Serum estradiol and danazol. I. Endometriosis response, side effects, administration interval, concurrent spironolactone and dexamethasone.

Serum estradiol (E2) levels and resolution of endometriosis were evaluated in 42 women after 75 days of danazol treatment. Complete or almost complete remission occurred when radioimmunoassay E2 levels were less than 15 pg/ml in extensive, less than 22 pg/ml in severe, and less than 41 pg/ml in moderate endometriosis. E2 less than or equal to 20 pg/ml occurred in 23% of 104 patients given 400 mg every 12 hours but in none weighing over 150 pounds (68 kg). E2 greater than 100 pg/ml occurred in 7%. The mean E2 levels were identical with 400 mg every 12 hours and 200 mg every 8 hours. The E2 level was 40% lower with 200 mg every 6 hours than with 400 mg every 12 hours (P less than 0.001). Dexamethasone further decreased E2 levels by 61% (P less than 0.001). Spironolactone decreased androgen symptoms but increased E2 levels by 49% (P less than 0.01).