Some patients who are new users of antidepressants such as Paxil and Prozac and other selective serotonin reuptake inhibitors may run a risk of abnormal bleeding, researchers said Monday.
The problem may develop because serotonin appears to play a role in blood clotting and manipulating its levels may lead to abnormal uterine and gastrointestinal bleeding, said the report from the Utrecht Institute for Pharmaceutical Sciences in the Netherlands.
The study, which ran from 1992 to 2000, looked at 64,000 patients recently been put on the depressants, of whom 196 suffered abnormal bleeding. The patients were classified as to whether the drugs worked at high, medium or low levels as far as serotonin was involved.
“We found a significant association between degree of serotonin reuptake inhibition by antidepressants and risk of hospital admission for abnormal bleeding,” said the report published in the Archives of Internal medicine.
“Antidepressants with a high degree of inhibition of serotonin reuptake were associated with a 2.6-fold increased risk of bleeding events compared with antidepressants with a low degree of serotonin reuptake inhibition,” the report said.
The serotonin-related drugs work by providing more of that brain chemical, a substance thought to regulate depression and anxiety. The drugs are most often sold as GlaxoSmithKline’s Paxil and Eli Lilly and Co.'s Prozac.
The study did not indicate whether the bleeding problem could continue with long-term use of the drugs.
