Introduction
Lantus (insulin glargine) is a long-acting basal insulin analog used in the management of diabetes mellitus. Developed by Sanofi, it was first approved by the FDA in 2000 and has since become a cornerstone therapy for both type 1 and type 2 diabetes. Lantus provides sustained, peakless basal insulin coverage that mimics physiological basal insulin secretion, offering improved glycemic control with reduced hypoglycemia risk compared to older intermediate-acting insulins.
Mechanism of Action
Insulin glargine functions as a recombinant human insulin analog with modified molecular structure. The substitution of asparagine with glycine at position A21 and the addition of two arginine molecules to the B-chain terminus alter the isoelectric point from pH 5.4 to 6.7. This modification makes the molecule less soluble at physiological pH, resulting in the formation of microprecipitates upon subcutaneous injection. These microprecipitates slowly dissolve, releasing small amounts of insulin glargine into the systemic circulation, providing a prolonged, relatively constant basal insulin supply over approximately 24 hours.
Lantus binds to insulin receptors on target cells, facilitating glucose uptake by stimulating translocation of glucose transporter type 4 (GLUT4) to cell membranes. It promotes carbohydrate metabolism, inhibits hepatic glucose production, and regulates protein and lipid metabolism through the same mechanisms as endogenous insulin.
Indications
- Treatment of type 1 diabetes mellitus in adults and pediatric patients aged 6 years and older
- Treatment of type 2 diabetes mellitus in adults
- Used as basal insulin in combination with prandial insulin or other antihyperglycemic agents
Dosage and Administration
Initial Dosing:- Type 1 diabetes: Approximately one-third to one-half of total daily insulin requirements as basal insulin
- Type 2 diabetes: Starting dose typically 0.2 units/kg or 10 units once daily
- Administer subcutaneously once daily at the same time each day
- Rotate injection sites within the same region (abdomen, thigh, or upper arm)
- Do not dilute or mix with other insulins or solutions
- Available in 100 units/mL concentration in vials, prefilled pens (Lantus SoloStar), and cartridges
- Renal impairment: Requires careful dose titration and monitoring
- Hepatic impairment: Increased risk of hypoglycemia; requires dose reduction and close monitoring
- Geriatric patients: Initial dose reduction may be necessary due to increased hypoglycemia risk
Pharmacokinetics
Absorption: Slow, constant release from subcutaneous tissue with onset of action within 1-2 hours Distribution: Distributed throughout extracellular fluid; protein binding approximately 98% Metabolism: Metabolized in liver, kidney, muscle, and adipose tissue to active and inactive metabolites Elimination: Half-life approximately 12 hours; duration of action up to 24 hours or longer Time to peak effect: No pronounced peak; steady concentration maintained throughout dosing intervalContraindications
- Hypersensitivity to insulin glargine or any component of the formulation
- During episodes of hypoglycemia
- Hypersensitivity reactions including anaphylaxis
Warnings and Precautions
Hypoglycemia: Most common adverse effect; risk increased with changes in meal patterns, exercise, concomitant glucose-lowering medications Hypokalemia: Insulin preparations may cause potassium shifts into intracellular space Lipodystrophy: May occur at injection sites; rotate injection sites to reduce risk Weight gain: Can occur with insulin therapy Fluid retention: May cause edema, particularly with rapid improvement in glycemic control Visual disturbances: May occur with rapid glycemic changes Allergic reactions: Both local and systemic reactions possible Medication errors: Do not interchange with other insulins; clearly distinguish from rapid-acting insulinsDrug Interactions
Drugs that may increase hypoglycemia risk:- Oral antidiabetic agents
- ACE inhibitors
- Disopyramide
- Fluoxetine
- Fibrates
- MAO inhibitors
- Pentoxifylline
- Propoxyphene
- Salicylates
- Somatostatin analogs
- Sulfonamide antibiotics
- Corticosteroids
- Danazol
- Diuretics
- Estrogens
- Glucagon
- Isoniazid
- Niacin
- Phenothiazines
- Protease inhibitors
- Somatropin
- Sympathomimetic agents
- Thyroid hormones
Adverse Effects
Common (≥1%):- Hypoglycemia
- Injection site reactions (redness, pain, itching, swelling)
- Weight gain
- Allergic reactions
- Lipodystrophy
- Peripheral edema
- Severe hypoglycemia
- Hypokalemia
- Anaphylaxis
- Sodium retention and heart failure in susceptible patients
Monitoring Parameters
- Blood glucose levels (fasting and postprandial)
- HbA1c every 3-6 months
- Hypoglycemia symptoms and frequency
- Injection sites for lipodystrophy or reactions
- Weight changes
- Renal and hepatic function in patients with impairment
- Potassium levels in patients at risk for hypokalemia
- Signs of fluid retention in patients with cardiac disease
Patient Education
- Administer once daily at the same time each day
- Do not mix or dilute Lantus with other insulins
- Rotate injection sites within the same body region
- Recognize and treat hypoglycemia symptoms (sweating, dizziness, tremor, hunger)
- Never share insulin pens or needles
- Proper storage: refrigerate unopened vials/pens; may be stored at room temperature for up to 28 days after first use
- Regular self-monitoring of blood glucose
- Importance of consistent meal patterns and exercise
- Carry glucose source for hypoglycemia treatment
- Inform healthcare providers about all medications
- Wear medical identification indicating diabetes diagnosis
References
1. American Diabetes Association. Standards of Medical Care in Diabetes—2023. Diabetes Care. 2023;46(Suppl 1):S1-S291. 2. Lantus [package insert]. Bridgewater, NJ: Sanofi-Aventis U.S. LLC; 2021. 3. Home PD. The pharmacokinetics and pharmacodynamics of rapid-acting insulin analogues and their clinical consequences. Diabetes Obes Metab. 2012;14(9):780-788. 4. Rosenstock J, et al. Basal insulin therapy in type 2 diabetes: 28-week comparison of insulin glargine (HOE 901) and NPH insulin. Diabetes Care. 2001;24(4):631-636. 5. Riddle MC, et al. The treat-to-target trial: randomized addition of glargine or human NPH insulin to oral therapy of type 2 diabetic patients. Diabetes Care. 2003;26(11):3080-3086. 6. Bolli GB, et al. Efficacy and safety of insulin glargine given in the evening with a meal compared to morning administration in type 2 diabetes mellitus: A randomized controlled trial. Diabetes Obes Metab. 2015;17(10):959-967.