Insulin Isophane, also known as Neutral Protamine Hagedorn (NPH) insulin, is an intermediate-acting insulin suspension. It is a cloudy, white suspension of human insulin complexed with protamine and zinc, which delays its absorption from the subcutaneous injection site. It is a cornerstone of basal insulin therapy in the management of diabetes mellitus, providing a longer duration of action compared to regular insulin. In the Indian context, it is widely used due to its cost-effectiveness and availability.
Adult: Highly individualized. Typical starting dose in insulin-naïve Type 2 DM: 0.1-0.2 units/kg body weight once daily (usually at bedtime) or divided twice daily. In Type 1 DM, it is part of a regimen; basal dose typically constitutes 40-50% of total daily insulin requirement. Dose adjustments are based on fasting blood glucose (FBG) levels.
Note: For subcutaneous use only. Administer into the abdominal wall, thigh, upper arm, or buttocks. Rotate injection sites within the same region. Before use, gently roll the vial/pen between palms 10 times and invert 10 times until a uniform, milky suspension is achieved. Do not shake vigorously. Inject immediately after mixing. Usually administered once or twice daily.
Insulin Isophane is a biosynthetic human insulin that regulates glucose metabolism. It binds to the alpha-subunit of the insulin receptor, a transmembrane tyrosine kinase receptor, on target cells (primarily liver, muscle, and adipose tissue). This binding triggers autophosphorylation of the receptor and activation of intracellular signaling cascades (IRS/PI3K/Akt pathway). The primary effects are increased cellular uptake of glucose (especially in muscle and fat), promotion of glycogenesis, inhibition of glycogenolysis and gluconeogenesis in the liver, and promotion of lipogenesis and protein synthesis.
Pregnancy: Pregnancy Category B (US FDA). Insulin is the drug of choice for glycemic control in pregnancy (both pre-existing and gestational diabetes). Requirements may decrease in first trimester and increase significantly in second/third trimesters. Close monitoring is essential. Human insulin is preferred over animal-source insulin.
Driving: Caution required. Patients must check blood glucose before driving and regularly during long journeys. Must be aware of and able to treat hypoglycemia symptoms. Should always carry a fast-acting carbohydrate source.
| Oral Hypoglycemic Agents (e.g., Sulfonylureas, Meglitinides) | Additive hypoglycemic effect, increased risk of hypoglycemia. | Major |
| Corticosteroids (e.g., Prednisolone, Dexamethasone) | Antagonize insulin effect, causing hyperglycemia and increased insulin requirement. | Major |
| Beta-blockers (e.g., Propranolol) | May mask tachycardia symptoms of hypoglycemia, impair recovery, and potentially prolong hypoglycemia. | Moderate |
| Thiazide Diuretics (e.g., Hydrochlorothiazide) | May cause hyperglycemia, increasing insulin requirement. | Moderate |
| ACE Inhibitors (e.g., Ramipril) | May enhance insulin sensitivity, increasing risk of hypoglycemia. | Moderate |
| Alcohol | Acute intake can potentiate hypoglycemia; chronic intake can cause hyperglycemia or hypoglycemia. | Major |
| MAO Inhibitors, Anabolic Steroids | Potentiate hypoglycemic effect. | Moderate |
Same composition (Insulin Isophane (100IU)), different brands: