FIASP PENFILL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FIASP PENFILL (FIASP PENFILL).
Insulin aspart is a rapid-acting insulin analog that lowers blood glucose by stimulating peripheral glucose uptake, especially by skeletal muscle and fat, and by inhibiting hepatic glucose production. It also inhibits lipolysis and proteolysis and enhances protein synthesis.
| Metabolism | Insulin aspart is metabolized primarily by proteolytic enzymes, likely insulin-degrading enzyme (IDE). It has a half-life of approximately 1.2 hours after subcutaneous administration. |
| Excretion | Primarily renal (glomerular filtration and tubular reabsorption); less than 1% excreted unchanged in bile/feces. |
| Half-life | 0.5–1.0 hours (subcutaneous); terminal half-life corresponds to absorption rate-limited elimination due to rapid dissociation from insulin receptor. |
| Protein binding | <5% bound to plasma proteins (primarily albumin; binding is negligible and not clinically significant). |
| Volume of Distribution | 0.2–0.4 L/kg (insulin aspart distributes mainly into extracellular fluid; rapid equilibration). |
| Bioavailability | Subcutaneous: approximately 60–70% (due to local degradation); intravenous: 100%. |
| Onset of Action | Subcutaneous: 10–20 minutes; intravenous: immediate (within 1 minute). |
| Duration of Action | Subcutaneous: 3–5 hours (dose-dependent); shorter than regular human insulin due to faster absorption. |
Subcutaneous injection. Individualized based on blood glucose levels. Typical starting dose for type 1 diabetes: 0.5-1.0 units/kg/day divided into multiple doses, with 50-70% as mealtime insulin and remainder as basal. For type 2 diabetes: 4-6 units with largest meal, titrated up by 2 units every 3-4 days based on glucose monitoring.
| Dosage form | SOLUTION |
| Renal impairment | No specific dose adjustment provided in labeling. Use caution; monitor glucose closely and reduce dose as needed due to prolonged insulin action in renal impairment. |
| Liver impairment | No specific dose adjustment provided in labeling. Use caution; monitor glucose closely and reduce dose as needed due to decreased gluconeogenesis in hepatic impairment. |
| Pediatric use | Children aged 1-17 years: Individualized. Typical total daily insulin dose: 0.5-1.0 units/kg/day. For once-daily injections: starting dose 0.25-0.5 units/kg/day. Administer subcutaneously with meals or within 20 minutes after starting a meal. |
| Geriatric use | Elderly patients: Start with lower doses (e.g., 2-4 units per meal) and titrate slowly to avoid hypoglycemia. Monitor renal function and adjust dose accordingly. Individualize based on glucose targets and concurrent medications. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FIASP PENFILL (FIASP PENFILL).
| Breastfeeding | Insulin aspart is excreted into breast milk in trace amounts. M/P ratio not established. Unlikely to affect the nursing infant due to oral bioavailability. Use during breastfeeding is considered safe. |
| Teratogenic Risk | Insulin aspart (FIASP PENFILL) does not cross the placenta in significant amounts. No evidence of teratogenicity in human pregnancies. Poorly controlled maternal diabetes carries risks including congenital anomalies, macrosomia, and neonatal hypoglycemia. |
| Fetal Monitoring |
■ FDA Black Box Warning
Never share a FIASP PenFill between patients, even if the needle is changed. Sharing poses a risk for transmission of blood-borne pathogens.
| Serious Effects |
["Hypersensitivity to insulin aspart or any excipients","During episodes of hypoglycemia"]
| Precautions | ["Changes in insulin strength, manufacturer, type, or method of administration may affect glycemic control and predispose to hypoglycemia or hyperglycemia","Hypoglycemia is the most common adverse effect and may be life-threatening","Monitor glucose closely in patients with renal or hepatic impairment","May cause hypokalemia if not monitored","Use with caution in patients with history of hypoglycemia unawareness"] |
| Food/Dietary | No specific food restrictions are required with FIASP. However, patients should coordinate carbohydrate intake with insulin timing. Avoid alcohol consumption which can increase risk of hypoglycemia. Grapefruit does not interact with insulin. High-fat or high-fiber meals may delay absorption of carbohydrates and affect postprandial glucose response, requiring dose adjustment. |
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| Monitor maternal blood glucose and HbA1c closely throughout pregnancy. Fetal monitoring: ultrasound for growth and anatomy, nonstress tests, and biophysical profiles as per standard diabetes management. |
| Fertility Effects | No known adverse effects on fertility. Improved glycemic control may restore fertility in diabetic patients. |
| Clinical Pearls | FIASP (faster-acting insulin aspart) has a more rapid onset of action (approx. 2.5 minutes faster than insulin aspart) and earlier peak effect, making it ideal for postprandial glucose control. Administer at start of meal or within 20 minutes after starting meal. Use with caution in patients with gastroparesis due to ultra-rapid absorption. For pump use, compatible with Medtronic and other insulin pumps; ensure no air bubbles in cartridge. Monitor for hypoglycemia, especially in first 4 hours post-injection. Do not mix with other insulins in syringe or vial. |
| Patient Advice | FIASP works faster than regular insulin aspart; inject at the beginning of a meal or within 20 minutes after starting to eat. · Do not use if the solution is cloudy or contains particles; it should be clear and colorless. · Store unopened vials or cartridges in the refrigerator (36°F to 46°F). Once opened, can be kept at room temperature (up to 86°F) for up to 28 days. · Rotate injection sites within the same body area (abdomen, thigh, arm, or buttock) to avoid lipodystrophy. · Always have a fast-acting source of sugar (glucose tablets, juice) available to treat hypoglycemia. · Do not reuse needles; dispose of sharps in a puncture-proof container. · Consult healthcare provider before adjusting doses, especially during illness, travel, or changes in physical activity. |