Aspirin reduces effect of anti-depressants

Aspirin and other anti-inflammatory drugs taken for pain relief may reduce the effectiveness of anti-depressants such as Prozac, according to a US study.

As many as one in five people are affected by major depressive disorders but about one-third of them are resistant to anti-depressant drugs, said the study published in the Proceedings of the National Academy of Sciences.

Researchers at Rockefeller University in New York examined the most widely used type of anti-depressants, selective serotonin reuptake inhibitors or SSRIs, when taken in combination with ibuprofen, aspirin and naproxen.

Some well-known drugs in-cluded in the family of SSRIs include Prozac, Paxil, Lexapro and Zoloft.

In experiments on mice, researchers tracked brain levels of cell-signalling protein molecules called cytokines, which are boosted by SSRIs, and found they were counteracted by anti-inflammatory drugs.

Then, they analysed data collected from the largest US study on anti-depressant use in humans, the STAR*D study of 4,000 adults taken over seven years and published in 2006.

The Rockefeller researchers found that 54 per cent of patients not using pain relievers responded to anti-depressant therapy, but only 40 per cent did among those using anti-inflammatory agents.

“The mechanism underlying these effects is not yet clear. Nevertheless, our results may have profound implications for patients, given the very high treatment resistance rates for depressed individuals taking SSRIs,” said co-author Jennifer Warner-Schmidt.

The findings may have particular relevance to patients who are trying to manage both chronic pain and depression.

“Many elderly individuals suffering from depression also have arthritic or related diseases and as a consequence are taking both anti-depressant and anti-inflammatory medications,” said co-author Paul Greengard.

Our results suggest that physicians should carefully balance the advantages and disadvantages of continuing anti-inflammatory therapy in patients being treated with anti-depressant medications.”

Previous studies have suggested that anti-inflammatories may actually boost the potency of two other but less common types of anti-depressants, known as tricyclic or noradrenergic anti-depressants.