Long-acting testosterone undecanoate for parenteral testosterone therapy

Aksam A Yassin, Doris Huebler and Farid Saad

Testosterone as a compound for the treatment of testosterone deficiency has been available for almost 70 years; however, the pharmaceutical formulations have been less than ideal. Injectable testosterone esters have been used traditionally for treatment, but they generate supranormal testosterone levels shortly after the 2–3-weekly injections, when testosterone levels then decline very rapidly becoming subnormal in the days before the next injection. Testosterone undecanoate is a new injectable testosterone preparation with a considerably better pharmacokinetic profile. After two initial injections with a 6-week interval, the following intervals between two injections are almost always 12 weeks. Plasma testosterone levels with this preparation are almost always in the normal range. Side effects experienced with conventional testosterone esters are almost nil with this preparation.