The study in the British Medical Journal found women with breast cancer who take both tamoxifen and the antidepressant Paxil may increase their risk of dying. Scientists say Paxil reduces tamoxifen's effectiveness.
Paxil is in a class called "selective serotonin reuptake inhibitors" that significantly inhibits an enzyme needed to metabolize tamoxifen into its active form. This effect was not seen with other SSRIs such as Celexa or Effexor.
Doctors say patients should not stop taking Paxil immediately-- but should talk with their doctors about taking a different antidepressant.