Androgen use is very prevalent in society. Much of this is due to androgen abuse among athletes and bodybuilders, where black market androgen abuse has reached epidemic proportions. Indeed, in various studies of high school boys, it has been found that 4-12% had used androgens at least once. Androgens have also been prescribed for many conditions by physicians throughout the last several decades.
Despite the prevalence of legal and illegal androgen use, the science of androgen effects has greatly lagged behind the understanding of biological effects of estrogen and indications for estrogen replacement therapy. Female oral contraceptives have been in use for many years, but only recently have we seen studies regarding hormone contraceptive agents in men. Although there are a few very well-defined clinical syndromes of male hypogonadism which require androgen therapy, the use in other clinical situations, such as mild hypogonadism and hypogonadism associated with aging is less well established.
Testosterone itself cannot be given orally because in the first pass through the liver after oral administration, the breakdown is substantial and very little androgenic effects would be seen. Alkylated forms of testosterone (see table below) are much more resistant to hepatic metabolism and can exert a clinical effect when ingested. Alkylated forms of testosterone are weaker than Testosterone itself. The clinical efficacy is further complicated by irregular absorption and varying degrees of hepatic breakdown on the first pass through the liver. Therefore, varying results can be seen when giving these agents. Liver toxicity may be substantial with oral androgens, and such toxicity may range from an elevation of liver enzymes to development of hemorrhagic liver cysts. Liver neoplasms have also been reported in men undergoing oral androgen therapy. Because of these problems, oral androgen therapy has very little place in the treatment of hypogonadism.
Testosterone esters have certain advantages as injectable agents. They are relatively resistant to hepatic breakdown, are released slowly from oil-based carriers, and are hydrolyzed to yield testosterone itself. Therefore, delivery in a long-acting injection is possible, and the biological effects of the injected form of Testosterone is indistinguishable from the native hormone. The usual dosage is approximately 100mg. of drug per week is given and the interval can be varied to smooth out these wide swings, i.e. 100mg. every week, 200mg every two weeks, 300mg. every three weeks, etc. acting injection is possible, and the biological effects of the injected form of Testosterone is indistinguishable from the native hormone.
Following a testosterone injection, the serum Testosterone level rises to high normal or supranormal range for the first few days, followed by a progressive drop until the next injection is administered. The Testosterone level may drop below the normal range during this time. These wide swings may cause varying efficacy from the treatment.
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