Schizophrenia Drugs May Up Tumor Risk
A statistical "signal" links Risperdal and other schizophrenia drugs to pituitary tumors, FDA researchers report.
May 31, 2006 – A statistical "signal" links Risperdal and other schizophrenia drugs to pituitary tumors, FDA researchers report.
The finding is not proof that these extremely useful drugs cause these benign (noncancerous) tumors. And it does not tell how often patients develop drug-linked pituitary tumors, says Duke University psychiatrist P. Murali Doraiswamy, MD. Doraiswamy was a member of the research team led by the FDA's Ana Szarfman, MD.
The researchers used a highly sophisticated computer program to analyze the FDA's database of 40 million combinations of drugs and side effects reported by doctors and patients. They found 77 reports of pituitary tumors in patients using seven different antipsychotic drugs. Seventy percent of these reports were in patients taking Risperdal.
"When you put all the data together, you get a strong biochemical plausibility that this is a Risperdal effect," Doraiswamy tells WebMD. "But we cannot rule out the possibility it is a spurious association. No one should stop Risperdal because of this. Even if Risperdal is linked to pituitary tumors, it may turn out to be fairly rare."
Szarfman, Doraiswamy, and colleagues report the findings in the June 2 issue of the journal Pharmacotherapy.
Small Risk, Benign Tumors
The tumors linked to Risperdal and other drugs are not necessarily dangerous. Many are microscopic. Few are larger than 1 millimeter.
"These are benign tumors, better thought of as a cyst," Doraiswamy says. "They grow slowly and, generally, locally. Most are very tiny. But sometimes they grow, and when they do, they press on surrounding tissue and cause hormonal problems. Or they can press on the optic nerve and cause some loss of vision."
Janssen, the Johnson & Johnson subsidiary that makes Risperdal, is already telling patients about animal studies and human case reports that link antipsychotic drugs to pituitary tumors, or, as doctors call them, adenomas.
"Last year, we updated our labeling to ensure that health care professionals are aware of reports of benign pituitary adenomas in patients using antipsychotic medications," Janssen spokeswoman Theresa Gaines tells WebMD. "Benign pituitary adenomas are present in 10% to 25% of the general healthy population."