Androgens are responsible for the growth spurt of adolescence and for the eventual termination of linear growth which is brought about by the fusion of the epiphyseal growth centers. In children, exogenous androgens accelerate linear growth rates, but may cause a disproportionate advancement in bone maturation. Use over long periods may result in fusion of the epiphyseal growth centers and termination of growth process. Androgens have been reported to stimulate the production of red blood cells by enhancing the production of erythropoietic stimulating factor.
To determine the complications, toxicities, and compliance of long term testosterone replacement in hypogonadal males, we retrospectively assessed 45 elderly hypogonadal men receiving testosterone replacement therapy and 27 hypogonadal men taking testosterone. Hypogonadism was defined as a bioavailable testosterone serum concentration of 72 ng/dL or less. Both groups received baseline physical examinations and blood tests. The testosterone-treated group received 200 mg testosterone enanthate or cypionate im every 2 weeks, and follow-up examinations and blood samplings were performed every 3 months. The control group had a single follow-up blood test and physical examination. There was no significant difference in the initial blood tests in the two groups. At 2 yr follow-up, only the hematocrit showed a statistically significant increase in the testosterone-treated group compared to the control group (P < ). A decrease in the urea nitrogen to creatinine ratio and an increase in the prostate-specific antigen concentration was not statistically significant. Eleven (24%) of the testosterone-treated subjects developed polycythemia sufficient to require phlebotomy or the temporary withholding of testosterone, one third of which occurred less than 1 yr after starting testosterone treatment. There was no significant difference in the incidence of new illness in the two groups during the 2-yr follow-up. Although self-assessment of libido was dramatically improved in the testosterone-treated group (P < ), approximately one third of the subjects discontinued therapy. In conclusion, testosterone replacement therapy appears to be well tolerated by over 84% of the subjects. Long term testosterone replacement to date appears to be a safe and effective means of treating hypogonadal elderly males, provided that frequent follow-up blood tests and examinations are performed.