Doctors relaxed over study into Prozac, cancer link

Doctors and mental health groups are urging patients on drugs such as Prozac to keep taking their medication despite a British study linking it to an increased risk of cancer.

Laboratory research has shown that Prozac and similar antidepressants stimulate the growth of tumours by blocking the body's natural ability to kill cancer cells.

More than 600,000 prescriptions for antidepressants are given every year in New Zealand.

Professor John Gordon of Birmingham University told the Scotsman newspaper that in test-tube experiments, Prozac and other selective serotonin re-uptake inhibitors (SSRIs), encouraged growth of a type of cancer called Burkitt's lymphoma.

Serotonin is a naturally occurring chemical that regulates moods. People with too little often suffer depression.

Drugs such as Prozac work by preventing serotonin from being reabsorbed too quickly by nerve cells in the brain. But the study found that serotonin was a key driver in stimulating a natural cell "suicide" process for controlling the runaway growth that leads to cancer.

The antidepressants prevented serotonin from being absorbed into the cancer cells, leading to a more vigorous growth of the tumours.

New Zealand Medical Association chairman John Adams, who is also a psychiatrist, said people should not stop taking their medication because of a limited study.

"People need to keep taking their medication because stopping ... increases the danger of dysfunction and, in severe cases, suicide."

Dr Adams said Prozac and similar drugs were effective, safe and had limited side-effects.

Health Ministry spokesman Stewart Jessamine said the study was a "preliminary piece of research on which we should not be basing any clinical decisions".

- NZPA

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