Short-Term Effects of Intramuscular and Transdermal Testosterone on Bone Turnover, Prostate Symptoms, Cholesterol, and Hematocrit in Men Over Age 70 with Low Testosterone Levels

Abstract

The objective of the study was to determine whether short-term testosterone administration to older men with low bioavailable testosterone would have any immediate adverse effects, especially on the symptoms of benign prostate hyperplasia, preliminary to embarking on a long-term study of testosterone treatment. Transdermal and intramuscular testosterone were compared to determine whether there were any rapid changes in markers of bone formation or resorption with either testosterone administration. We undertook a non-randomized trial of 9 weeks intervention with either intramuscular testosterone, transdermal testosterone or neither followed by a 9-week observation period. Twenty-seven men over age 70 years with no medical conditions known to affect bone turnover and total testosterone levels below 350 ng/dl (normal range 350–1230 ng/dl) or bioavailable testosterone levels below 128 ng/dl (normal range 128–430 ng/dl) received either testosterone via transdermal patch (TP; two 2.5 mg patches/d), intramuscular testosterone enanthate (IM; 200 mg every 3 weeks) or no testosterone for 9 weeks of treatment followed by a 9 week observation period. Nine men were enrolled in each group. The mean age of the men was 74 ± 3 years (range 70–83 years). While all men receiving testosterone treatment increased levels above their own baseline, only 6 of 9 men receiving transdermal testosterone achieved bioavailable testosterone levels in the normal range for young men. Neither treatment group demonstrated changes in estradiol levels. No side effects were reported using the intramuscular testosterone while 5/9 men using transdermal testosterone developed a rash. There were no significant changes in markers of bone resorption or formation in either testosterone treatment group. There were no ill effects on prostate size, symptoms or prostate specific antigen level. PSA levels of 1.5 ± 0.7 ng/dl and 1.6 ± 0.7 ng/dl in the TP and IM groups, respectively, were 2.0 ± 1.0 ng/dl and 1.8 ± 0.9 ng/dl following treatment. Cholesterol profiles were also not affected by either transdermal or intramuscular testosterone. Similarly hemoglobin and hematocrit remained unchanged in men receiving either testosterone preparation.