June 4, 2023

Hi my name is caitlin chang and this is a review of the effects of fluoxetine a very commonly prescribed drug on non-target organisms and the ecosystems in which they live we all know what it is and these are probably some of the first things that come to mind you know garbage littering the beach smog polluting our air but there is one class of pollutants that

No one really thinks about and that’s these guys the pharmaceuticals they’re found in surprisingly high concentrations in our waterways making it there through our water treatment plants much of it originates from improperly disposed of hospital waste which isn’t so much a problem here in the us as in other countries people flushing their unused medications down

The toilet instead of returning them to their pharmacy and unfortunately in our urine either as metabolites or the original parent compound antidepressants are some of the most commonly prescribed medications especially now in the time of coping amongst those according to mayo clinic selective serotonin reuptake inhibitors or ssris for short are the most common

These guys aim to increase intercellular levels of serotonin a regulatory hormone that controls mood attention and appetite amongst other things by as the name implies blocking its reuptake it the synapse amongst the ssris this guy fluoxetine brand name prozac is the most prescribed and is also the most present in literature so i started my research with a very

Broad question i wanted to know what the effects of fluoxetine were on ecosystems in order to answer this i first broke it down to the level of the individual i predicted that this compound might have some anti-anxiety and appetite suppressing effects on non-target organisms due to the read across hypothesis this idea essentially states that pharmaceutical compounds

Will have the same or very similar effects on non-target organisms as long as the molecular target is conserved across species in this case we’re talking about the serotonergic system which is conserved across not just mammals but all vertebrates by that token in theory most if not all vertebrates will therefore respond to this guy serotonin in the same way that

Humans do so once again i predicted based on the read across hypothesis that fluoxetine will have anti-anxiety effects and suppress the appetite of non-target organisms because that’s what the drug does to us humans now these two things we don’t have to worry about but they can decrease fitness pretty significantly in organisms that have to survive out in the

Wild since most studies focus on the effects of fluoxetine on specific species i decided to break my research down like this i came up with a hypothetical aquatic ecosystem since once again from the first place pharmaceutical wastes end up is in the watershed in my little hypothetical ecosystem the producers are photosynthetic microbes such as algae primary

Consumers are little tiny planktonic creatures such as water fleas and the secondary consumers are teleos fishes let’s start at the bottom with the producers so fluoxetine seems to have an overall negative effect on these guys ssris as a whole have been found to have antimicrobial effects actually killing some groups of organisms while others such as algae

Only saw decreased growth smaller cell sizes and an increase in the instance of cell deformity for instance in a study on the effects of fluoxetine on algae brooks at all showed that growth significantly decreases as fluoxetine concentrations increase all of these things can be detrimental to individuals populations and ecosystems as photosynthetic activity

Or primary production is significantly decreased now a very small amount of research has been done on the effects of fluoxetine on these guys in comparison to vertebrates so mechanisms are still very poorly understood now moving on to our hypothetical primary consumers remember that these are the little tiny planktonic creatures such as the water fleas and

Midges now this group overall saw reduced growth when exposed to fluoxetine this can obviously be bad for you as an individual reducing fitness by making you more vulnerable to predators interestingly fluoxetine had various effects on fecundity or reproduction some species saw increases and others saw decreases in the number of offspring produced in the same

Study by brooks at all c dubia a type of water flea saw a significant decrease in the number of offspring reared at high fluoxetine concentrations at the same time h azteca saw an increase although it wasn’t significant now decreases in number of offspring can obviously be detrimental to species who have hundreds of them at a time so that maybe two can survive

But an increase in number of offspring isn’t necessarily a good thing either as investment per offspring would decrease with increasing numbers but once again relatively little is known on the effects of fluoxetine on invertebrates moving on to our secondary consumers remember that these are our teleos fish it’s been pretty well established that fluoxetine has

Anxiolytic effects on these guys and based on the read across hypothesis this is expected as it’s the main reason it’s prescribed to humans this has been shown in a number of behaviors first and foremost fish that were exposed to fluoxetine had a much slower reaction time in acoustic response tests which simulate danger they also spent significantly more time

Motionless as opposed to darting around the tank in a typical fishy fashion more time in the upper third of the tank as opposed to hiding at the bottom and more time in the light as opposed to hiding in the dark all of these behaviors can obviously be very bad for survival as it makes you more susceptible to predators fluoxetine also seems to have an anorectic

Effect on these fish in almost every study fish exposed to fluoxetine consumed considerably less food and the food that they did eat they took a much longer time to eat this is indicative of a decrease in appetite and was unsurprisingly accompanied by weight loss interestingly when the livers of these fish were analyzed it was discovered that fluoxetine accumulates

Here hepatocyte area was significantly decreased and less glycogen and lipids were present in the tissue this can be seen in the tissue samples to the left from defaerius at all actually from this year this one is from a fish who is exposed to high concentrations of fluoxetine you can see in comparison to the control at the bottom the cells are much closer

Together and not as shapely now decrease in appetite and weight loss are obviously detrimental to survival as it leads to this decrease in glycogen and lipids in the liver which are very important for times when food might not necessarily be available you can see now that fluoxetine has a very wide variety of effects on non-target organisms the common denominator

It decreases fitness in all of them now as you might recall my original question was on the effects of fluoxetine on ecosystems not individuals considering everything discussed here today it can be concluded that fluoxetine has the potential to drastically alter population whether it be by speciation extinction or some other means this can lead to a number

Of different things ranging from slightly different communities to total ecosystem collapse we just don’t know yet and i know this sounds all ominous and scary but this is just one tiny piece of a giant puzzle first and foremost almost none of the studies mentioned here looked at fluoxetine at environmentally relevant concentrations they were all much higher

Probably to make its effects on these organisms more apparent fluoxetine also isn’t the only pollutant floating around out there in real life an organism would be exposed to thousands of compounds all at the same time whether other pharmaceuticals or from some other source in reality we just don’t know yet both of these things warrant future studies

Transcribed from video
Fluoxetine on Nontarget Organisms; A Review By kc5921