HUMALOG MIX 75/25
Clinical safety rating: caution
Comprehensive clinical and safety monograph for HUMALOG MIX 75/25 (HUMALOG MIX 75/25).
Biphasic insulin analog combining rapid-acting insulin lispro (25%) and intermediate-acting insulin lispro protamine suspension (75%). Insulin lispro lowers blood glucose by binding to insulin receptors, facilitating cellular glucose uptake, inhibiting hepatic gluconeogenesis, and promoting glycogenesis and lipogenesis.
| Metabolism | Primarily metabolized by hepatic degradation via insulin-degrading enzyme (IDE). Renal and hepatic clearance contribute to elimination. |
| Excretion | Renal: 60-80% as unchanged drug following subcutaneous absorption; the remaining fraction undergoes hepatic metabolism and biliary/fecal excretion. |
| Half-life | Insulin lispro: 0.5-1 hour; protamine-bound fraction prolongs absorption, resulting in a biphasic profile with an effective half-life of 2-4 hours for the 75% NPL component. |
| Protein binding | <5% bound to plasma proteins (albumin); negligible binding. |
| Volume of Distribution | 0.3-0.5 L/kg, consistent with distribution into extracellular fluid. |
| Bioavailability | Subcutaneous: approximately 80-100% (similar to regular insulin), depending on injection site and technique. |
| Onset of Action | Subcutaneous: 15-30 minutes for blood glucose reduction. |
| Duration of Action | Subcutaneous: 18-24 hours due to the 75% protamine-suspended lispro intermediate component; the duration is dose-dependent and may be shorter with smaller doses. |
Subcutaneous injection: 75% insulin lispro protamine suspension and 25% insulin lispro solution. Dose individualized based on glycemic goals and prior insulin regimen. Typical total daily dose: 0.5-1 unit/kg/day divided into two doses (pre-breakfast and pre-dinner).
| Dosage form | INJECTABLE |
| Renal impairment | eGFR <45 mL/min: Reduce dose by 25-50% due to decreased insulin clearance. Monitor glucose frequently. eGFR <30 mL/min: Further dose reduction; consider alternative insulin regimen. |
| Liver impairment | Child-Pugh class B or C: Reduce dose by 25-50% due to impaired gluconeogenesis. Monitor glucose and titrate carefully. |
| Pediatric use | Weight-based: 0.25-0.5 units/kg/day divided into two doses for type 1 diabetes; 0.5-1 unit/kg/day for type 2 diabetes. Dose should be individualized and adjusted based on glycemic response. |
| Geriatric use | Initiate at lower total daily dose (0.3-0.5 units/kg/day) due to increased risk of hypoglycemia. Titrate cautiously with frequent glucose monitoring. Avoid aggressive dosing. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for HUMALOG MIX 75/25 (HUMALOG MIX 75/25).
| Breastfeeding | Insulin lispro is excreted in breast milk in negligible amounts; no known adverse effects on infant. M/P ratio not established but considered clinically insignificant. Compatible with breastfeeding. |
| Teratogenic Risk | Insulin lispro does not cross the placenta in significant amounts; no known teratogenic risk. However, maternal hyperglycemia during first trimester increases risk of congenital malformations; uncontrolled diabetes in second and third trimesters may cause macrosomia, polyhydramnios, and neonatal hypoglycemia. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to insulin lispro or any excipients.","During episodes of hypoglycemia."]
| Precautions | ["Hypoglycemia: Most common adverse reaction; may be life-threatening. Risk increased with intensive glycemic control, missed meals, or exercise.","Medication errors: Mix-ups between Humalog Mix 75/25 and other insulins (e.g., Humalog, Humulin) can result in dosing errors.","Hypersensitivity: Local or systemic allergic reactions, including anaphylaxis.","Hyperglycemia or ketoacidosis: May occur with missed doses or illness; monitor blood glucose.","Renal or hepatic impairment: May alter insulin requirements; dose adjustment may be necessary.","Hypokalemia: Insulin can cause shift of potassium into cells; caution in patients at risk for hypokalemia."] |
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| Fetal Monitoring |
| Monitor maternal blood glucose and HbA1c regularly. Fetal monitoring: ultrasound for growth and anatomy, nonstress test or biophysical profile in third trimester. Assess for hypoglycemia and hyperglycemia. |
| Fertility Effects | No direct adverse effects on fertility. Uncontrolled diabetes can impair fertility and increase miscarriage risk; improved glycemic control may restore fertility. |