Effects of anastrozole on the cytochrome P450 activities in human liver microsomes
| CYP | Marker Substrate | Test Substance | IC50(μM)1-a | Ki (μM) |
|---|---|---|---|---|
| 1A2 | Phenacetin | Anastrozole | 30 | 8/80 |
| 2A6 | Coumarin | Anastrozole | >5001-b | — |
| 2C9 | Tolbutamide | Anastrozole | 48 | 10 |
| 2D6 | Dextromethorphan | Anastrozole | >5001-b | — |
| 3A | Nifedipine | Anastrozole | 27 | 10/55 |
| 3A | Nifedipine | Triazole | >2501-b | — |
| 3A | Nifedipine | BMPN-benzoic acid | >2501-b | — |
| 3A | Nifedipine | Ketoconazole | 0.02 | — |
| 3A | Nifedipine | Cimetidine | 650 | — |
↵1-a IC50 values were determined using the following concentrations of the specific CYP-marker substrates: phenacetin, 100 μM; coumarin, 50 μM; tolbutamide, 1 mM; dextromethorphan, 100 μM; nifedipine, 25 μM.
↵1-b Anastrozole and its metabolites (products formed by N-dealkylation) were not tested for CYP inhibition above 250–500 μM. Because little inhibition was observed at high concentrations, Ki values were not determined.