Humulin I (Isophane) (Insulin Human (Rdna))

Humulin I (Isophane) is indicated for the management of blood glucose in adults with diabetes.

• Used in type 1 diabetes mellitus as part of a basal insulin regimen.
• Used in type 2 diabetes mellitus when basal insulin is required.
• Adjunct to oral antidiabetic agents in patients whose glucose is inadequately controlled.
• Combined with rapid‑acting insulin analogues for basal‑bolus therapy.
• May be employed during pregnancy when benefits outweigh risks, under medical supervision.

• Humulin I (Isophane) consists of recombinant human insulin that forms microprecipitates after injection, creating a depot that releases insulin slowly. The insulin molecules bind to insulin receptors on muscle and adipose cells, activating the receptor’s tyrosine kinase pathway. This promotes translocation of GLUT‑4 transporters, increasing glucose uptake, and suppresses hepatic gluconeogenesis, thereby lowering circulating blood glucose levels. The prolonged action helps maintain basal insulin levels between meals and overnight.

Adverse reactions to Humulin I (Isophane) can vary in frequency and severity.

Common

• Mild hypoglycemia (low blood sugar).
• Injection site redness, swelling, or itching.
• Lipodystrophy at the injection site.
• Weight gain associated with improved glycemic control.

Serious

• Severe hypoglycemia with neurological symptoms.
• Allergic reactions such as urticaria, angioedema, or anaphylaxis.
• Edema or heart failure exacerbation.
• Hypersensitivity leading to bronchospasm.

When prescribing or using Humulin I (Isophane), clinicians should consider several precautionary measures to ensure safe therapy.

• Assess renal and hepatic function before initiation.
• Monitor blood glucose regularly to adjust dose and prevent hypoglycemia.
• Use caution in patients with cardiovascular disease or heart failure.
• Evaluate for signs of allergic reactions during the first weeks of therapy.
• Adjust dose during pregnancy, lactation, or in elderly patients.
• Avoid abrupt discontinuation without medical guidance.

Humulin I (Isophane) may interact with other medicines, affecting glucose control or insulin activity.

Avoid

• Concurrent use of other insulin products without dose adjustment.
• Beta‑blockers that mask hypoglycemia symptoms.
• MAO‑inhibitors that can potentiate insulin’s glucose‑lowering effect.

Use with caution

• Oral antidiabetic agents (e.g., sulfonylureas, meglitinides) that increase hypoglycemia risk.
• Corticosteroids, which may raise blood glucose and require higher insulin doses.
• Thyroid hormones, as hyperthyroidism can enhance insulin clearance.