Clinical evaluation of long-term treatment with levo-norgestrel and testosterone enanthate in normal men.

Thirteen healthy men (25-35 years) with proven fertility were scheduled for long-term treatment (> 12 months) with levo-norgestrel (500 micrograms daily) and testosterone enanthate (200 mg monthly). The volunteers were regularly investigated prior to, during and after treatment. Seven volunteers withdrew from medication after 1 to 12 months of treatment; three due to psychological side effects, one because of stiffness of a finger joint, two for personal reasons and one for unspecified reasons. Sperm counts were significantly decreased during treatment and in 7 volunteers the sperm counts were < 5 x 10(6)/ml. However, two of these volunteers exhibited a breakthrough in sperm counts after 12 and 13 months of a 16-month treatment period. Serum testosterone, serum LH and serum FSH were significantly decreased during treatment, but returned, as did sperm counts, to normal levels after withdrawal of treatment. No rebound effect was seen. Potency and libido remained unchanged. No toxicological side effects were observed and finally no consistent changes were seen in blood coagulation parameters.