Saizen

SIDE EFFECTS

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 second somatropin formulation, and may not reflect the adverse reaction rates observed in practice.

Growth Hormone Deficient Pediatric Patients

In clinical studies in which Saizen® was administered to growth hormone deficient children, the following reactions were infrequently seen: local reactions at the injection site (such as pain, numbness, redness and swelling), hypothyroidism, hypoglycemia, seizures, exacerbation of preexisting psoriasis and disturbances in fluid balance.

Growth Hormone Deficient Adult Patients

For a description of the clinical trials refer to section 14. During the 6-month placebo-controlled study, adverse reactions were reported in 56 patients (93.3%) in the somatropin-treated group and 42 patients (76.4%) in the placebo-treated group. Adverse reactions with an incidence of ≥ 5% in Saizen®-treated patients which were more frequent in Saizen®-treated patients compared with placebo-treated patients are listed in Table 1. Arthralgia, myalgia, peripheral edema, other types of edema, carpal tunnel syndrome, paraesthesia and hypoaesthesia were common in the somatropin-treated patients and reported more frequently than in the placebo group. These types of adverse reactions are thought to be related to the fluid accumulating effects of somatropin. During the placebo-controlled portion of the study, approximately 10% of patients without preexisting diabetes mellitus or impaired glucose tolerance treated with somatropin manifested mild, but persistent, abnormalities of glucose tolerance, compared with none in the placebo group. During the open label phase of the study, approximately 10% of patients treated with somatropin required a small upward adjustment of thyroid hormone replacement therapy for preexisting central hypothyroidism and 1 patient was newly diagnosed with central hypothyroidism. In addition, during the open label phase of the study, when all patients were being treated with somatropin, two patients with preexisting central hypoadrenalism required upward titration of hydrocortisone maintenance therapy which was considered to be suboptimal (unrelated to intercurrent stress, surgery or disease), and 1 patient was diagnosed de novo with central adrenal insufficiency after six months of somatropin treatment. Anti-GH antibodies were not detected.

Table 1 : Adverse Reactions with ≥ 5% Overall Incidence in Saizen®-Treated Patients Which Were More Frequent in Saizen®-Treated Patients Compared with Placebo-Treated Patients During a 6 Month Study

Adverse Reaction Saizen®-Treated
(N=60)
Placebo
(N=55)
Arthralgia 14 (23.3%) 7 (12.7%)
Headache 11 (18.3%) 8 (14.5%)
Edema peripheral 9 (15.0%) 2 (3.7%)
Myalgia 5 (8.3%) 2 (3.6%)
Paraesthesia 4 (6.7%) 1 (1.8%)
Hypoaesthesia 4 (6.7%) 0
Edema dependent 3 (5.0%) 2 (3.6%)
Skeletal Pain 3 (5.0%) 1 (1.8%)
Carpal tunnel syndrome 3 (5.0%) 1 (1.8%)
Edema generalized 3 (5.0%) 0
Chest pain 3 (5.0%) 0
Depression 3 (5.0%) 0
Hypothyroidism 3 (5.0%) 0
Insomnia 3 (5.0%) 0
N = number of patients

The adverse reaction pattern observed during the open label phase of the study was similar to the one presented above.

Post-Marketing Experience

The following adverse reactions have been identified during post approval use of Saizen®. Because these reactions 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.

Leukemia has been reported in a small number of growth hormone deficient patients treated with growth hormone. It is uncertain whether this increased risk is related to the pathology of growth hormone deficiency itself, growth hormone therapy, or other associated treatments such as radiation therapy for intracranial tumors. So far, epidemiological data fail to confirm the hypothesis of a relationship between growth hormone therapy and leukemia.

The following additional adverse reactions have been observed during the appropriate use of somatropin: headaches (children and adults), gynecomastia (children), and pancreatitis (children and adults), (see WARNINGS AND PRECAUTIONS).

Immunogenicity

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 Saizen® with the incidence of antibodies to other products may be misleading. In the case of growth hormone, antibodies with binding capacities lower than 2 mg/mL have not been associated with growth attenuation. In a very small number of patients treated with somatropin, when binding capacity was greater than 2 mg/mL, interference with the growth response was observed.

Read the Saizen (somatropin injection) Side Effects Center for a complete guide to possible side effects

DRUG INTERACTIONS

Inhibition Of 11β-Hydroxysteroid Dehydrogenase Type 1 (11βHSD-1)

The microsomal enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD-1) is required for conversion of cortisone to its active metabolite, cortisol, in hepatic and adipose tissue. GH and somatropin inhibit 11βHSD-1. Consequently, individuals with untreated GH deficiency have relative increases in 11βHSD-1 and serum cortisol. Introduction of somatropin treatment may result in inhibition of 11βHSD1 and reduced serum cortisol concentrations. As a consequence, previously undiagnosed central (secondary) hypoadrenalism may be unmasked and glucocorticoid replacement may be required in patients treated with somatropin. In addition, patients treated with glucocorticoid replacement for previously diagnosed hypoadrenalism may require an increase in their maintenance or stress doses following initiation of somatropin treatment; this may be especially true for patients treated with cortisone acetate and prednisone since conversion of these drugs to their biologically active metabolites is dependent on the activity of 11βHSD-1.

Pharmacologic Glucocorticoid Therapy And Supraphysiologic Glucocorticoid Treatment

Pharmacologic glucocorticoid therapy and supraphysiologic glucocorticoid treatment may attenuate the growth promoting effects of somatropin in children. Therefore, glucocorticoid replacement dosing should be carefully adjusted in children receiving concomitant somatropin and glucocorticoid treatments to avoid both hypoadrenalism and an inhibitory effect on growth.

Cytochrome P450-Metabolized Drugs

Limited published data indicate that somatropin treatment increases cytochrome P450 (CYP450) mediated antipyrine clearance in man. These data suggest that somatropin administration may alter the clearance of compounds known to be metabolized by CYP450 liver enzymes (e.g., corticosteroids, sex steroids, anticonvulsants, cyclosporine). Careful monitoring is advisable when somatropin is administered in combination with other drugs known to be metabolized by CYP450 liver enzymes. However, formal drug interaction studies have not been conducted.

Oral Estrogen

Because oral estrogens may reduce the serum IGF-1 response to somatropin treatment, girls and women receiving oral estrogen replacement may require greater somatropin dosages [see DOSAGE AND ADMINISTRATION].

Insulin and/or Oral/Injectable Hypoglycemic Agents

In patients with diabetes mellitus requiring drug therapy, the dose of insulin and/or oral/injectable agent may require adjustment when somatropin therapy is initiated [see WARNINGS AND PRECAUTIONS].

Last reviewed on RxList: 6/27/2014
This monograph has been modified to include the generic and brand name in many instances.

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