Rebecca Tuhus-Dubrow explores what drugs do to the environment after they've gone through our system:

One of the greener drugs turns out to be that little blue pill: The human body fully converts Viagra into relatively harmless metabolites. (Well more than half of the antibiotic amoxicillin, by contrast, passes through the patient unchanged.) Such drugs offer tantalizing clues that scientists may be able to apply to future formulas.While trying to learn from these accidentally green drugs, scientists are also seeking novel ways to keep minnows off Prozac. [Retired scientist Buzz] Cue and others dream of a "magic switch" that would allow a drug to remain stable until its release into the environment, at which pointpresto!it would become biodegradable. One way to do this is to make drugs "photodegradable" with light-sensitive molecular triggers, which would cause the drug to decompose in the waste treatment plant.

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