A new study from the City of Hope has found that the commonly prescribed antidepressant drug PAXIL (paroxitene) may promote breast cancer growth.
This finding is concerning since about 25% of U.S. women in the 40’s and 50’s are prescribed medications for depression- the majority of which are in the same class of drugs (called “SSRIs” or “selective serotonin reuptake inhibitors”) as Paxil. In 2013, the U.S. FDA also approved Paxil for the treatment of menopausal-related hot flashes.
This study discovered that Paxil behaves like estrogen, which is worrisome because many cancers can be stimulated to grow in the presence of estrogen (i.e. breast, ovarian, uterine cancers, etc.) This places Paxil into a similar category of other chemicals called “endocrine-disrupters.” One of the more well-known endocrine disrupters is the chemical bisphenol-A (BPA), which also has estrogenic effects.
In 2010, a study found that breast cancer patients in Canada who were taking Paxil were more likely than those taking other antidepressants to die of breast cancer when there was a substantial overlap in their use of that antidepressant and of tamoxifen (a commonly prescribed medication used to prevent breast cancer recurrence.) At the time, the authors believed that Paxil might have had this effect by potentially blocking the production of a liver enzyme needed to metabolize tamoxifen into its active form. The authors of the current research said Paxil’s estrogenic effect “may be responsible, in part, for the observed reduction” in tamoxifen’s effectiveness in that study.
The Bottom Line:
Discuss this study with your doctor if you are taking Paxil or any of the related SSRI antidepressant drugs and you have a history of an estrogen-sensitive cancer. Don’t stop taking your SSRI without first have this conversation.
Importantly, there are other medications and non-drug therapies out there that may be as effective for treating depression and hot flashes without exposing you to an estrogen-like chemical.
As an aside, you might be shocked to know that the data actually shows the efficacy of antidepressant drugs is little better than placebo in the majority of patients taking them.
