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Abstract

Androgen substitution in men

Hypogonadism as a condition of testosterone (T) deficiency requires substitution therapy. However, a generally accepted definition of this clinical entity does not exist. It has not been completely investigated to which extent the incidence and the symptoms of hypogonadism increase with advancing age. Especially in older men, a decreased Leydig cell capacity as well as an altered hypothalamicpituitary responsiveness can facilitate an androgen deficiency. It is likely that this process is augmented by visceral adipose tissue, i.e. in most cases the metabolic syndrome. Regardless of age, serum T levels below 12 nmol/l, accompanied by symptoms of androgen deficiency, are regarded as an indication for T substitution therapy, provided a prostate carcinoma has been excluded. Injectable T enanthate or cypionate provide serum T levels above the lower limit of normal for 2 to 3 weeks. Longer acting T esters, allowing injection intervals of 10 to 14 weeks are a feasible treatment option (injectable testosterone undecanoate). While these esters will be most useful for substitution of younger hypogonadal men, in older men shorter acting preparations are preferable: they can be easily withdrawn if therapy needs to be quickly terminated due to unwanted effects (e.g. polycythemia) or interfering diseases (e.g. prostate carcinoma). Oral or transdermal T preparations are thus recommended in elderly men. Particularly transdermal T has the advantage of mimicking serum T levels corresponding to the physiological circadian rhythm. In any case, natural testosterone should be used which can be aromatized so that estrogen-dependent functions (e.g. in bone metabolism) can be maintained.

CME Prakt Fortbild Gynakol Geburtsmed Gynakol Endokrinol 2016; 12(3): 188–199

Keywords
Male hypogonadism, aging male, testosterone substitution, pharmacokinetics, side-effects

Michael Zitzmann
Centrum für Reproduktionsmedizin und Andrologie, Universitätsklinikum
Münster der Westfälischen Wilhelms-Universität Münster
Reviewer: Armin Heufelder, München,
und Ulrich A. Knuth, Hamburg

Zitzmann M. Androgensubstitution ... Gynakol Geburtsmed Gynakol Endokrinol 2016; 12(3): 188–199 publiziert 30.11.2016 www.akademos.de/gyn ©akademos Wissenschaftsverlag 2016 ISSN 1614-8533