Insulin Isophane, also known as Neutral Protamine Hagedorn (NPH) insulin, is an intermediate-acting insulin suspension. It is a cloudy or milky suspension of insulin complexed with protamine and zinc, which delays its absorption and prolongs its duration of action. It is used to provide basal insulin coverage in the management of diabetes mellitus.
Adult: Highly individualized. Typical starting dose in insulin-naïve Type 2 DM: 0.1-0.2 IU/kg/day, given once or twice daily. Often administered at bedtime or in the morning. Dose is titrated based on fasting blood glucose (FBG) targets.
Note: For subcutaneous injection only. Inject into abdomen, thigh, buttocks, or upper arm. Rotate sites. Before use, gently roll pen/vial between palms until suspension is uniformly cloudy. Do not shake vigorously. Use a U-100 insulin syringe or pen device. Administer once or twice daily as prescribed.
Insulin Isophane binds to the insulin receptor (a tyrosine kinase receptor) on target cells (primarily liver, muscle, and adipose tissue). This binding activates the receptor's intrinsic tyrosine kinase activity, initiating a cascade of intracellular signaling events (PI3K-Akt and MAPK pathways). The primary metabolic effects are the facilitation of cellular glucose uptake, inhibition of hepatic glucose production (gluconeogenesis and glycogenolysis), promotion of glycogen, lipid, and protein synthesis, and inhibition of lipolysis and proteolysis.
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 mandatory.
Driving: Caution advised. Patients must be aware of hypoglycemia symptoms. Blood glucose should be checked before and during long drives.
| Oral Hypoglycemic Agents (Sulfonylureas, Meglitinides) | Additive hypoglycemic effect, increased risk of hypoglycemia. | Major |
| Corticosteroids (e.g., Prednisone) | Antagonizes insulin effect, causing hyperglycemia and increased insulin requirement. | Major |
| Beta-blockers (e.g., Propranolol) | May mask tachycardia signs of hypoglycemia and impair counter-regulatory response. | Moderate |
| Thiazide Diuretics | May cause hyperglycemia, increasing insulin needs. | Moderate |
| Alcohol | Potentiates hypoglycemic effect and can impair gluconeogenesis, risk of delayed hypoglycemia. | Major |
| ACE Inhibitors, MAOIs, Salicylates | May potentiate hypoglycemic effect. | Moderate |
Same composition (Insulin Isophane (100IU/ml)), different brands: