Tamoxifen drug interactions

Chatterjee M, Harris AL (1990) Reversal of acquired resistance to adriamycin in CHO cells by tamoxifen and 4-hydroxy tamoxifen role of drug interaction with alpha 1 acid glycoprotein. Br J Cancer 62(5) 712-717... 

The calcium channel blocker mibefradil (Posicor ) was removed from the market in 1998. The headline for the Pink Sheets article describing this action was "Posicor Withdrawal Reflects Complexity of Interaction Profile" (59). Products identified as potentially dangerous in combination with mibefradil included cardiac drugs, such as amiodarone, flecainide, and propafenone oncologic products, such as tamoxifen, cyclophosphamide, etoposide, ifosfamide, and vinblastine and the immunosuppressant medications cyclosporine and tacrolimus. The sponsor s decision to withdraw mibefradil was based on the complexity of the drug interaction information that would have to be communicated to ensure safe usage. 

The glucuronide metabolite of AZT was isolated from rat and human liver microsomal incubations (177), and the formation of a toxic metabolite of AZT was demonstrated in rat hepatocytes and liver microsomes (177). The metabolism of tamoxifen was examined in human liver homogenate and human Hep G2 cell line preparations by LC/API/MS (178). Several metabolites were detected in the human liver homogenate extracts, namely, N-didesmethyltamoxifen, a-hydroxy-tamoxifen, 4-hydroxytamoxifen, N-desmethyltamoxifen, and tamoxifen N-oxide. All of these metabolites, except the N-didesmethyltamoxifen, were observed in the samples after incubating tamoxifen with the human Hep G2 cell line. In-vitro studies have also used MS to examine potential drug-drug interactions. For example, (179) demonstrated that the a2-agonist, dexmedetomidine, inhibited metabolism of the anesthetic alfentanil, whereas clonidine had no effect. 

Ritchie LD, Grant SMT. Tamoxifen-warfarin interaction the Aberdeen hospitals drug file. BW 9Z9) 298,1253. 

Li AP, Bode C, Saikai Y (2004) A novel in vitro system, the integrated discrete multiple organ cell culture (IdMOC) system, for the evaluation of human drug toxicity comparative cytotoxicity of tamoxifen towards normal human cells from five major organs and MCF-7 adenocarcinoma breast cancer cells. Chem Biol Interact 150 129-136... 

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