TRANSDERMAL DIHYDROTESTOSTERONE THERAPY AND ITS EFFECTS ON PATIENTS WITH MICROPHALLUS

To investigate the efficacy of transdermal dihydrotestosterone therapy on 22 patients with microphallus, we applied dihydrotestosterone gel for 8 weeks to the external genitalia at daily doses of 12.5 mg. and 2 5 mg. for ages less than and older than 10 years, respectively. All pa tients were evaluated for penile and prostatic growth, pituitary-gonad al axis function, serum sex hormone binding globulin, lipid metabolism , hepatotoxicity, bone age and height velocity. All patients demonstra ted growth of the penis during treatment. The mean increase rate (153% ) in the first 4 weeks of treatment was higher than that (118%) of the second 4 weeks. Of importance is that responses were noted in 4 patie nts who had failed testosterone therapy for microphallus. The pituitar y-gonadal axis was transiently suppressed during treatment, and serum sex hormone binding globulin and lipid metabolism were transiently aff ected during treatment. Serum alkaline phosphatase increased, mainly d ue to change of bone isoenzyme but bone ages and mean height velocity were not significantly affected. In conclusion, transdermal dihydrotes tosterone therapy is an effective and relatively safe modality in the treatment of microphallus.