Drug Guide

Generic Name

Somatropin

Brand Names Humatrope, Saizen, Bio-tropin, Zomacton, Nutropin, Genotropin Preservative Free, Genotropin, Nutropin Aq, Nutropin Aq Pen, Nutropin Aq Nuspin, Serostim, Serostim Lq, Norditropin, Norditropin Nordiflex, Norditropin Flexpro, Omnitrope, Accretropin

Classification

Therapeutic: Growth hormone deficiency, Pediatric and Adult

Pharmacological: Recombinant human growth hormone

FDA Approved Indications

Growth failure due to inadequate endogenous growth hormone secretion in children and adults
In children, for growth failure associated with chronic kidney disease, Turner syndrome, Prader-Willi syndrome, small for gestational age, and idiopathic short stature
In adults, for growth hormone deficiency

Mechanism of Action

Somatropin is a recombinant form of human growth hormone that stimulates growth in tissue and muscle, promotes lipolysis, and increases amino acid uptake, leading to growth and metabolic effects similar to endogenous growth hormone.

Dosage and Administration

Adult: Typically 0.2-0.3 mg/day administered subcutaneously, titrated according to clinical response and IGF-1 levels.

Pediatric: Dosing varies based on indication, generally 0.025-0.035 mg/kg/week divided into daily doses, administered subcutaneously.

Geriatric: Use with caution; start at lower doses due to increased risk of side effects.

Renal Impairment: Adjust doses cautiously; monitor closely.

Hepatic Impairment: Use with caution; monitor closely.

Pharmacokinetics

Absorption: Subcutaneous administration with variable absorption depending on formulation and site.

Distribution: Distributed to extracellular fluid compartments.

Metabolism: Metabolized in the liver and other tissues.

Excretion: Metabolites excreted primarily in urine.

Half Life: Approximately 3-5 hours.

Contraindications

Active malignancy
Closed epiphyses in children
Allergy to somatropin or excipients

Precautions

Diacrisis of intracranial hypertension
Diabetic patients, risk of hyperglycemia or diabetes mellitus
Thyroid function abnormalities, monitor and treat appropriately

Adverse Reactions - Common

Injection site reactions (Common)
Headache, edema (Common)
Pain in extremity (Common)

Adverse Reactions - Serious

Increased intracranial pressure (Papilledema) (Rare)
Progression of malignancy (Rare)
Hypoglycemia or hyperglycemia (Uncommon)

Drug-Drug Interactions

Glucocorticoids (may antagonize growth-promoting effects)
Other anabolic agents

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor growth velocity in children, IGF-1 levels, thyroid function, glucose levels, and signs of increased intracranial pressure.

Diagnoses:

Risk for hypoglycemia or hyperglycemia
Risk of ineffective tissue perfusion

Implementation: Administer subcutaneously as prescribed; rotate injection sites; monitor response and adverse effects.

Evaluation: Assess growth response, metabolic parameters, and side effects.

Patient/Family Teaching

Instruct on proper injection technique and site rotation.
Report any visual changes, persistent headaches, or severe pain.
Monitor blood glucose levels as advised.

Special Considerations

Black Box Warnings:

Potential for increased risk of mortality in children receiving growth hormone for non-growth hormone deficiency uses such as idiopathic short stature or simply for athletic enhancement.

Genetic Factors: Monitor for mutations associated with increased cancer risk,

Lab Test Interference: May affect thyroid function tests and glucose metabolism testing.

Overdose Management

Signs/Symptoms: Unusual weight gain, edema, hyperglycemia, jaw pain or swelling.

Treatment: Discontinue somatropin; symptomatic management; supportive care; monitor metabolic parameters.

Storage and Handling

Storage: Refrigerate (2-8°C), protect from light.

Stability: Stable until expiry date when refrigerated; some formulations may be stored at room temperature temporarily after opening.