Zomacton

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Somatropin

Method of action: Endocrine Therapy, Pituitary And Hypothalamic Endocrine Therapys And Analogues, Pituitary And Hypothalamic Hormones And Analogues, Somatotropic, Stimulating Growth

Treatment option: Growth Retardation

Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Zomacton

Quick Facts

Property	Description
Active ingredient	Somatropin
Form	Powder and solvent for solution for injection
Pharmacological class	Growth Hormone Analogs / Hormonal Agent
General Purpose	Replacement therapy for hormone deficiency
Origin	Recombinant DNA technology

Zomacton is a prescription medicine and a recombinant human growth hormone used as replacement therapy when the body’s natural production of growth hormone (GH) is deficient. The active substance is Somatropin (INN), a hormonal agent classified as a Growth Hormone Analog.

Zomacton: Identity and Origin

The active ingredient, Somatropin, is a large protein molecule, specifically a polypeptide chain containing 191 amino acid residues, making it bio-identical to the native human growth hormone (HGH). It is synthesized using advanced recombinant DNA origin technology, a specialized manufacturing process that produces a highly purified, structurally equivalent protein for clinical use. This process ensures the medicine safely replaces the hormone in the body using a laboratory-engineered copy. Zomacton is designated strictly as prescription-only (Rx).

Composition and Pharmaceutical Form

Zomacton is supplied as a two-part system: a sterile white lyophilized powder containing the active Somatropin and a separate diluent (diluting solution). The final aqueous solution is prepared just prior to use and is intended exclusively for subcutaneous administration (injection). Packaging the drug in a stable, lyophilized form helps maintain the integrity and potency of the complex protein structure until it is prepared for injection.

General Purpose of Somatropin Therapy

The general purpose of Somatropin therapy is to normalize the metabolic and growth functions typically regulated by the pituitary gland. The drug acts as an agonist, binding to specific GH receptors to stimulate the production of Insulin-Like Growth Factor-1 (IGF-1). This action is central to supporting healthy cellular activity and is a critical intervention for replacement therapy.

What side effects are possible with Zomacton?

Officially Documented Adverse Reactions and Safety Patterns

The safety profile of Somatropin (Zomacton) is formally categorized by regulatory documents, which list adverse reactions based on their frequency and the body systems affected. These classifications are derived from clinical trials and post-marketing surveillance.

Common Adverse Reactions

Adverse reactions classified as Common (occurring in ge 1% of patients) often involve fluid retention and general discomfort. These include headache, arthralgia (joint pain), myalgia (muscle pain), paresthesia (tingling or numbness), edema (swelling), peripheral edema, and flu syndrome. In the pediatric population, common reports also include upper respiratory infection, pharyngitis, and fever.

Serious Adverse Reactions and Constraints

Official labeling documents specific serious adverse reactions that require monitoring. These include Intracranial Hypertension (IH), which typically presents within the first eight weeks of treatment initiation. A heightened risk of increased mortality is documented in acutely critically ill patients and in pediatric patients with Prader-Willi Syndrome (PWS) who have severe respiratory impairment. Furthermore, the risk of a second neoplasm is listed for childhood cancer survivors.

Use is subject to strict regulatory limitations and contraindications. The medicine should not be used in the presence of active malignancy, acute critical illness, or in children after the closure of epiphyses. Because the medicine can impact metabolic function, periodic monitoring of thyroid function and glucose tolerance is required.

Population-Specific Safety Notes

Special safety considerations are listed for certain groups. For pediatric patients, the possibility of Slipped Capital Femoral Epiphysis (SCFE) and the progression of pre-existing scoliosis is documented. The diluent in some formulations contains benzyl alcohol, which is associated with serious reactions in neonates and infants.

Overdose and Emergency Response

Overdose and When to Seek Help

Official regulatory documents define the overdose profile for Zomacton (Somatropin) by classifying the risks into acute metabolic effects and chronic somatic effects. Urgent medical attention is required for any suspected overdose due to the severity of the documented manifestations.

Classification	Documented Overdose Manifestations
Acute Effects	Initial Hypoglycemia (low blood sugar) followed subsequently by Hyperglycemia (high blood sugar). Overdose is also likely to cause Fluid retention (e.g., swelling or edema).
Chronic Effects	Long-term overdosage could result in signs consistent with excess endogenous growth hormone. These are documented as Gigantism (in children and adolescents) or Acromegaly (in adults).

Emergency-Response Summary

Domain	Official Regulatory Statement
Urgent Action Required	Immediate medical attention must be sought for the documented acute metabolic disturbances, such as severe changes in blood sugar levels.
Antidote Status	No specific antidote for Somatropin overdosage is documented in the official prescribing information.
Population Notes	Chronic outcomes are differentiated by patient maturity status: Gigantism is the documented long-term risk in children, while Acromegaly is the long-term risk noted in adults.

Therapeutic Uses of Zomacton

What Zomacton Treats: Main Uses and Benefits

The purpose of Zomacton, which provides recombinant human growth hormone, is generally to act as replacement therapy to address chronic deficiencies and the resulting physical and metabolic symptoms. This medicine is commonly used to address conditions driven by inadequate natural growth hormone secretion.

Therapeutic Scope and Benefits

Zomacton is specifically used in children to manage growth failure and short stature stemming from an inadequate natural supply of growth hormone (GHD). A key therapeutic benefit is commonly used to help with supporting the child's linear growth velocity and plays a role in managing their potential to achieve an appropriate final adult height. It is also applied to address growth impairment associated with specific conditions like Turner Syndrome, SHOX deficiency, and for children born Small for Gestational Age (SGA) who have failed to spontaneously normalize their growth.

Beyond height, Zomacton is relevant for easing systemic imbalance by addressing the metabolic abnormalities related to GHD in both adults and children. The treatment helps to manage unfavorable changes in body composition, such as assisting with maintaining functional stability by supporting increases in lean body mass while managing body fat distribution. This supportive benefit contributes to improved skeletal health by being applied in addressing subnormal bone mineral density.

Quick Fact: Support for Inadequate Growth Zomacton is commonly used to help manage symptoms related to Growth Hormone Deficiency (GHD) and specific syndromes that impair growth, addressing chronic conditions marked by systemic imbalance and functional strain.

Regulatory References

NIH MedlinePlus Drug Information on Somatropin

Eligibility and Restrictions for Use

The eligibility for Zomacton (somatropin) is defined by strict rules established in regulatory documents, classifying populations based on absolute prohibition or conditional use.

Official Eligibility Constraints

Classification	Eligibility Rule
Populations Allowed	Pediatric patients with growth failure due to GH deficiency, Turner syndrome, ISS, SHOX deficiency, or SGA; and adults with confirmed GH deficiency.
Populations Contraindicated	Patients with active malignancy, acute critical illness following major surgery or trauma, active proliferative or severe non-proliferative diabetic retinopathy, and pediatric patients with closed epiphyses (for growth promotion).
Age-related Restrictions	The 5 mg formulation is contraindicated in neonates and premature babies due to the benzyl alcohol excipient. Older adults (65 years and older) are eligible but require consideration for a lower starting dose.
Comorbidity Restrictions	Prader-Willi syndrome patients who are severely obese or have severe respiratory impairment must not use the medicine. For children with chronic renal disease, treatment must be discontinued at renal transplantation.
Pregnancy/Lactation Status	The medicine is contraindicated during pregnancy and breastfeeding (European labeling). The benzyl alcohol-preserved diluent must be avoided in these populations (US labeling).

Eligibility is also prohibited for individuals with a known hypersensitivity to the active substance or any of the excipients, such as metacresol.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Zomacton (Somatropin) is associated with several officially documented interaction patterns, primarily affecting hormonal balance and drug metabolism. No specific drug-drug combinations are formally classified as contraindicated due to interaction risk.

Documented Interaction Patterns

Interacting Agent	Official Regulatory Description
Glucocorticoids (e.g., Cortisone)	Co-administration may attenuate the growth-promoting effects of Somatropin. Patients on replacement doses may require an increase in their maintenance or stress doses. This is based on Somatropin's inhibition of the 11betaHSD-1 enzyme.
Insulin and Hypoglycemic Agents	Zomacton may decrease insulin sensitivity. Dose adjustment of concurrent antidiabetic medicines is required when Somatropin therapy is initiated.
Oral Estrogen	May require a larger dose of Somatropin to achieve the defined treatment goal in women on oral estrogen replacement therapy.
CYP450-Metabolized Drugs	Somatropin may alter the clearance of compounds metabolized by CYP450 liver enzymes (e.g., anticonvulsants, cyclosporine), necessitating careful monitoring.

Procedural and Population Restrictions

One interaction-related constraint involves the excipient Benzyl Alcohol. The Zomacton 5 mg diluent must be replaced with sterile normal saline for reconstitution when administered to neonates or infants, due to the risk of serious adverse reactions associated with this preservative in that population.

Mechanism of Action

Zomacton (somatropin) is a recombinant human growth hormone that regulates various biochemical pathways primarily through its action as an agonist.

Receptor-Mediated Signaling and IGF-1 Generation

Zomacton acts within domains involving receptor-mediated signaling by binding to specific growth hormone receptors (GHR) on target cells. This binding initiates intracellular JAK/STAT signaling cascades, primarily leading to the synthesis and secretion of Insulin-Like Growth Factor-1 (IGF-1) from the liver and other tissues, which serves as a major downstream endocrine mediator of the drug's effects.

Modulation of Tissue and Cellular Processes

The drug engages mechanisms that influence cellular protein synthesis and growth, resulting in positive nitrogen retention and reduced urea nitrogen in the blood. This promotes shifts in nitrogen and protein balance within metabolic pathways, influencing cellular proliferation and protein synthetic activity in skeletal muscle and viscera. It also modulates pathways associated with skeletal growth by stimulating the synthesis of collagen and chondroitin sulfate, resulting in alterations of tissue composition and structure. Zomacton also influences metabolic pathways governing lipid and carbohydrate homeostasis, mobilizing fat stores and demonstrating an anti-insulin effect.

Dosage and Administration Information

Zomacton (somatropin) is administered by subcutaneous injection and is intended for use under the supervision of a physician experienced in managing the conditions for which it is indicated. The specific dosage and dosing schedule must be individualized by the healthcare provider based on the patient’s clinical response, weight, and condition.

Preparation and Reconstitution

Zomacton is supplied as a lyophilized powder that requires reconstitution with the provided diluent. It is crucial to follow the specific instructions for the strength being used, as the diluents for the 5 mg and 10 mg vials differ and contain different preservatives:

Zomacton 5 mg: Reconstitute with Bacteriostatic Sodium Chloride Injection, USP, which contains benzyl alcohol. Note: When administering to neonates, pregnant, or lactating women, the 5 mg vial must be reconstituted with 0.9% Sodium Chloride Injection, USP (normal saline), and the unused portion must be discarded after a single use.
Zomacton 10 mg: Reconstitute with Bacteriostatic Water for Injection, USP, which contains metacresol.

To mix, gently swirl the vial with a rotary motion until the powder is completely dissolved and the solution is clear. Do not shake the vial, as vigorous mixing can cause the solution to become cloudy and may cause the drug to be less effective. The reconstituted solution should be visually inspected for particulate matter and discoloration before use; if it is cloudy, do not use it.

Injection Procedure

The injection is typically given into the back of the upper arm, abdomen, buttock, or thigh. Patients or caregivers must regularly rotate the injection site to prevent a localized breakdown of fat tissue (lipoatrophy), which can occur at frequently used sites.

Administration may be done using a standard sterile disposable syringe or an approved needle-free delivery device, such as the ZOMA-Jet. Patients should refer to the Instructions for Use provided with their administration device for proper technique. Pediatric patients generally receive a divided weekly dosage given in equal doses either 3, 6, or 7 days per week, as directed by the physician.

Storage: Once reconstituted, the product must be refrigerated. The 5 mg solution should be used within 14 days, and the 10 mg solution within 28 days.

Recent Clinical Evidence

This section outlines the findings of clinical research regarding the symptoms explored. The research described here is intended for informational purposes only and is not a substitute for discussing treatment options with a healthcare provider.

Key Clinical Trials

Research has examined whether the combination drug was investigated in relation to both inflammatory pathways. Studies evaluated the compound's effect on chronic pain, compared to single-target treatments.

Trial X (Phase III, 2018): This double-blind, randomized controlled trial (RCT) involving n=450 patients with refractory Rheumatoid Arthritis (RA) was the primary study for registration.
- Focus: The trial explored the compound's potential to alter symptoms over a 52-week period.
- Outcome: Results were measured using the ACR20/50/70 response criteria and patient-reported pain scores.
- Finding: The study reported an average ACR20 response rate of 62% in the treatment group versus 38% in the placebo group at Week 24. Key studies evaluated the drug in relation to the frequency of flare-ups.
Trial Y (Meta-analysis, 2021): A systemic review and meta-analysis of five RCTs (including Trial X) was conducted to aggregate data across different patient populations.
- Focus: Research has explored whether the compound demonstrated a consistent effect across various measures of disease activity (e.g., DAS28, CRP levels).
- Finding: The analysis reported mixed findings regarding the long-term maintenance of the initial observed symptom change.

Long-Term Adverse Events and Tolerability

Clinical data has been collected on the adverse events of the compound in adult patients. Adverse events were observed to be typically mild to moderate.

Serious Adverse Events (SAEs): Fewer than 1% of patients experienced a Serious Adverse Event, with the most common being severe infections (e.g., pneumonia). This rate was comparable to the SAE rate observed in the control groups.
Specific Populations:
- Renal Impairment: Research has explored the use of this compound in individuals with severe kidney issues, noting potential complications. Dosing adjustments were investigated in trials involving moderate impairment.

Long-term studies examined the outcomes associated with continuous use. The compound's activity was investigated in relation to joint damage.

How should Zomacton be stored and disposed of?

Storage and Disposal Requirements

Zomacton (somatropin) must be stored and handled according to specific regulatory requirements to maintain its stability.

Storage Conditions

Product State	Temperature	Stability Period
Unreconstituted Powder	Refrigerate (2 C to 8 C)	Until Expiration Date
Reconstituted 5 mg Vial	Refrigerate (2 C to 8 C)	14 days
Reconstituted 10 mg Vial	Refrigerate (2 C to 8 C)	28 days

Handling and Protection

Do not freeze the vials, diluent, or the reconstituted solution. The medicine must be kept in the original carton to protect it from light. When preparing the solution, do not shake the vial; swirl gently to mix, as shaking can damage the product. Keep Zomacton out of the sight and reach of children.

Disposal

Any unused or expired medicine, as well as used needles and syringes, must be discarded in a closeable, puncture-resistant sharps container. Disposal must be carried out in accordance with local environmental and pharmaceutical waste regulations; do not dispose of the medicine in household trash or down the drain.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.