Schizophrenia Drugs May Up Tumor Risk
A statistical "signal" links Risperdal and other schizophrenia drugs to pituitary tumors, FDA researchers report.
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Small Risk, Benign Tumors continued...
Expensive MRI scans are the only way to detect a pituitary tumor. It may be
that these tumors are seen in patients taking Risperdal because that is where
doctors are looking, says Glenn W. Currier, MD, medical director for psychiatry
at the University of Rochester, N.Y. Currier is not affiliated with Janssen but
has been lead researcher in Janssen-funded clinical trials and has served on
Janssen's Risperdal speakers' board.
"Are we finding these tumors in Risperdal patients because we wouldn't
be looking for it if they weren't taking the drug?" Currier asks.
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Sexual Symptoms May Warn of Tumor Risk
The pituitary gland is a small organ in the center of the brain. It secretes
hormones that have direct actions on the body, and/or regulate other hormones
in your body.
How could schizophrenia
drugs cause pituitary tumors? The pituitary gland makes a hormone called
prolactin. Prolactin tells women's breasts to enlarge and make milk. Normally,
a brain chemical called dopamine puts the brakes on prolactin production.
Risperdal and several other antipsychotic drugs block dopamine. This reduces
their psychotic symptoms -- but it also takes the brakes off the pituitary's
prolactin machinery. Overproduction of prolactin, over time, can make the
pituitary grow larger, which ups the risk for tumor growth.
"A quarter of all patients who take Risperdal have prolactin
elevations," Doraiswamy says. "Most are mild and fairly transient, so
those people don't need to worry at all. Many, many people have taken Risperdal
for years without any problem. But Risperdal is far more likely to cause
prolactin problems than many other drugs in its class."
Those who do have problems, Doraiswamy says, usually have sexual symptoms:
male impotence, breast
tenderness, breast enlargement, and/or abnormal milk secretion in a child, a
man, or a nonpregnant woman.
"We just had a call from a patient who had a pituitary tumor while on
Risperdal, and then switched to another drug and the tumor went away,"
Doraiswamy says. "But if any drug switching is done, it must be done with a
psychiatrist's care. If you suddenly switch from one drug to another, psychotic
symptoms may flare up."