Testosterone is characterized by a wide margin of safety.
On account of the sebum-stimulating action acne-like manifestations can occasionally occur, particularly at the beginning of treatment. In most cases this is a transient reaction which subsides spontaneously.
Rarely, gynecomastia can occur at the beginning of treatment. This is probably due to a temporary imbalance between testosterone and estrogens and usually subsides in the further course of treatment.
In isolated cases frequent or sustained erections can occur. In these cases the dose must be reduced or the preparation withdrawn in order to prevent damage resulting from a sustained erection.
Use of testosterone in high doses or over prolonged periods sometimes increases the tendency to fluid accumulation and edema.
If erythrocytosis occurs during treatment the treatment should be interrupted until the red cell count, hemotocrit and serum hemoglobin have returned to normal. Treatment can then be resumed at a lower dose or with longer injection intervals.
Use of testosterone in high doses or over prolonged periods can influence the lipid metabolism. The appropriate parameters should therefore be monitored during androgen therapy.
In predisposed men (e.g. marked obesity, chronic obstructive lung disease) sleep apnea may rarely occur. The sleep apnea disappears when the testosterone therapy is discontinued.
Contraindications
Testosterone must not be given to patients with diagnosed or suspected prostatic carcinoma. Androgen therapy does not lead to the development of prostate cancer. However, as about 80% of prostatic carcinomas are androgen-dependent, testosterone treatment could stimulate the further growth of an already existing tumor.
Androgens must not be given to patients with the very rare male breast cancer. As androgens are aromatized to estrogens, androgen therapy can stimulate proliferation of an estrogen-receptor-positive breast carcinoma. Gynecomastia, which can occur as a result of hypogonadism, is not a contraindication and usually subsides on androgen therapy.