A pharmacist is trying to study the effect of tamoxifen on treatment of patient with recurrent breast cancer. He also detects that the serum level of the active tamoxifen metabolites are low between the relapsed patients. Which of the following is the most likely cause of the drug's ineffectiveness in this subset of patients?

Question

Quizplus · Accepted Answer

Eductional Objective: Cytochrome P450 enzymes found in the liver are responsible for the majority of drug metabolism.  Polymorphisms occurring in the genes coding for these enzymes result in various phenotypes that differ in their rates of metabolism; individual differences in phenotype alter treatment efficacy and drug toxicity.

A Pharmacist Is Trying to Study the Effect of Tamoxifen