People on Prozac, Fish on Viagra?

The popular antidepressant fluoxetine is finding its way into our aquatic systems, where it could be harming the sex drive and sperm count of fish. How can we prevent this?

Depression is a hugely common disorder, estimated to affect between three and 17 per cent of the Canadian population at some point in their lives. It is not surprising, then, that in 2005, Canadian physicians wrote more than 12 million prescriptions for antidepressants such as Prozac (real scientific name: fluoxetine). Like most pharmaceuticals, fluoxetine is not completely processed by the body, so some of it makes its way into sewage and subsequently into nearby aquatic systems. While one might think there’s no harm in cheering up the fishies, a recent study by researchers at the University of Ottawa suggests there’s cause for concern.

The researchers were interested in determining the effects of fluoxetine, which is known to accumulate in fish, on the reproductive potential of male goldfish. They tested their research question by treating water with either a low dose of fluoxetine – similar to what may be found in the environment – or a high dose of fluoxetine (10 times more than the low dose). One group of sexually mature goldfish was exposed to the low dose in their water for 14 days, while another was exposed to the high dose. A third group, the control group, was not exposed to fluoxetine. When the 14 days were up, all three groups were stimulated with a sex pheromone. The researchers then measured a number of reproductive parameters, ranging from the volume of fish sperm to levels of various hormones in the blood.

The results of this study show that both the low and the high dose of fluoxetine impacted the reproductive potential of male goldfish. The fish exposed to either dose produced significantly less sperm following sexual stimulation than the fish that were not exposed to fluoxetine. In addition, exposure to fluoxetine led to disruptions in the reproductive hormone levels of the goldfish. Overall, the researchers were able to confirm that the reproductive systems of male fish are adversely affected by levels of fluoxetine that could exist in the environment right now.

The point of this research was not to show that Prozac can impact sperm production. We’ve already seen this in rats, and what’s more, disrupted ejaculatory responses are a side effect of Prozac in humans. What this study highlights, however, is that pharmaceutical drugs we ingest – sometimes on a daily basis – can have a lasting impact much beyond treating illnesses. We excrete these drugs into our aquatic systems, where they can have unpredictable and potentially disastrous effects, such as imbalances in the fragile equilibrium of species in the environment. This is a lesson we’re learning not only from Prozac, but also from other types of pharmaceuticals such as antibiotics. So what should we do?

Obviously, I’m not suggesting we forgo pharmaceuticals entirely. The thought of getting my wisdom teeth removed without having access to painkillers makes me shudder. Pharmaceutical drugs can treat and cure diseases and disorders, and even save lives. However, we can tackle this issue on two ends. On the prescription end, we can ensure that appropriate pharmaceuticals are prescribed for appropriate illnesses only, and that drugs aren’t over-prescribed. On the water-treatment end, we can better manage our pharmaceutical pollutants and better treat our sewage.

And what can you do to help with this issue? Take your drugs exactly as prescribed to you, and dispose of any excess in a safe manner (talk to your pharmacist!). That way, maybe we can avoid having to treat our sexually frustrated fish with Viagra.