental over-injection.
Additional Notes
- Overdose risk is linked to dosing errors; store securely and verify doses.
- Report persistent symptoms (e.g., prolonged confusion, weakness) promptly to prevent complications.
Side Effects of Insulin Glargine
Common Side Effects
- Hypoglycemia (10–20%, managed with glucose)
- Injection Site Reaction (5–15%, reduced with rotation)
- Weight Gain (5–10%, monitored with diet)
- Edema (2–7%, decreases with time)
- Lipohypertrophy (2–5%, prevented with site rotation)
These effects may subside with adaptation or dose adjustment.
Serious Side Effects
Seek immediate medical attention for:
- Metabolic: Severe hypoglycemia or diabetic ketoacidosis.
- Cardiac: Arrhythmias from hypokalemia.
- Allergic: Anaphylaxis or severe rash.
- Ocular: Worsening retinopathy.
- Neurological: Seizures or coma from neuroglycopenia.
Additional Notes
Regular monitoring with SMBG 2–4 times daily and HbA1c every 3 months is essential to detect hypoglycemia or poor control.
Patients with renal impairment should have glucose checked more frequently due to altered clearance.
Report any unusual symptoms (e.g., vision changes, persistent hunger) immediately to an endocrinologist.
Long-term use requires eye exams annually to monitor retinopathy progression.
Drug Interactions with Insulin Glargine
This active ingredient may interact with:
- Hypoglycemic Agents: Increases hypoglycemia risk (e.g., sulfonylureas); adjust dose.
- Corticosteroids: Reduces efficacy (e.g., prednisone); increase insulin if needed.
- Beta-Blockers: Masks hypoglycemia symptoms (e.g., propranolol); monitor closely.
- Alcohol: Potentiates hypoglycemia; avoid excess.
- ACE Inhibitors: May enhance hypoglycemic effect; monitor glucose.
Action: Provide your healthcare provider with a complete list of medications.
Patient Education or Lifestyle
Medication Adherence: Use this long-acting insulin as prescribed for diabetes, following the daily injection schedule.
Monitoring: Report hypoglycemia, hyperglycemia, or injection site issues immediately.
Lifestyle: Engage in regular exercise (with glucose checks); avoid skipping meals.
Diet: Follow a carbohydrate-consistent diet; consult a dietitian.
Emergency Awareness: Know signs of severe hypoglycemia; seek care if present.
Follow-Up: Schedule regular check-ups every 3–6 months to monitor HbA1c and complications.
Pharmacokinetics of Insulin Glargine
Absorption: Subcutaneous, peakless over 24 hours; bioavailability ~100%.
Distribution: Volume of distribution ~1.5 L/kg; binds to insulin receptors.
Metabolism: Hepatic and peripheral via insulin-degrading enzyme to inactive metabolites.
Excretion: Primarily renal (as metabolites); half-life ~12–20 hours.
Half-Life: 12–20 hours, with steady-state after 2–4 days.
Pharmacodynamics of Insulin Glargine
This drug exerts its effects by:
Providing a constant basal insulin level, suppressing hepatic glucose production.
Enhancing glucose uptake in skeletal muscle and fat via GLUT4 translocation.
Reducing fasting hyperglycemia over 24 hours of therapy.
Exhibiting dose-dependent risks of hypoglycemia and weight gain.
Storage of Insulin Glargine
Temperature: Store unopened vials/pens at 2–8°C (36–46°F); opened pens/vials at 15–30°C (59–86°F) for 28 days.
Protection: Keep in original packaging, away from direct heat and light.
Safety: Store in a secure location out of reach of children and pets due to overdose risk.
Disposal: Dispose of used needles in a sharps container per local regulations or consult a pharmacist.
Frequently Asked Questions (FAQs)
Q: What does Insulin Glargine treat?
A: This medication manages type 1 and type 2 diabetes.
Q: Can this active ingredient cause hypoglycemia?
A: Yes, hypoglycemia is common; carry glucose.
Q: Is Insulin Glargine safe for children?
A: Yes, for type 1 diabetes with supervision.
Q: How is this drug taken?
A: Via subcutaneous injection, once daily.
Q: How long is Insulin Glargine treatment?
A: Lifelong for type 1, variable for type 2.
Q: Can I use Insulin Glargine if pregnant?
A: Yes, with caution; consult a doctor.
Regulatory Information
This medication is approved by:
U.S. Food and Drug Administration (FDA): Approved in 2000 (Lantus) for diabetes management.
European Medicines Agency (EMA): Approved for type 1 and type 2 diabetes.
Other Agencies: Approved globally for diabetes control; consult local guidelines.
References
- U.S. Food and Drug Administration (FDA). (2023). Lantus (Insulin Glargine) Prescribing Information.
- Official FDA documentation detailing the drug’s approved uses, dosage, and safety.
- European Medicines Agency (EMA). (2023). Insulin Glargine Summary of Product Characteristics.
- EMA’s comprehensive information on the medication’s indications and precautions in Europe.
- National Institutes of Health (NIH). (2023). Insulin Glargine: MedlinePlus Drug Information.
- NIH resource providing detailed information on the drug’s uses, side effects, and precautions.
- World Health Organization (WHO). (2023). WHO Model List of Essential Medicines: Insulin Glargine.
- WHO’s inclusion of Insulin Glargine for diabetes.
- Diabetes Care. (2022). Insulin Glargine in Type 2 Diabetes.
- Peer-reviewed article on Insulin Glargine efficacy (note: access may require a subscription).
