Overview
Insulin glargine is a long-acting basal insulin analog used to control hyperglycemia in diabetes mellitus. It has a prolonged duration of action (up to 24 hours) with no pronounced peak, providing consistent basal insulin coverage. It is typically administered once daily at the same time each day.
Mechanism of Action
Insulin glargine binds to insulin receptors on target cells (muscle, fat, liver), facilitating glucose uptake, inhibiting hepatic glucose production, and promoting protein synthesis and lipogenesis. Its modified structure (substitution of asparagine with glycine at A21 and addition of two arginines to B-chain) results in precipitation at neutral pH after subcutaneous injection, leading to slow, sustained absorption.
Indications
- Type 1 diabetes mellitus
- Type 2 diabetes mellitus
Dosage
Individualized based on glycemic control. Typically administered subcutaneously once daily at the same time, usually at bedtime. Dose adjustments may be needed based on blood glucose monitoring, meal patterns, and physical activity. Do not dilute or mix with other insulins.
Contraindications
- Hypersensitivity to insulin glargine or any component
- During episodes of hypoglycemia
Side Effects
- Hypoglycemia
- Injection site reactions (pain, redness, swelling)
- Lipodystrophy
- Allergic reactions
- Peripheral edema
- Weight gain
- Hypokalemia
Interactions
- Drugs that may increase hypoglycemia risk: oral antidiabetics, ACE inhibitors, fibrates, fluoxetine, MAO inhibitors, pentoxifylline, propoxyphene, salicylates, sulfonamide antibiotics
- Drugs that may decrease hypoglycemic effect: corticosteroids, danazol, diuretics, sympathomimetics (e.g., albuterol, epinephrine), isoniazid, phenothiazines, somatropin, thyroid hormones, estrogens, progestins
- Beta-blockers, clonidine, lithium salts, and alcohol may potentiate or weaken glucose-lowering effects