Clinical Efficacy of the Long-Acting Intramuscular Compared to Oral Testosterone Undecanoate in Adult Men with Central Hypogonadism

Abstract

Introduction. This study evaluates the clinical efficacy of androgen replacement therapy with the new long-acting intramuscular (i.m.) testosterone undecanoate (T.U.) in comparison to oral T.U. in adult men with hypogonadotropic hypogonadism. Patients and methods. In 41 patients with central hypogonadism (30 with pituitary tumors or craniopharyngiomas, 11 with non-tumor hypogonadism), aged 20-62 years, we evaluated, before and after androgen replacement therapy, morning serum total testosterone (T), hemoglobin, hematocrit, cholesterol, triglycerides (measured with commercial kits in venous blood sampled at 8.00-9.30 a.m) and the sexual dysfunction (SD) by questions on libido, frequency and quality of erections. Results. In group A, including 28 patients treated with oral T.U. median dose 120 mg/day (range 80-160) in 3 divided doses, for 4-60 (median 14) months, T rose from 0.37 ± 0.40 ng/mL (mean ± standard deviation) to 1.43 ± 1.36 ng/mL (p<0.01), reaching normal levels only in 4 patients (14%). In group B, including 20 patients treated with 1000 mg i.m. T.U. at 12 weeks intervals, for 1-12 (median 6) months, T rose from 0.88 ± 0.83 ng/mL to 5.88 ± 3.50 ng/ml (p<0.01). T was low in 1 patient (5%) and above normal in 6 patients (30%). A subgroup (C) of 7 patients was switched from oral to i.m.T.U. T was higher after i.m. than after oral T.U in group B vs. A and within subgroup C (p < 0.01). SD improved in 7/16 patients (43.7 %) on oral T.U. and in 11/12 patients (91.6%) on i.m. T.U (p < 0.05). Hematocrit increased significantly from baseline in both groups, while serum cholesterol and triglycerides did not change significantly on either T.U. treatment. Conclusions. Clinical efficacy, judged by normal morning T and sexual dysfunction improvement, was reached in over 90% of patients with central hypogonadism after i.m.T.U. and in less than half after oral T.U.