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

Humulin I is indicated for the management of diabetes mellitus when basal insulin coverage is required. It is commonly used as part of a comprehensive diabetes treatment plan that may include diet, exercise, and other medications.

• Type 1 diabetes mellitus requiring basal insulin support.
• Type 2 diabetes mellitus inadequately controlled with oral agents alone.
• Gestational diabetes mellitus when insulin therapy is indicated.
• Adjunct to rapid‑acting insulin for basal‑bolus regimens.
• Situations where a steady, intermediate‑acting insulin profile is preferred.

• Humulin I contains insulin human (isophane), which binds to insulin receptors on muscle, adipose, and hepatic cells. Receptor activation triggers intracellular signaling cascades that promote glucose uptake into peripheral tissues and suppress hepatic gluconeogenesis, resulting in a gradual and prolonged reduction of plasma glucose concentrations characteristic of intermediate‑acting insulin preparations.

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

Common

• Injection site redness, swelling, or itching.
• Mild hypoglycemia (low blood sugar).
• Weight gain.
• Lipodystrophy at the injection site.
• Transient headache.

Serious

• Severe hypoglycemia leading to loss of consciousness.
• Allergic reactions such as urticaria, angioedema, or anaphylaxis.
• Persistent hypoglycemia requiring medical intervention.
• Edema or heart failure exacerbation in susceptible patients.

When prescribing Humulin I, clinicians should consider several safety factors. Patients should be educated on proper injection technique and glucose monitoring.

• Adjust dose during periods of illness, stress, or changes in physical activity.
• Use caution in patients with renal or hepatic impairment.
• Monitor for signs of hypoglycemia, especially in the elderly or those with irregular meals.
• Evaluate cardiovascular status, as fluid retention may worsen heart failure.
• Pregnancy category B; benefits should outweigh potential risks.
• Store the suspension according to label instructions to maintain potency.

Humulin I may interact with other agents that affect blood glucose or insulin metabolism.

Avoid

• Concurrent use of other insulin products without dose adjustment.
• Beta‑blockers that mask hypoglycemia symptoms.
• High‑dose corticosteroids that increase glucose levels.

Use with caution

• Oral antidiabetic agents (e.g., sulfonylureas, meglitinides) that can potentiate hypoglycemia.
• Alcohol, which may cause unpredictable glucose fluctuations.
• Thyroid hormones, as hyperthyroidism can enhance insulin clearance.
• Certain diuretics that may affect electrolyte balance and glucose control.