Tamoxifen Rifampicin

ANTIARRHYTHMICS - disopyramide, propafenone 2. ANTIBIOTICS-chloramphenicol, doxycycline, metronidazole, rifampicin, telithromycin 3. ANTICANCER AND IMMUNOMODULATING DRUGS - carmustine, cidosporin, corticosteroids, doxorubicin, etoposide, ima-tinib, lomustine, paditaxel, tacrolimus, tamoxifen, toremifene, vinca alkaloids 4. ANTICOAGULANTS - ORAL 5. ANTI-... 

TAMOXIFEN ANTIBIOTICS-RIFAMPICIN 1 plasma concentrations of tamoxifen and risk of inadequate therapeutic response Due to induction of metabolism of tamoxifen by the CYP3A isoenzymes by rifampicin Avoid concurrent use if possible. Otherwise monitor for clinical efficacy of tamoxifen by t dose of tamoxifen... 

Kauffmann, H. M., Keppler, D., Gant, T. W., and Schrenk, D. (1998) Induction of hepatic mrp2 (cmrp/cmoat) gene expression in nonhuman primates treated with rifampicin or tamoxifen. Arch. Toxicol. 72, 763-768. 

In 10 healthy men rifampicin 600 mg daily for 5 days reduced the AUC of a single 80-mg dose of tamoxifen by 86%, reduced the peak plasma levels by 55%, and reduced the half-life by 44%. Similarly, the AUC of A-demethyltamoxifen was reduced by 62%. ... 

West CML, Reeves SJ, Brough W. Additive interaction between tamoxifen and rifampicin in human biliary tract carcinoma cells. Cancer Lett (1990) 55, 159-63. 

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