Formation of Antibodies:
The development of antibodies against somatropin has been observed in some patients. The clinical significance of these antibodies is not known although until now they have proved to be antibodies with limited binding capacity and they have not been connected with growth impairment, except in patients with genetic deletions.
In very rare cases of short stature associated with deletion of the growth hormone gene, the treatment with growth hormone can lead to the formation of antibodies that impair the growth.
Any patient suffering from confirmed growth hormone deficiency who does not respond to the treatment with Saizen should be examined for the presence of antibodies against human growth hormone and the thyroid status should be determined.
Treatment with human proteins can cause hypersensitive reactions (eg, redness and itching at the site of the injection).
A deficit of the extracellular volume is characteristic in patients with growth hormone deficiency. This deficit is rapidly corrected after the start of the treatment with somatropin.
Manifestations of hypersensitivity, intolerance, hypothyroidism or hyperglycaemia, appearance of unexplained claudication or concomitant treatment with glucocorticoids (see Precautions).
Certain cases of leukemia have been reported in a small number of children suffering from growth hormone deficiency, both in children who were receiving treatment with growth hormone and those who were not treated. The incidence could be slightly higher in the children with growth hormone deficiency. A causal relationship with the growth hormone therapy has not been established.
During substitution therapy with growth hormone in adults, fluid retention is to be expected.
Oedemas, swelling of the joints, arthralgia, myalgia and paraesthesia can be clinical manifestations of fluid retention. These symptoms or clinical signs are, however, normally transient and dose-dependent. The side effects are listed according to the incidence, as follows: Very frequent: >1/10; frequent: >1/100 to <1/10; occasional: >1/1000 to <1/100; rare: >1/10,000 to <1/1000; very rare: <1/10,000.
Application Site Reactions:
Frequent injection site reactions eg, pain, paraesthesia, redness or oedema. Local lipoatrophy, which can be prevented by changing the injection site.
Nervous System Disorders:
Frequent in Adults/Occasional in Children: Paraesthesia, hypoaesthesia (only in adults). Occasional: Benign idiopathic intracranial hypertension.
Very Rare: Hypothyroidism.
Musculoskeletal, Connective Tissue and Bone Disorders:
Very Frequent in Adults (23.3%)/Occasional in Children: Arthralgia.
Frequent in Adults/Occasional in Children: Myalgia, carpal tunnel syndrome (only in adults), bone pain (only in adults), rigidity. Very Rare: Dislocation of the femoral epiphysis (epiphyseolysis capitis femoris).
Blood and Lymphatic System Disorders:
Very Frequent in Adults (up to 15%)/Occasional in Children: Oedema.
Metabolic and Nutritional Disorders:
Insulin resistance can lead to hyperinsulinism and in rare cases to hyperglycaemia.
Side effects appear mainly in the initial phase of the treatment and subside either spontaneously or after the dosage is reduced.
Adult patients with growth hormone deficiency that was already diagnosed in childhood report side effects less frequently than patients whose growth hormone deficiency was not diagnosed until adulthood.
The irregular IM administration of Saizen has been associated with the appearance of hypoglycaemia.
Side Effects Observed in the Same Therapeutic Class:
In rare cases, convulsions, exacerbation of existing psoriasis and disorders of the fluid balance can appear. Cases of gynaecomastia and premature larche have been reported with other growth hormone preparations.
There are reports of isolated cases of sleep apnoea and sudden death in patients with Prader-Willi syndrome under treatment with growth hormone. Saizen is not indicated for the treatment of patients with Prader-Willi syndrome.