HUMULIN R
Clinical safety rating: caution
Comprehensive clinical and safety monograph for HUMULIN R (HUMULIN R).
Human insulin is identical to endogenous insulin. It binds to insulin receptors on target cells, activates tyrosine kinase signaling, and promotes glucose uptake, glycogenesis, lipogenesis, and protein synthesis while inhibiting gluconeogenesis and glycogenolysis.
| Metabolism | Primarily degraded by insulin-degrading enzyme (IDE) in the liver, kidneys, and peripheral tissues. Renal and hepatic clearance contribute to elimination. |
| Excretion | Primarily renal (>90% as unchanged drug after degradation), with minor biliary/fecal elimination (<10%). |
| Half-life | Terminal elimination half-life: 0.5-1 hour (intravenous); prolonged in renal impairment (up to 3-4 hours). |
| Protein binding | 10-15% bound to plasma proteins (primarily albumin but low affinity). |
| Volume of Distribution | Approximately 0.15-0.25 L/kg; reflects distribution primarily into extracellular fluid. |
| Bioavailability | Subcutaneous: 55-80% (site and injection technique dependent); Intramuscular: 80-100%; Intravenous: 100%. |
| Onset of Action | Subcutaneous: 30-60 minutes; Intravenous: 10-30 minutes; Intramuscular: 15-30 minutes. |
| Duration of Action | Subcutaneous: 6-8 hours; Intravenous: 0.5-2 hours (dose-dependent); Intramuscular: 4-6 hours. |
Subcutaneous: 0.2-0.6 units/kg/day divided into 2-3 doses, individualized. Intravenous: Insulin infusion protocols for hyperglycemia.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment for insulin. GFR <30 mL/min: reduced insulin clearance may require dose reduction; monitor glucose closely. |
| Liver impairment | Hepatic impairment may reduce gluconeogenesis; insulin requirements may decrease. Child-Pugh A/B/C: monitor glucose, reduce dose as needed. |
| Pediatric use | Weight-based dosing: 0.5-1 unit/kg/day subcutaneously, divided into 2-4 doses; adjust based on blood glucose. |
| Geriatric use | Elderly: start with lower doses (e.g., 0.2 units/kg/day) due to renal decline and hypoglycemia risk; titrate slowly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for HUMULIN R (HUMULIN R).
| Breastfeeding | Insulin is excreted in breast milk in negligible amounts; M/P ratio unknown but clinically insignificant. Pumping immediately after administration may further reduce exposure. Compatible with breastfeeding. |
| Teratogenic Risk | Insulin (HUMULIN R) does not cross the placenta and is not teratogenic. Poor glycemic control during the first trimester is associated with increased risk of congenital anomalies; during the second and third trimesters, it is associated with macrosomia, polyhydramnios, preeclampsia, and stillbirth. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to human insulin or any excipients","Hypoglycemic episodes (active)"]
| Precautions | ["Hypoglycemia: Can occur if dose is too high, meals missed, or exercise increased without dose adjustment.","Hypokalemia: Insulin can cause rapid shift of potassium into cells, leading to hypokalemia; monitor potassium levels.","Injection site reactions: Lipodystrophy, local allergic reactions; rotate injection sites.","Systemic allergic reactions: Rare but can be serious; discontinue if suspected.","Dosage adjustment needed in renal or hepatic impairment."] |
| Food/Dietary | Alcohol can increase risk of hypoglycemia; limit consumption. Consistent carbohydrate intake is recommended to match insulin action. Avoid skipping meals after injection. Grapefruit may affect insulin sensitivity; monitor glucose. |
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| Fetal Monitoring |
| Monitor blood glucose levels frequently (pre- and postprandial) and HbA1c monthly. Fetal surveillance: ultrasound for growth and anatomy, nonstress test or biophysical profile in third trimester if indicated. Monitor for maternal hypoglycemia. |
| Fertility Effects | No direct adverse effects on fertility. Optimization of glycemic control improves ovulation and fertility outcomes in diabetic women. |
| Clinical Pearls | Use only regular insulin for intravenous infusion; do not mix with other insulins in the same syringe. Monitor serum potassium closely due to risk of hypokalemia. Onset of action is 30 minutes subcutaneously, peak at 2-4 hours, duration 5-8 hours. Administer 30 minutes before meals. For IV use, use separate line or flush with saline. Do not use if solution is cloudy or contains particulate matter. |
| Patient Advice | Rotate injection sites to prevent lipodystrophy. · Always check blood glucose before each dose. · Do not reuse needles or syringes. · Store unopened vials in refrigerator; opened vials can be stored at room temperature for up to 28 days. · Inject subcutaneously 30 minutes before meals. · Carry a source of fast-acting sugar (e.g., glucose tablets) for hypoglycemia treatment. · Wear medical alert identification. · Do not use if insulin appears cloudy or discolored. |