Topical Androgen Substitution

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Traditionally, the most widely used testosterone formulations are depot injections of testosterone enantate or cipionate and oral testosterone undecanoate; less frequently used are testosterone implants or sublingual preparations and, more recently, intramuscular testosterone undecenoate. Oral testosterone undecanoate, in the usual dosage of 160–240 mg/day in 2–3 divided doses, yields low normal plasma testosterone levels with increased dihydrotestosterone (DHT) levels, whereas depot injections of testosterone 200mg (every 2 weeks) cause transient supraphysiologic testosterone levels, followed by a slow decrease to low-normal level, the fluctuations being perceived as unpleasant by the patients. Implants induce normal testosterone levels over a period of several months; however, these require surgical removal in the event of serious adverse effects, especially in elderly males. Over the last decade, several transdermal testosterone formulations delivering about 5mg of testosterone per day have become available, at first as scrotal, and later as non-scrotal transdermal patches. They have the advantage of providing physiologic testosterone levels, mimicking even normal nychthemeral variations, and of ease of stopping treatment in the event of adverse effects. The disadvantages are problems with patch adherence and local irritation. More recently, transdermal gels, containing 1–2.5% of testosterone, have come on the market. These allow for better dose flexibility, providing physiologic testosterone levels over the nycthemere. In addition, DHT gels, supposed to have less stimulating effects on the prostate, have recently become available. The most recent development is a testosterone bioadhesive buccal system, which, in a dose of 10–30 mg/day, induces physiologic testosterone levels in the majority of hypogonadal men, with minimal adverse effects. Only data concerning short-term studies are available and more experience is required before the advantages of this treatment modality can be evaluated objectively. The clinical effects of the different testosterone formulations are similar, provided physiologic levels are obtained.