Humulin R

Humulin R is a short‑acting insulin human (rDNA) product supplied as a 100 U/mL solution for injection. It is a prescription‑only antidiabetic agent marketed in the European Union. The formulation is designed for subcutaneous, intravenous, or intramuscular administration to replace or supplement endogenous insulin in patients with diabetes mellitus. Humulin R provides onset of action within 15–30 minutes and a duration of 5–8 hours, making it suitable for mealtime glucose control.

Humulin R is indicated for the management of hyperglycaemia in several diabetic conditions where rapid insulin action is required.

- Type 1 diabetes mellitus, as part of a basal‑bolus insulin regimen to cover meals and correct post‑prandial spikes. - Type 2 diabetes mellitus, when oral agents are insufficient or when a rapid‑acting insulin is needed for mealtime control. - Gestational diabetes mellitus, under obstetric supervision, to achieve target maternal glucose levels. - Inpatient settings for surgical or critical‑care patients requiring intravenous insulin infusion to maintain tight glucose control. - Adjunct therapy during periods of stress, illness, or steroid use that increase insulin requirements.

Adverse reactions to Humulin R are reported across a range of frequencies and severities.

Common: - Hypoglycaemia, characterised by sweating, tremor, confusion or loss of consciousness. - Injection‑site reactions such as erythema, itching or mild swelling. - Weight gain associated with improved glycaemic control. - Edema or fluid retention, especially in patients with renal or cardiac impairment. - Local lipodystrophy or lipoatrophy at repeated injection sites.

Serious: - Severe hypoglycaemia requiring assistance, which can lead to seizures or coma. - Allergic reactions including urticaria, angio‑edema or anaphylaxis. - Persistent hyperglycaemia due to insulin resistance or dosing errors. - Lipodystrophy with significant tissue loss at injection sites. - Life‑threatening hypoglycaemic events in patients with impaired counter‑regulatory responses.

When prescribing or using Humulin R, clinicians and patients should consider several precautionary measures to minimise risk.

- Monitor blood glucose closely during initiation, dose adjustments, and periods of altered diet or activity. - Avoid use in patients with known hypersensitivity to human insulin or any excipients. - Adjust doses in renal or hepatic impairment, as insulin clearance may be reduced. - Pregnancy and lactation require careful glycaemic targets; consult obstetric guidance. - Educate patients on recognising and treating hypoglycaemia promptly. - Be aware of potential lipodystrophy with repeated injections at the same site. - Do not mix Humulin R with other insulin products unless specifically instructed.

Humulin R may interact with other medicines that affect glucose metabolism or insulin action, requiring dose modifications or monitoring.

Avoid: - Concurrent use of other rapid‑acting insulins or insulin analogues without dose adjustment, which can precipitate severe hypoglycaemia. - Beta‑blockers, which may mask hypoglycaemia symptoms and prolong recovery. - High‑dose corticosteroids, which increase insulin resistance and may necessitate higher insulin doses.

Use with caution: - Oral antidiabetic agents such as sulfonylureas or meglitinides, which also lower blood glucose. - MAO‑A inhibitors, which can potentiate insulin’s glucose‑lowering effect. - Thiazide diuretics, which may raise blood glucose and require closer monitoring. - Alcohol consumption, which can cause delayed hypoglycaemia, especially after a dose of insulin.