NORDITROPIN FLEXPRO

Clinical safety rating: caution

Comprehensive clinical and safety monograph for NORDITROPIN FLEXPRO (NORDITROPIN FLEXPRO).

How it works

Somatropin (recombinant human growth hormone) binds to growth hormone receptors, activating JAK2/STAT5 signaling, leading to increased IGF-1 synthesis, linear growth, and metabolic effects including lipolysis, protein synthesis, and glucose counterregulation.

What the body does with it

Metabolism	Somatropin undergoes hepatic and renal catabolism; approximately 80% is metabolized via liver proteolysis. Systemic clearance is primarily via renal filtration and tubular reabsorption with subsequent lysosomal degradation.
Excretion	Renal: approximately 70% as intact hormone; biliary/fecal: minimal, less than 5%.
Half-life	Terminal elimination half-life: 2-3 hours (subcutaneous); clinical context: requires once-daily dosing due to short half-life.
Protein binding	Approximately 30-40% bound to growth hormone-binding protein (GHBP) in plasma.
Volume of Distribution	Approximately 0.5-1.0 L/kg; indicates distribution primarily into extracellular fluid and well-perfused tissues.
Bioavailability	Subcutaneous: approximately 80% (range 70-90%); intramuscular: approximately 75%; intravenous: 100%.
Onset of Action	Subcutaneous: 2-3 hours for increase in insulin-like growth factor-1 (IGF-1) levels; maximal effect on linear growth seen after several months of therapy.
Duration of Action	Subcutaneous: 12-18 hours for metabolic effects (e.g., lipolysis, protein synthesis); growth promotion requires daily administration.

Classification & Brands

Dosing & administration

0.2-0.3 mg/kg/week subcutaneously divided into 6-7 daily doses; typical adult replacement dose is 0.2-0.5 mg/day subcutaneously.

Dosage form	INJECTABLE
Renal impairment	Not recommended in patients with GFR <30 mL/min/1.73 m²; no specific dosing guidelines for GFR 30-89 mL/min/1.73 m².
Liver impairment	No specific Child-Pugh based guidelines; caution in severe hepatic impairment due to altered growth hormone clearance.
Pediatric use	0.16-0.24 mg/kg/week subcutaneously divided into 6-7 daily doses; dosing based on growth hormone deficiency diagnosis.
Geriatric use	Initiate at 0.1-0.2 mg/day subcutaneously, titrate based on IGF-1 levels; lower starting doses due to increased sensitivity to growth hormone and higher risk of adverse effects.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for NORDITROPIN FLEXPRO (NORDITROPIN FLEXPRO).

Breastfeeding	Somatropin is excreted in breast milk in low concentrations; M/P ratio not established. Caution in nursing mothers, but risk to infant considered low due to poor oral bioavailability.
Teratogenic Risk	Somatropin is not teratogenic in animal studies. There are no adequate human studies in pregnancy; use only if clearly needed. Fetal risks are unknown but theoretical as growth hormone does not cross the placenta in significant amounts.
Fetal Monitoring

Warnings & precautions

■ FDA Black Box Warning

Increased risk of mortality in pediatric patients with Prader-Willi syndrome who are severely obese or have respiratory impairment. Do not use in patients with active malignancy or in those with acute critical illness due to complications following open heart surgery, abdominal surgery, or multiple accidental trauma.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Active malignancy","Acute critical illness (e.g., after open heart surgery, abdominal surgery, or trauma with respiratory failure)","Pediatric patients with Prader-Willi syndrome who are severely obese or have severe respiratory impairment","Diabetic retinopathy (active proliferative or severe non-proliferative)","Hypersensitivity to somatropin or excipients"]

Clinical Precautions

Precautions

["Increased risk of neoplasia (monitor for new or recurrent malignancy)","Slip capital femoral epiphysis (monitor for hip pain/limp)","Benign intracranial hypertension (papilledema)","Fluid retention (peripheral edema, arthralgia)","Glucose intolerance/diabetes mellitus (monitor blood glucose)","Pancreatitis (especially in children)","Hypersensitivity reactions","Injection site lipoatrophy"]

Clinical Tips & Counseling

Drug interactions

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NORDITROPIN FLEXPRO

Clinical safety rating: caution

Comprehensive clinical and safety monograph for NORDITROPIN FLEXPRO (NORDITROPIN FLEXPRO).

How it works

What the body does with it

Metabolism	Somatropin undergoes hepatic and renal catabolism; approximately 80% is metabolized via liver proteolysis. Systemic clearance is primarily via renal filtration and tubular reabsorption with subsequent lysosomal degradation.
Excretion	Renal: approximately 70% as intact hormone; biliary/fecal: minimal, less than 5%.
Half-life	Terminal elimination half-life: 2-3 hours (subcutaneous); clinical context: requires once-daily dosing due to short half-life.
Protein binding	Approximately 30-40% bound to growth hormone-binding protein (GHBP) in plasma.
Volume of Distribution	Approximately 0.5-1.0 L/kg; indicates distribution primarily into extracellular fluid and well-perfused tissues.
Bioavailability	Subcutaneous: approximately 80% (range 70-90%); intramuscular: approximately 75%; intravenous: 100%.
Onset of Action	Subcutaneous: 2-3 hours for increase in insulin-like growth factor-1 (IGF-1) levels; maximal effect on linear growth seen after several months of therapy.
Duration of Action	Subcutaneous: 12-18 hours for metabolic effects (e.g., lipolysis, protein synthesis); growth promotion requires daily administration.

Classification & Brands

Dosing & administration

0.2-0.3 mg/kg/week subcutaneously divided into 6-7 daily doses; typical adult replacement dose is 0.2-0.5 mg/day subcutaneously.

Dosage form	INJECTABLE
Renal impairment	Not recommended in patients with GFR <30 mL/min/1.73 m²; no specific dosing guidelines for GFR 30-89 mL/min/1.73 m².
Liver impairment	No specific Child-Pugh based guidelines; caution in severe hepatic impairment due to altered growth hormone clearance.
Pediatric use	0.16-0.24 mg/kg/week subcutaneously divided into 6-7 daily doses; dosing based on growth hormone deficiency diagnosis.
Geriatric use	Initiate at 0.1-0.2 mg/day subcutaneously, titrate based on IGF-1 levels; lower starting doses due to increased sensitivity to growth hormone and higher risk of adverse effects.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for NORDITROPIN FLEXPRO (NORDITROPIN FLEXPRO).

Breastfeeding	Somatropin is excreted in breast milk in low concentrations; M/P ratio not established. Caution in nursing mothers, but risk to infant considered low due to poor oral bioavailability.
Teratogenic Risk	Somatropin is not teratogenic in animal studies. There are no adequate human studies in pregnancy; use only if clearly needed. Fetal risks are unknown but theoretical as growth hormone does not cross the placenta in significant amounts.
Fetal Monitoring