Clinical efficacy of testosterone undecanoate in male hypogonadism.

Testosterone undecanoate (Restandol, Organon Laboratories Ltd) dissolved in oleic acid, was administered orally to seventy-six hypogonadal males for three consecutive 3-week periods and the subjective clinical response assessed by a standard interview. Plasma testosterone and testosterone undecanoate levels were determined by radioimmunoassay before the study and after 3, 6 and 9 weeks treatment. The treatment was effective in sixty of the sixty-six patients who completed the trial. Ten patients did not complete the trial; two for reasons unrelated to the drug and eight because of side effects, mainly gastro-intestinal. There was a significant rise in plasma testosterone levels during treatment and a positive correlation between plasma testosterone and testosterone undecanoate levels. Testosterone undecanoate is a potentially valuable drug for the oral treatment of male hypogonadism.