Table 1.

Drug levels and metabolite/parent ratios before and after rifampin administration

	Blood sample
	Baseline	2-weeks post rifampin	10-weeks post rifampin
Analyte, nM (%)a
Tamoxifen	225.25	171.18 (24.0)	259.12 (0.0)
NDM-tam	386.32	177.38 (54.1)	365.66 (5.4)
4-OH-tam	6.41	2.67 (58.3)	4.29 (33.0)
Endoxifen	46.03	15.75 (65.8)	29.45 (36.0)
Metabolite/Parent ratio (%)a
NDM-tam/tamoxifen	1.715	1.036 (39.6)	1.411 (17.8)
4-OH-tam/tamoxifen	0.028	0.016 (45.1)	0.017 (41.8)
endoxifen/tamoxifen	0.204	0.092 (55.0)	0.114 (44.4)
endoxifen/NDM-tam	0.119	0.089 (25.5)	0.081 (32.4)
endoxifen/4-OH-tam	7.185	5.892 (18.0)	6.862 (4.5)

^a% reduction from baseline measurement