Last updated on RxList: 4/13/2020
Zomacton Side Effects Center

What Is Zomacton?

Zomacton [somatropin (rDNA origin)] for Injection is a form of growth hormone used to treat children who have growth failure due to an inadequate secretion of normal endogenous growth hormone.

What Are Side Effects of Zomacton?

Common side effects of Zomacton include:

  • headaches,
  • enlargement of breast tissue in boys (gynecomastia),
  • pancreatitis, and
  • injection-site reactions including pain and
  • bruising

Dosage for Zomacton

The recommended dose of Zomacton is up to 0.1 mg/kg administered subcutaneously three (3) times per week (up to 0.3 mg/kg/week).

What Drugs, Substances, or Supplements Interact with Zomacton?

Zomacton may interact with drugs metabolized by the CP450 enzyme system. Tell your doctor all medications and supplements you use.

Zomacton During Pregnancy and Breastfeeding

During pregnancy, Zomacton should be used only if prescribed. It is unknown if it would harm a fetus. It is unknown if Zomacton passes into breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Zomacton [somatropin (rDNA origin)] for Injection Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Zomacton Consumer Information

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Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Serious breathing problems may occur in patients with Prader-Willi syndrome who use somatropin. If you have Prader-Willi syndrome, call your doctor promptly if you develop signs of lung or breathing problems such as shortness of breath, coughing, or new or increased snoring.

Also call your doctor at once if you have:

  • pain in your knees or hips, walking with a limp;
  • ear pain, swelling, warmth, or drainage;
  • numbness or tingling in your wrist, hand, or fingers;
  • severe swelling or puffiness in your hands and feet;
  • changes in behavior;
  • vision problems, unusual headaches;
  • changes in the shape or size of a mole;
  • pain or swelling in your joints;
  • pancreatitis--severe pain in your upper stomach spreading to your back, nausea and vomiting;
  • high blood sugar--increased thirst, increased urination, dry mouth, fruity breath odor;
  • increased pressure inside the skull--severe headaches, ringing in your ears, dizziness, nausea, vision problems, pain behind your eyes; or
  • signs of an adrenal gland problem--extreme weakness, severe dizziness, weight loss, changes in skin color, feeling very weak or tired.

Common side effects may include:

  • pain, itching, or skin changes where the medicine was injected;
  • swelling, rapid weight gain;
  • muscle or joint pain;
  • numbness or tingling;
  • stomach pain, gas;
  • headache, back pain; or
  • cold or flu symptoms, stuffy nose, sneezing, sore throat, ear pain.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Zomacton (Somatropin (rDNA origin) for Injection)

Zomacton Professional Information


The following important adverse reactions are also described elsewhere in the labeling:

  • Increased mortality in patients with acute critical illness [see WARNINGS AND PRECAUTIONS]
  • Fatalities in pediatric patients with Prader-Willi syndrome [see WARNINGS AND PRECAUTIONS]
  • Glucose intolerance and diabetes mellitus [see WARNINGS AND PRECAUTIONS]
  • Intracranial hypertension [see WARNINGS AND PRECAUTIONS]
  • Severe hypersensitivity [see WARNINGS AND PRECAUTIONS]
  • Fluid retention [see WARNINGS AND PRECAUTIONS]
  • Hypoadrenalism [see WARNINGS AND PRECAUTIONS]
  • Hypothyroidism [see WARNINGS AND PRECAUTIONS]
  • Slipped capital femoral epiphysis in pediatric patients [see WARNINGS AND PRECAUTIONS]
  • Progression of preexisting scoliosis in pediatric patients [see WARNINGS AND PRECAUTIONS]
  • Pancreatitis [see WARNINGS AND PRECAUTIONS]
  • Risk of Serious Adverse Reactions in Infants due to Benzyl Alcohol Preservative [see WARNINGS AND PRECAUTIONS]
  • Lipoatrophy [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under varying conditions, adverse reaction rates observed during the clinical trials performed with one somatropin formulation cannot always be directly compared to the rates observed during the clinical trials performed with a different approved somatropin formulation, and may not reflect the adverse reaction rates observed in practice.

Pediatric Patients

Growth Failure due to Inadequate Secretion of Endogenous Growth Hormone

ZOMACTON was evaluated in 164 pediatric patients with short stature due to GHD in an open-label study for 24 weeks. The subjects ranged in age from 2.1 to 17.7 years with a mean of 10.8 years. One hundred twenty (73%) of the subjects were male and 44 (27%) were female. Two subjects were Asian, 12 were Black, 130 were Caucasian, and 20 were categorized as ‘other’.

Table 1: Adverse Reactions ≥ 5% in Pediatric Patients with Growth Failure Due to GHD Treated with ZOMACTON through 24 Weeks

Adverse Reaction24 Week Exposure to ZOMACTON
Upper respiratory infection32%
Otitis Media10%
Increased cough9%
Abdominal pain7%
Maculopapular rash6%

All pediatric patients were carefully observed for signs or laboratory abnormalities of hypothyroidism. Fifteen patients had T4 values which occasionally fell below the central laboratory’s lower limit of normal; T4 levels rose to normal when tested during the next visit for all patients except one who continued to be monitored. Six of the 15 patients received thyroxine therapy before and throughout the study period, and thyroxine dose adjustments were made during the study in 3/6 subjects.

In studies with GH deficient pediatric patients, injection site pain was reported in 1.6% of patients. A mild and transient edema, which appeared in 1.6% of patients, was observed early during the course of treatment.

Short Stature Associated with Turner Syndrome

In a randomized, concurrent-controlled, open-label study, there was an increase in the occurrence of otitis media, ear disorders and surgical procedures in patients receiving another somatropin product at a dose of 0.3 mg/kg/week, compared with untreated control patients (Table 2). A similar increase in otitis media was observed in an 18-month placebo-controlled study.

Table 2: Adverse Reactions Occurring in Patients with Turner Syndrome Treated with 0.3 mg/kg/week of Another Somatropin Product During a 4.7 Year Randomized Open-Label Study

Surgical procedure27%45%
Otitis media26%43%
Ear disorders5%18%

Idiopathic Short Stature

Adverse reactions from a randomized, placebo-controlled study of another somatropin product dosed at 0.22 mg/kg/week are presented in Table 3. Mean fasting serum insulin concentration increased 10% in the group treated with another somatropin product at the end of treatment relative to baseline, but remained within the normal reference range.

Table 3: Adverse Reactions Occurring in Patients with Idiopathic Short Stature Treated with Another Somatropin Product during a 4.4 Year Randomized Placebo-Controlled Study

Adverse ReactionsPlacebo
Another Somatropin Product
Otitis media7%16%
Hip pain0%3%

In a dose-response study with 239 patients treated for 2 years, mean fasting blood glucose, mean glycosylated hemoglobin, and the incidence of elevated fasting blood glucose concentrations were similar among dose groups. One patient developed glucose intolerance and high serum HbA1c.

Short Stature or Growth Failure in SHOX Deficiency

Adverse reactions from a 2-year open-label study with another somatropin product compared to no treatment are presented in Table 4. During the study, the proportion of patients who had at least one IGF-1 concentration greater than 2.0 SD above the age-and gender-appropriate mean was 37.0% for the somatropin-treated group vs. 0% patients for the untreated group. The proportion of patients who had at least one IGFBP-3 concentration greater than 2.0 SD above the age and gender appropriate mean was 59% for the somatropin treated group vs. 29% for the untreated group.

Table 4: Adverse Reactions Occurring in Patients with SHOX Deficiency Treated with Another Somatropin Product for 2 years

Another Somatropin Product
Excessive number of cutaneous nevi0%7%

Small for Gestational Age (SGA) with No Catch-up Growth by 2 Years to 4 Years of Age

In a 2-year study, 193 pediatric patients were treated with another somatropin product using 2 different treatment regimens: a fixed dose of 0.067 mg/kg/day (FHD group) or an individually adjusted dose regimen (IAD group; starting dose 0.035 mg/kg/day which could be increased as early as Month 3 to 0.067 mg/kg/day based on a validated growth prediction model). Adverse reactions included common childhood infectious diseases, otitis media, headaches, and slipped capital femoral epiphysis (n=1). Six patients (4 in the FHD group and 2 in the IAD group whose dose was increased from 0.035 mg/kg/day to 0.067 mg/kg/day [one at Month 3 and one at Year 1])) had impaired fasting glucose at Year 2. Two of 6 had impaired fasting glucose during the study, and 1 discontinued treatment at month 15 as a consequence. At study completion, 20-25% of patients had serum IGF-1 SDS values > +2.

The following adverse reactions were reported from an observational study of 340 pediatric patients who received another somatropin product with an average dosage of 0.041 mg/kg/day for an average of 3 years: type 2 diabetes mellitus (n=1), carpal tunnel syndrome (n=1) and exacerbation of preexisting scoliosis (n=1).

Adult Patients

Adult-Onset GH Deficiency

In the first 6 months of controlled blinded trials during which patients received either another somatropin product or placebo, patients who received this other somatropin product experienced a statistically significant increase in edema (another somatropin product 17% vs. placebo 4%, p=0.043) and peripheral edema (12% vs. 0%, respectively, p=0.017). Edema, muscle pain, joint pain, and joint disorder were reported early in therapy and tended to be transient or responsive to dosage titration. Two of 113 patients developed carpal tunnel syndrome after beginning maintenance therapy without a low dose (0.00625 mg/kg/day) lead-in phase. Symptoms abated in these patients after dosage reduction.

All adverse reactions with ≥5% overall occurrence rate during 12 or 18 months of replacement therapy with another somatropin product are shown in Table 5 (adult-onset patients) and in Table 6 (childhood-onset patients).

Adult patients treated with another somatropin product who had been diagnosed with GH deficiency in childhood reported adverse reactions less frequently than those with adult-onset GH deficiency.

Table 5: Adverse Reactions Occurring ≥5% in Adult-Onset Growth Hormone-Deficient Patients Treated with Another Somatropin Product for 18 Months as Compared with 6-Month Placebo and 12-Month Exposure to Another Somatropin Producta

Adverse Reaction18 Months Exposure [Placebo (6 Months)/GH (12 Months)]
18 Months GH Exposure
Peripheral edemac17%12%
Back pain11%10%
Joint disorder2%6%
Surgical procedure2%6%
Flu syndrome7%4%
a Abbreviations: GH= another somatropin product; n=number of patients receiving treatment in the period stated
b p=0.04 as compared to placebo (6 months).
c p=0.02 as compared to placebo (6 months).

Childhood-Onset GH Deficiency

Two double-blind, placebo-controlled trials were conducted in 67 adult patients who had received previous somatropin treatment during childhood. Patients were randomized to receive either placebo injections or another somatropin product (0.00625 mg/kg/day for the first 4 weeks, then 0.0125 mg/kg/day thereafter) for the first 6 months, followed by open-label use of another somatropin product for the next 12 months for all patients. The patients in these studies reported side effects less frequently than those with adult-onset GH deficiency. During the placebo-controlled phase (first 6 months) of the study, elevations of serum glutamic oxaloacetic transferase were reported significantly more often for somatropin-treated (12.5%) than placebo-treated patients (0.0%, p=0.031). No other events were reported significantly more often for somatropin-treated patients during the placebo-controlled phase.

Table 6: Adverse Reactions Occurring ≥5% in Childhood-Onset Growth Hormone-Deficient Patients Treated with Another Somatropin Product for 18 Months as Compared with 6-Month Placebo and 12-Month Exposure to Another Somatropin Producta

Adverse Reaction18 Months Exposure [Placebo (6 Months)/GH (12 Months)]
18 Months GH Exposure
Flu syndrome23%16%
AST increasedb6%13%
Cough increased0%6%
ALT increased6%6%
Respiratory disorder6%3%
a Abbreviations: GH=another somatropin product; n=number of patients receiving treatment in the period stated;
ALT=alanine aminotransferase, formerly SGPT;
AST=aspartate aminotransferase, formerly SGOT.
b p=0.03 as compared to placebo (6 months).

In an ongoing post-marketing observational study of treatment with another somatropin product in 3,102 GH-deficient adults, hypertension, dyspnea, and sleep apnea were reported by 1% to less than 10% of patients after various durations of treatment.


As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to ZOMACTON in the studies described below with the incidence of antibodies in other studies or to other products may be misleading.

In a clinical trial with another recombinant growth hormone during the first 6 months of somatropin therapy in 314 naive patients, 1.6% developed specific antibodies to somatropin (binding capacity ≥0.02 mg/L). None had antibody concentrations which exceeded 2 mg/L. Throughout 8 years of this same study, two patients (0.6%) had binding capacity >2 mg/L. Neither patient demonstrated a decrease in growth velocity at or near the time of increased antibody production. It has been reported that growth attenuation from pituitary-derived GH may occur when antibody concentrations are >1.5 mg/L.

Post-Marketing Experience

Because the following adverse events are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Severe Hypersensitivity Reactions - Serious systemic hypersensitivity reactions including anaphylactic reactions and angioedema

Neurologic - Headaches (common in pediatric patients and occasional in adults)

Skin - Increase in size or number of cutaneous nevi

Endocrine - Gynecomastia.

Gastrointestinal - Pancreatitis

Metabolic - New-onset type 2 diabetes mellitus

Neoplasia - Leukemia has been reported in a small number of GH deficient pediatric patients treated with somatropin, somatrem (methionylated rhGH), and GH of pituitary origin.

Read the entire FDA prescribing information for Zomacton (Somatropin (rDNA origin) for Injection)

© Zomacton Patient Information is supplied by Cerner Multum, Inc. and Zomacton Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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