NUTROPIN AQ PEN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NUTROPIN AQ PEN (NUTROPIN AQ PEN).
Recombinant human growth hormone (somatropin) that binds to growth hormone receptors, activating JAK2/STAT5 signaling, promoting linear growth, increasing IGF-1 synthesis, and enhancing protein synthesis, lipolysis, and carbohydrate metabolism.
| Metabolism | Hepatic metabolism via proteolytic degradation; primarily metabolized in the liver and kidneys. Approximately 80% excreted in urine as intact or degraded fragments. |
| Excretion | Primarily renal (glomerular filtration and tubular reabsorption); less than 0.1% of the administered dose is excreted unchanged in urine. The majority is metabolized in the liver and kidneys via proteolysis, and metabolites are excreted renally. |
| Half-life | Terminal elimination half-life is approximately 2.6 to 3.6 hours after subcutaneous administration. In clinical practice, this short half-life supports daily dosing. |
| Protein binding | Approximately 50% bound to growth hormone-binding protein (GHBP) in plasma, which is a soluble form of the growth hormone receptor. |
| Volume of Distribution | Apparent volume of distribution is approximately 0.07 L/kg, suggesting limited distribution out of the vascular space and into extracellular fluid. |
| Bioavailability | Subcutaneous: Approximately 80% (range 75-90%) after subcutaneous injection compared to intravenous administration. |
| Onset of Action | Subcutaneous: Stimulation of linear growth is observed within 3 to 6 months of continuous therapy. Metabolic effects (e.g., lipolysis, increased IGF-1 levels) occur within hours to days. |
| Duration of Action | Subcutaneous: The duration of metabolic effects (e.g., suppression of glucose uptake, stimulation of lipolysis) lasts approximately 12 to 24 hours, supporting once-daily dosing. Growth promotion requires months to years of continuous therapy. |
0.2 mg subcutaneously 3 times per week for growth hormone deficiency; dose adjusted based on patient response and serum IGF-1 levels.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment guidelines for renal impairment; use with caution in severe renal impairment (GFR <15 mL/min) as clearance may be reduced. |
| Liver impairment | No specific dose adjustment guidelines for hepatic impairment; use with caution in severe hepatic impairment (Child-Pugh class C) due to potential altered clearance. |
| Pediatric use | 0.16-0.24 mg/kg subcutaneously 3 times per week for growth hormone deficiency; dose titrated based on growth response and serum IGF-1 levels. |
| Geriatric use | Initiate at lower doses (0.1-0.2 mg subcutaneously 3 times per week) due to increased risk of adverse effects; monitor for fluid retention and glucose intolerance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NUTROPIN AQ PEN (NUTROPIN AQ PEN).
| Breastfeeding | It is unknown if somatropin is excreted in human milk. No M/P ratio available. Caution should be exercised when administered to a nursing woman. Due to the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or discontinue the drug. |
| Teratogenic Risk | Somatropin is not recommended for use during pregnancy unless clearly needed. There are no adequate and well-controlled studies in pregnant women. Animal studies have not demonstrated teratogenic effects, but fetal growth retardation has been observed in rats at high doses. Risk to fetus cannot be ruled out. First trimester: insufficient data; second and third trimesters: no known specific risks but lack of robust human data. |
■ FDA Black Box Warning
Increased mortality in patients with acute critical illness due to complications following open heart surgery, abdominal surgery, or multiple accidental trauma. Contraindicated in pediatric patients with Prader-Willi syndrome who are severely obese or have severe respiratory impairment.
| Serious Effects |
Acute critical illness with complications, active malignancy, diabetic retinopathy, hypersensitivity to somatropin or excipients, closed epiphyses in pediatric patients (for growth promotion), Prader-Willi syndrome with obesity or respiratory impairment.
| Precautions | Monitor for intracranial hypertension, slipped capital femoral epiphysis, progression of scoliosis, pancreatitis, glucose intolerance, and hypersensitivity reactions. In adults, monitor for fluid retention, carpal tunnel syndrome, and arthralgias. Avoid in patients with active malignancy. |
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| Fetal Monitoring | Monitor maternal serum IGF-1 levels, glucose metabolism (blood glucose, HbA1c), and thyroid function (TSH, free T4). Monitor fetal growth via ultrasound if used during pregnancy. Assess for signs of intracranial hypertension (papilledema, headache, visual changes) in the mother. |
| Fertility Effects | Somatropin may improve fertility in women with growth hormone deficiency by enhancing ovarian response to gonadotropins. However, its use in fertility treatment should be individualized. No specific data on adverse fertility effects in males or females beyond primary indication. |