Antipsychotics tumour link

June 2, 2006
by Angela Hussain

Antipsychotic drugs may cause benign tumours in the pituitary gland, according to research published today.

Researchers found that seven antipsychotics were "associated" with the development of pituitary tumours that were reported to the US drugs regulatory body, the Food and Drug Administration (FDA), which monitors drug side effects. But risperidone was linked the most - on 70 per cent of instances - to such tumours

The findings are in a research paper in the Pharmacotherapy journal, published today.

In the United States, risperidone - trade name risperdal - is the most widely-prescribed atypical antipsychotic. Also widely used in the UK, it is prescribed to people diagnosed with schizophrenia and manic-depressive disorders.

The paper's authors cautioned, however, that their study does not prove antipsychotics cause pituitary tumours.

"Our findings do not prove a causal relationship between antipsychotic medications and pituitary tumors, but health professionals and patients should be aware of such potentially adverse effects," said co-author Murali Doraiswamy, a psychiatrist in the department of psychiatry and medicine at Duke University Medical Center in North Carolina.

"Atypical antipsychotics are lifesaving medications for a lot of people," he added. "By no means are we advocating that people stop using them, especially risperidone," he said.

The researchers assessed six atypical antipsychotics and one typical antipsychotics using a "data mining" analysis of the FDA's Adverse Event Reporting System database.

The researchers looked for disproportionate reporting patterns of pituitary tumors linked to use of risperidone, aripiprazole, clozapine, olanzapine, quetiapine, ziprasidone and haloperidol, the typical antipsychotic.

They found 77 reports of pituitary tumors associated with the seven antipsychotics. Risperidone was associated with 54 (70 per cent) of those reports.

The researchers said they were concerned that development of pituitary tumors following chronic use of potent antipsychotics can lead to other health problems.

"We worry that symptoms may not be evaluated quickly enough, which, if due to a tumour, could lead to complications such as visual problems or localized bleeding near the pituitary gland," Doraiswamy said.

See also:
May 19, 2006: End “routine” prescribing of high-dose antipsychotics - "possible link" of antipsychotics with sudden death, states report

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Scare-mongering

Comment from: Ben Clark, SHO Psychiatry, South London and Maudsley NHS Trust, London.
Date: July 10, 2006

How much scare-mongering is in this story? The study reported mined data, looking for posssible adverse drug reactions reported to the FDA, rather than a case-control study which could calculate odds ratios and risks of exposure.

Association does not imply causation, as the first paragraph suggests. Even if it did, do we think it would be likely to be dose-related? (probably, and therefore relevant since prescribing practices in the States are quite different to the UK).

Risperidone accounts for 70% of the reported tumours, but is this because risperdal is more commonly prescribed? This study creates a lot more questions which need to be addressed, but reporting it in this way only adds to unjustified anxiety for every patient and semi-informed relative who is now convinced their poor schizophrenic relation is going to get brain cancer.

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