Humulin I (Isophane) (Insulin Human)

Humulin I (Isophane) is indicated for the management of hyperglycemia in adults and children with diabetes mellitus, serving as a basal insulin component in multiple dosing regimens.

• Used as part of a basal‑bolus insulin regimen for type 1 diabetes mellitus.
• Combined with rapid‑acting insulin analogues to achieve tight glycemic control in type 2 diabetes mellitus.
• Prescribed for patients who require intermediate‑acting insulin to cover fasting and between‑meal glucose excursions.
• May be administered once or twice daily depending on individual therapeutic goals and lifestyle.
• Employed when a steady, prolonged insulin effect is preferred over short‑acting formulations.

• Humulin I contains recombinant human insulin that binds to insulin receptors on the surface of muscle, adipose and hepatic cells. Receptor activation triggers autophosphorylation and initiates intracellular signaling cascades, notably the phosphatidylinositol‑3‑kinase (PI3‑K) pathway, which promotes translocation of glucose transporter‑4 (GLUT‑4) to the cell membrane. This enhances glucose uptake and utilization while suppressing hepatic gluconeogenesis, thereby lowering circulating blood glucose concentrations.

Adverse reactions to Humulin I can vary in frequency and severity; they are typically categorized as common or serious.

Common

• Mild hypoglycemia, presenting as sweating, tremor, or hunger.
• Injection site reactions such as redness, swelling, or itching.
• Weight gain associated with improved glycemic control.
• Lipodystrophy, including localized lipoatrophy or lipohypertrophy at injection sites.

Serious

• Severe hypoglycemia leading to loss of consciousness or seizures.
• Allergic reactions ranging from urticaria to anaphylaxis.
• Edema or fluid retention causing peripheral swelling.
• Hypersensitivity‑induced bronchospasm or angioedema.

Clinicians should consider several precautionary measures when prescribing Humulin I to ensure safe and effective use.

• Assess renal and hepatic function, as impairment may alter insulin clearance.
• Adjust dose during periods of illness, stress, or changes in physical activity.
• Monitor blood glucose closely when initiating therapy or modifying the regimen.
• Avoid use in patients with known hypersensitivity to human insulin or any excipients.
• Educate patients on recognizing and treating hypoglycemia promptly.
• Pregnancy and lactation status should be evaluated, given limited safety data.

Humulin I may interact with other medications, affecting its glucose‑lowering effect or increasing the risk of adverse events.

Avoid

• Concurrent use of other insulin products or insulin secretagogues without dose adjustment.
• Beta‑blockers, which can mask hypoglycemia symptoms.
• High‑dose corticosteroids that raise blood glucose levels.

Use with caution

• Oral antidiabetic agents such as sulfonylureas, which may potentiate hypoglycemia.
• Thiazide diuretics, which can increase insulin resistance.
• Alcohol consumption, especially in excess, due to unpredictable glucose fluctuations.