Prozac on the loose?

The UK Environment Agency is asking manufacturers of the antidepressant fluoxetine to look at whether the chemical is finding its way into the environment and having an effect on wildlife.

Fluoxetine hydrochloride was first introduced in 1988 by Lilly and Company and marketed under the trade name ‘Prozac’. Since the patent expired in 2000, the compound has been marketed in the UK by a number of other companies. Last year, doctors in the UK issued over 5 million prescriptions for fluoxetine – equating to around 4.1 tonnes of the compound.

Research suggests that once fluoxetine is in the environment it is not easily broken down. It can also be toxic to aquatic life at low concentrations. Up to now, however, because of the lack of effective analytical methods, there has been no monitoring for fluoxetine or its major breakdown product norfluoxetine in the UK environment.

The UK Environment Agency, however, is now doing work to develop and trial methods that will allow the levels of these chemicals in river water and sewage effluent to be measured.

The Agency is calling on the pharmaceutical industry to assist in environmental monitoring, and to undertake further research on the toxicity of fluoxetine to aquatic life.

Derek Tinsley, the Environment Agency’s Head of Air and Chemicals Policy said: “When people take pharmaceuticals like fluoxetine, small quantities can be excreted. This, and the disposal of unwanted medicines down household drains, creates the potential for these substances and their breakdown products to enter sewage works and rivers. Although our sewage treatment plants remove most of these products, small quantities can remain in the effluent that is returned to the rivers and seas. We don’t know how much fluoxetine is finding its way into the environment. What we do know is that it’s a widely used substance, its toxic to aquatic life at low concentrations, and once in the environment it persists for quite a while.”

“Previous research backed up by our own initial calculations suggests that fluoxetine will not be at levels in our rivers high enough to kill aquatic life.However, we are unclear about the longer term and subtle impacts (such as effects on reproduction and growth) that very low but continuous concentrations might have on our aquatic species,” he said.

“That’s why we are asking the manufacturers to undertake some research, so that we can make judgements about risk to the aquatic environment based upon sound science,” he added.

The Environment Agency is asking the manufacturers of fluoxetine to assist in monitoring the levels of fluoxetine and norfluoxetine present in rivers and sewage works effluents in England and Wales, and, if these substances are found to be entering the aquatic environment in England and Wales, then to carry out research to assess whether the concentrations are capable of affecting aquatic life.

Last year, incorrect reports that the Environment Agency had found traces of fluoxetine in rivers, groundwater and drinking water surfaced in the media. At the time of the reports, no monitoring for fluoxetine had been undertaken. The Drinking Water Inspectorate is responsible for monitoring drinking water quality. The Inspectorate is confident that, because of the sophisticated water treatment systems in place, fluoxetine would not be detected in the public water supply.