Endocr Rev, Vol. 34 (03_MeetingAbstracts): MON-594
Evaluation of the efficacy of subcutaneous administration of testosterone in female to male transexuals and hypogonadal males
FDA-approved indications for depot testosterone (T) only allow it to be administered intramuscularly (IM). Barriers to IM testosterone injections are pain/discomfort/hematoma and the frequent necessity for a nurse or other person to administer the injection which can be inconvenient and expensive. Barriers to alternative transdermal preparations are expense (often not covered by insurance), local reactions, and the fear of skin to skin transmission. Based on the personal experience of one of us (NS) and the late Jack Crawford MD with weekly subcutaneous (SC) T injections for the management of female to male (FTM) transgender patients, we have initiated a prospective study with the intent of enrolling 20 patients to assess the safety and absorption of SQ T therapy in a population of FTM individuals and classical hypogonadal males. The initial 7 patients (5 FTM and 2 hypogonadal males) ranged in age from 18-58 (mean 28.2 ± 5.9SE). T enanthate or cypionate was administered at a dose of 50-60 mg sc once weekly using 5/8″ 23g or 25g needles. Serum total T concentrations were measured by tandem mass spectrometry. T levels were well within the therapeutic range varying from 320-824 ng/dL (mean 608± 82SE). No adverse reactions at the site of injection or otherwise were reported or observed. The injections were easily self-administered except for one patient who was blind. Initial data from our study are promising regarding the SC administration of T. SC T was well tolerated and produced therapeutic serum concentrations at doses generally lower than required for IM injections. These data will provide a foundation for additional studies of pharmacokinetics, efficacy and safety to hopefully characterize SC T as a safe, convenient, and affordable alternative to IM injections.
Note from Nelson: At the doses used, half of the subjects had total testosterone blood levels under 608 ng/dL but some were able to attain TT as high as 824 ng/dL, so we are all different in our response to testosterone injections.
