Monday, 19 January 2015

Is Quetiapine the new Valium?

One of the most striking aspects about coming to North America and witnessing psychiatric practice is the degree of polypharmacy, which is much greater than I’m familiar with. This may or may not be a bad thing but it is very different to any other setting that I’ve worked in or examined. Nowhere is this more noticeable than the prescription of quetiapine. It seems that you can’t get to see a psychiatrist unless you are already taking it. The reasons vary but it is prescribed for sleep, as an augmentation for antidepressants, to control behavioral symptoms in dementia, to treat delirium and as treatment for psychotic symptoms. There are very few psychiatric disorders it is not prescribed for. Is this just anecdote or is there some evidence for this?

Figures from the Canadian CompuScript Database show that over 2 million prescriptions for quetiapine were written in 2012 compared to 0.9 million in 2005. This increase has not been mirrored by other antipsychotics. Until 2012, Seroquel was the fifth-largest selling pharmaceutical of any kind, generating $6 billion in global sales for AstraZeneca.

Quetiapine has been approved for use in schizophrenia, bipolar disorder and major depressive disorder. It hasn’t been approved for sleep, anxiety or managing agitation in people with dementia. (In 2010, the company paid $520 million for marketing the drug off-label).

How does this compare to valium, which from the 1960’s to the 1980’s was also prescribed in large amounts often for sleep, anxiety or lesser degrees of stress. The parallels are striking. First is the initial optimism that at last there is a drug with few side effects for common difficult to treat problems. Then when problems arise the degree of adverse effects are only slowly realized. Then there are official warnings about over prescription which are widely ignored and then the law suits followed by a decrease in prescribing.

We are probably at the stage where the degree of adverse effects which include diabetes and discontinuation syndromes are just beginning to be realized. Soon there will be the law suits with some reports estimating that there are 10,000 product liability lawsuits pending against AstraZeneca for the adverse effects. Next will be guidance about reducing the prescription of quetiapine and other antipsychotics off label. Perhaps on this one we should be ahead of the curve?

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