Testosterone therapy in the hypogonadal man

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Sabine, Kliesch, MD, Department Of Urology, University Of Muenster, Muenster, Germany

Testosterone therapy in hypogonadal men is indicated if testosterone serum levels are below 10 to 12 nmol/l with clinically evident signs of androgen deficiency, such as loss of libido and potency, depression, dry skin, hot flushes, osteoporosis etc. Testosterone therapy has the aim to substitute the androgen within normal adult male ranges as physiological as possible. Natural testosterone preparations are used, applied either intramuscularly, transdermally or subcutaneously. Oral therapy with testosterone undecanoate supplies hypogonadal patients only for few hours with normal testosterone levels depending on food intake at the same time - thus biological effects are not constant and therapy is regarded ineffective. Testosterone intramuscular injection therapy is usually given in regular intervals depending on the pharmacokinetic profile of the preparation used. Testosterone enanthate must be applied every two to three weeks, while testosterone undecanoate i.m. may be applied every 3 months (up to now under investigation in clinical studies).

Subcutaneous implants are alternatives with long lasting normal testosterone serum levels, but rarely used. Transdermal patches have shown good results in studies and clinical practice resulting in normal testosterone serum levels with daily application. Skin reactions depend on the composition of the enhancers used in patches and lead to up to 30% drop out rates in patients with allergic reactions. Testosterone gels are available nowadays and show good results in clinical studies and clinical practice. Daily application leads to physiologic testosterone serum levels without serious side effects, especially with only rare allergic skin reactions.

Prior to testosterone substitution therapy contraindications must be excluded, such as existing prostate cancer or (seldom) male breast cancer. Therapy must be evaluated regularly with 3 monthly intervals in the beginning and at least 12 monthly controls thereafter. Control investigations include clinical signs of androgen deficiency and patients satisfaction, clinical examination (skin, bone, breast and prostate), laboratory parameters such as testosterone serum levels, prostate specific antigen, haemoglobin and hematocrit.