Table 2. The distributions of concentrations of tamoxifen and its metabolites in 550 plasma specimens of 281 patients.
| Variables | Concentrations (95% CI) in ng/mL | |||||||
|---|---|---|---|---|---|---|---|---|
| Endoxifen | NDM | Tam | 4-OH Tam | Endoxifen /NDM | Endoxifen /4-OH Tam | NDM /Tam | 4-OH Tam /Tam | |
| Mean | 25.0 (24.2-25.8) |
230 (221-240) |
128 (124-133) |
8.53 (8.26-8.80) |
0.13 (0.12-0.14) |
4.27 (3.29-5.25) |
1.83 (1.78-1.87) |
0.08 (0.07-0.08) |
| SD | 9.47 | 108 | 54.5 | 3.21 | 0.09 | 11.7 | 0.54 | 0.04 |
| CV | 38% | 47% | 43% | 38% | 69% | 274% | 30% | 50% |
| 5th percentile | 12.5 (11.4-13.6) |
80.5 (71.5-92.8) |
50.3 (44.6-56.0) |
2.60 (2.00-3.40) |
0.05 (0.05-0.05) |
1.82 (1.74-1.86) |
1.18 (1.12-1.24) |
0.02 (0.01-0.02) |
| 25th percentile | 18.5 (17.7-19.4) |
157 (145-168) |
89.4 (83.5-95.2) |
6.70 (6.20-7.20) |
0.08 (0.08-0.08) |
2.37 (2.30-2.45) |
1.51 (1.48-1.58) |
0.05 (0.05-0.06) |
| 50th percentile | 23.4 (22.5-24.4) |
223 (215-231) |
123 (117-129) |
8.75 (8.50-9.00) |
0.11 (0.10-0.11) |
2.82 (2.76-2.87) |
1.79 (1.74-1.82) |
0.08 (0.07-0.08) |
| 75th percentile | 30.2 (29.1-31.2) |
282 (271-298) |
158 (153-165) |
10.4 (10.1-10.7) |
0.15 (0.14-0.17) |
3.45 (3.33-3.62) |
2.08 (2.03-2.14) |
0.10 (0.09-0.10) |
| 95th percentile | 42.7 (40.1-44.8) |
413 (380-438) |
231 (218-245) |
13.4 (12.9-14.4) |
0.29 (0.26-0.33) |
7.18 (5.40-9.05) |
2.53 (2.45-2.69) |
0.14 (0.13-0.15) |
CI, confidence interval; CV, coefficient of variation; NDM, N-desmethyltamoxifen; 4-OH Tam, 4-hydroxytamoxifen; SD, standard deviation; Tam, tamoxifen.