To flush or not to flush... That is the question. In a nut shell, don't flush except in certain conditions.
Essentially, the FDA and DEA say to only flush controlled substances (e.g., methadone, codeine or morphine based drugs), and prescription pain killers (e.g., percocet, percodan, vicodin) IF you have kids or pets that might get into them if disposed of in the "proper method", which is to mix uncrushed pills/capsues in with unpalatable substances, e.g., coffee grounds, cooled cooking greases, mustard, kitty litter, etc, then seal the mixture in a plastic bag and discard in regular trash.
The problem that is popping up with dropping medications down the toilet is that the pills dissolve in the water, are not filtered out of the water during standard sewage treatment practices and are discharged into downstream waterways. The residual meds in the water are then ingested by water creatures. Some meds, like antibiotics, will start acting like over-prescribed meds in humans, creating drug resistant strains of bugs that could overwhelm the natural resistances to the bugs that the aquatic organisms might naturally have. It has not been studied about how some drugs interact with non-target species, e.g., everything not human. It may affect their reproductive systems, nervous systems, etc in ways that the drugs do not affect humans. Also it has not been studied, but theorized that some drugs might be able to concentrate in some fishes with no toxic affect on aquatic organisms, but could be toxic, even deadly, to humans eating the critters. Kinda like what has happened with mercury in tuna and swordfish or DDT, chlordane, arsenic, etc in freshwater fishes such as catfish, bass, etc.
Yes, there are millions of pounds of drugs flushed into sewage systems around the nation, especially in big cities. And downstream of those major cities is where the issues w/ high levels of "XXXX" are found on aquatic organisms.
