Free testosterone levels during danazol therapy

Dosage‐related Effects of Danazol on Sex Hormone Binding Globulin and Free and Total Androgen Levels

“…We have previously suggested that the androgenic activity of danazol in v i m may be at least partly dependent on its suppression of plasma sex hormone binding globulin (SHBG) levels (Bevan et al, 1984) which would be expected to result in an increase in the free, biologically active testosterone concentration. We have further confirmed that the percent free testosterone is significantly increased by danazol treatment (Dowsett et al, 19861, but total testosterone concentrations have been reported as decreased by some authors (Nilsson et al, 1983;Carlstrom et al. 1983Carlstrom et al.…”

“…The overall effect was to double the free concentration during the first week but thereafter levels fell back to only about 25-50% above pretreatment levels. Nilsson et al (1983) reported that free testosterone levels rose from a mean 25 pmol/l to 45 pmol/l after 2 to 3 months' treatment with 600 mg danazol daily. The higher level of free testosterone during treatment in that study may result from the lack of consideration of possible cross-reaction of metabolites in their testosterone assay; it is notable that the total testosterone concentration was not significantly reduced, which is in marked contrast to the present study.…”

“…The higher level of free testosterone during treatment in that study may result from the lack of consideration of possible cross-reaction of metabolites in their testosterone assay; it is notable that the total testosterone concentration was not significantly reduced, which is in marked contrast to the present study. Furthermore, Nilsson et al (1983) calculated rather than measured the percent free testosterone, and in that calculation no account is taken of the competitive effects of ethisterone on SHBG binding sites. More recently Nilsson et al (1986) have reported a mean increase in salivary testosterone on danazol-treated patients of about 3o' YO which is more compatible with our observations on free testosterone concentration.…”

Binding of Levonorgestrel, Norethisterone and Desogestrel to Human Sex Hormone Binding Globulin and Influence on Free Testosterone Levels

“…The KA values for albumin binding were assumed to be the same as for testosterone. Normal values of testosterone (2 nmol/1) and albumin (7.2 X 10~4 mol/1) as previously determined [12] and literature data on serum concentra tions of levonorgestrel, norethisterone and 3-keto-deso gestrel during clinical treatment [13][14][15][16] were used in a computer program to calculate free, SHBG-bound and albumin-bound amounts of testosterone [11]. Calcula tions were performed for three different serum concen trations of SHBG (40, 70 and 140 nmol/1) within the normal range during clinical treatment [12], The in fluence of oral administration of 150 pg of levonorges trel, 150 pg of desogestrel, 0.5 and 5 mg of norethis terone, as calculated from peak serum concentrations, on the distribution of testosterone between protein-bound and free fractions is given in table 1.…”

Goserelin (Zoladex) versus danazol for endometriosis: the North American experience

“…Danazol binds to sex hormone‐binding globulin, displacing testosterone. This results in an increase in free testosterone from 1% in untreated women to 2% in women treated with danazol 8 . The overall effect is a combined high androgen–low oestrogen environment, which results in eventual atrophy of endometriotic implants and reduction in severity of symptoms.…”