Humulin R (Insulin Human (Rdna))

Humulin R is prescribed to manage hyperglycemia in patients with diabetes when rapid insulin action is required.

• Mealtime (prandial) insulin for type 1 diabetes mellitus.
• Mealtime insulin for type 2 diabetes mellitus, often combined with basal insulin.
• Correction of elevated blood glucose during illness, stress, or steroid therapy.
• Use in insulin pump therapy where a rapid‑acting insulin is needed.
• Pediatric use under medical supervision for both type 1 and type 2 diabetes.

• Humulin R contains recombinant human insulin that binds to insulin receptors on muscle, adipose and hepatic cells. Receptor activation triggers autophosphorylation of the β‑subunit, initiating the PI3‑K/Akt signaling cascade, which promotes translocation of GLUT‑4 transporters to the cell surface, increasing glucose uptake. In the liver, insulin suppresses gluconeogenesis and glycogenolysis, reducing endogenous glucose production.

Adverse reactions to Humulin R vary in frequency and severity.

Common

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

Serious

• Severe hypoglycemia with loss of consciousness.
• Allergic reactions such as urticaria, angioedema, or anaphylaxis.
• Edema or exacerbation of heart failure.
• Hypokalemia.

Before initiating Humulin R, clinicians should evaluate several safety considerations to minimize risk.

• Assess renal and hepatic function, as impairment may alter insulin clearance.
• Review history of hypoglycemia unawareness or recurrent severe episodes.
• Adjust doses when patients are pregnant, lactating, or planning pregnancy.
• Monitor for signs of cardiovascular disease, especially in patients with edema or heart failure.
• Educate patients on proper injection technique and rotation to prevent lipohypertrophy.
• Consider potential interactions with other antidiabetic agents.

Humulin R can interact with other medicines that affect blood glucose or insulin metabolism.

Avoid

• Concurrent use of other rapid‑acting insulins without dose adjustment.
• Beta‑blockers that may mask hypoglycemia symptoms.
• MAO‑inhibitors that can potentiate insulin’s glucose‑lowering effect.
• High‑dose corticosteroids that increase insulin resistance.

Use with caution

• Oral antidiabetic agents such as sulfonylureas or meglitinides, which may increase hypoglycemia risk.
• Thiazide diuretics that can raise blood glucose levels.
• Alcohol consumption, which can cause delayed hypoglycemia.