Humulin I (Isofano) (Insulin Human (Rdna))

Humulin I (Isofano) is indicated for the treatment of diabetes mellitus, providing basal insulin coverage to control fasting and between‑meal glucose concentrations.

• Type 1 diabetes mellitus requiring basal insulin supplementation.
• Type 2 diabetes mellitus when oral agents are insufficient for glycemic control.
• Adjunct therapy during pregnancy or lactation under medical supervision, if deemed appropriate.
• Management of hyperglycemia in patients undergoing surgery or acute illness.
• Replacement therapy for individuals with insulin deficiency due to pancreatic disease.
• Use as part of a basal‑bolus insulin regimen combined with rapid‑acting insulin analogues for intensive glucose management.
• Adjustment of dose may be required in patients with renal or hepatic impairment to avoid hypoglycemia.

• Humulin I (Isofano) contains recombinant human insulin that binds to insulin receptors on muscle, adipose and hepatic cells. Receptor activation triggers autophosphorylation and downstream signaling through the PI3‑kinase/Akt pathway, promoting translocation of GLUT‑4 transporters to the cell surface. This increases glucose uptake in peripheral tissues and suppresses hepatic gluconeogenesis, thereby lowering circulating blood glucose concentrations. The effect persists for several hours, providing basal insulin activity between meals and overnight.

Adverse reactions to Humulin I (Isofano) are generally related to its insulin activity and formulation components.

Common

• Mild hypoglycemia, characterized by shakiness, sweating, or hunger.
• Injection site reactions such as redness, swelling, or itching.
• Lipodystrophy presenting as localized thickening or loss of subcutaneous fat.
• Transient weight gain due to fluid retention.
• Nausea or mild gastrointestinal discomfort.
• Headache or dizziness, especially during rapid glucose changes.

Serious

• Severe hypoglycemia with loss of consciousness, seizures, or coma.
• Allergic reactions including urticaria, angioedema, or anaphylaxis.
• Persistent hyperglycemia indicating possible insulin resistance or dosing error.
• Edema or heart failure exacerbation in patients with pre‑existing cardiac disease.

When prescribing Humulin I (Isofano), clinicians should evaluate patient-specific factors and monitor for conditions that may alter insulin requirements or increase risk of adverse events.

• Assess renal and hepatic function, as impairment may prolong insulin action.
• Review history of hypoglycemia unawareness and adjust dosing accordingly.
• Consider pregnancy, lactation, and pediatric status before initiating therapy.
• Monitor weight and signs of fluid retention during long‑term use.
• Educate patients on proper injection technique to avoid lipodystrophy.
• Adjust dose during periods of illness, surgery, or changes in physical activity.

Humulin I (Isofano) may interact with other agents that affect blood glucose levels or insulin pharmacokinetics.

Avoid

• Concurrent use of other rapid‑acting insulin analogues without dose adjustment.
• High‑dose sulfonylureas that markedly increase hypoglycemia risk.
• Beta‑blockers that mask hypoglycemia symptoms.
• Alpha‑glucosidase inhibitors that may cause gastrointestinal upset and affect insulin absorption.

Use with caution

• Oral antihyperglycemics such as metformin, which may require dose titration.
• Corticosteroids that can raise glucose and may necessitate higher insulin doses.
• Diuretics, especially thiazides, that can affect electrolyte balance and glucose control.
• ACE inhibitors or ARBs, which can alter renal function and thus insulin clearance.