Common Anti-Depressant Linked to Breast Cancer
Researchers have found that the common anti-depressant Paxil (paroxetine) can result in an increased risk of breast cancer development and growth.
Popular Anti-Depressant Linked to Increased Risk of Breast Cancer
According to the L.A. Times, a group of researchers from the City of Hope in Duarte has developed a quick way to identify drugs that contribute to the progression and development of diseases such as breast cancer. This method aims to identify chemicals that alter the balance of sex hormones in the body.
After screening 446 drugs that are in widespread use, the anti-depressant paroxetine was identified as having a weak estrogenic effect that has the potential to increase the rate of growth and development of breast cancer in women.
This is a matter of concern because a quarter of women that suffer from breast cancer also suffer from depression – which is usually treated with SSRIs such as paroxetine.
Researchers suspect that the drug, which is usually marketed under its commercial name Paxil, acts as an endocrine disruptor that reduces the effectiveness of medication that is meant to treat the recurrence of breast cancer.
The researchers suspect that paroxetine has the potential to block the production of a liver enzyme that is needed to metabolize tamofixen- a common drug used to prevent the recurrence of breast cancer.
Repercussions of the Paroxetine Findings
Approximately 70% of breast cancers have the potential to grow as estrogen levels in the body increase. Drugs such as tamofixen produce anti-estrogenic effects in the body to prevent the regrowth of breast cancer cells.
According to Shihuan Chen, professor and chairman of City of Hope's department of cancer biology, the connection between paroxetine and its estrogenic effects is of serious concern, as it “has implications for patients with estrogen-sensitive breast cancer who are on other medications”.
It also has implications for the quarter of women in the US aged between 40 and 50, who are currently taking anti-depressants.
It is not clear whether paroxetine inhibits the activity of estrogen directly or indirectly. However, further analysis of the drug has found that it does affect the activity of genes that respond to estrogen.
Other Drugs that Alter Hormone Levels
The study also found that the anti-fungal medications biconazole and oxcyconazole may inhibit the action of aromatase, an enzyme that converts androgen hormones into estrogen. These drugs produce similar effects of drugs that prevent breast cancer.
Furthermore, Bisephenol A, a compound used to manufacture epoxy resins and plastics was identified as a substance that could increase estrogen levels, and thus the risk of breast cancer.