The most frequently observed adverse reaction was injection site pain (10%).
The following adverse reactions were reported in clinical trials with a suspected relationship to Nebido (according to the HARTS Body System and Dictionary Term system):
Common* (>1/100, <1/10):
Digestive: Diarrhea. Musculoskeletal System:
Leg pain, arthralgia. Nervous System: Dizziness, increased sweating, headache. Respiratory System: Respiratory disorder. Skin and Appendages: Acne, breast pain, gynecomastia, pruritus, skin disorder. Urogenital:
Testicular pain, prostate disorder. General Disorders and Administration Site Conditions:
Subcutaneous hematoma at the injection site.
*Due to the small sample size of the studies, the frequency of each reported adverse event with a suggested causal relationship falls at least into the category common (>1/100).
In the literature, the following adverse reactions from testosterone-containing preparations have been reported:
Blood and the Lymphatic System Disorders:
Rare cases of polycythemia (erythrocytosis).
Metabolism and Nutrition Disorders:
Weight gain, electrolyte changes (retention of sodium, chloride, potassium, calcium, inorganic phosphate and water) during high dose and/or prolonged treatment.
Nervousness, hostility, depression.
In very rare cases, jaundice and liver function test abnormalities.
Skin and Appendages:
Various skin reactions may occur including acne, seborrhea and balding (alopecia).
Reproductive System and Breast Disorders:
Libido changes, increased frequency of erections; therapy with high doses of testosterone preparations commonly reversibly interrupts or reduces spermatogenesis, thereby reducing the size of the testicles; testosterone replacement therapy of hypogonadism can, in rare cases, cause persistent, painful erections (priapism), prostate abnormalities, prostate cancer**, urinary obstruction.
General Disorders and Administration Site Conditions:
High-dose or long-term administration of testosterone occasionally increases the occurrences of water retention and edema; hypersensitivity reactions may occur.
**Data on prostate cancer risk in association with testosterone therapy are inconclusive.