Some patients with breast cancer who are taking tamoxifen may not get the full benefit of the drug treatment if they are also taking antidepressants, researchers said here on March 25 at the 7th European Breast Cancer Conference (EBCC7).

Recent literature has pointed to the importance of the CYP2D6 enzyme system in the activation of tamoxifen to its more active metabolite endoxifen.

In addition to some patients being poor metabolisers of tamoxifen, medications such as fluoxetine and paroxetine can lead to additional inhibition of this important enzyme and affect breast cancer therapy.

A recent study published in the American Journal of Obstetrics & Gynecology revealed that pregnant women who take selective serotonin reuptake inhibitors (SSRIs) during their second or third trimesters are five times more likely to have a premature delivery than those not taking them. Such antidepressant drugs include sertraline (Zoloft), paroxetine (Paxil), and fluoxetine (Prozac).

Researchers also found that pregnant women who take benzodiazepines, a type of psychoactive anti-anxiety drug, at any point during their pregnancies are also at a higher risk of having a premature delivery. Their babies are also more likely to be born underweight with respiratory and other health problems.

Antidepressants can help depressed patients with physical illness, and doctors should consider them more often, researchers said on Wednesday.

While around 10 percent of patients with physical diseases are thought to suffer from depression, studies suggest doctors are less likely to prescribe antidepressants because they are not sure if the medicines will work well.

The study, based on a database of more than 200,000 Quebec residents aged 65 and older, showed statistical relationships between a diagnosis of cataracts or cataract surgery and the class of drugs called selective serotonin reuptake inhibitors (SSRIs), as well as between cataracts and specific drugs within that class.

The researchers say that the study does not prove causation but only reveals an association between the use of SSRIs and the development of cataracts.

Women who take strategic serotonin reuptake inhibitor (SSRI) antidepressants during pregnancy are twice as likely to give birth prematurely as women who do not take the drugs, according to a study published in the Archives of Pediatric & Adolescent Medicine and funded by the Danish Medical Research Council.