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DYK: Penicillin used to be recycled from urine

If your urine smells funny while taking antibiotics it could be that some of the medicine is being excreted in your pee. Once upon a time it would have been collected and reused!

After Alexander Fleming’s 1928 discovery of a mold that inhibited Staphylococci bacteria growth and the first treatment of a patient with penicillin in 1942, demand for this antibiotic grew rapidly. Unfortunately, due to the difficulties of growing molds and isolating the penicillin molecules from them, the medication was extremely difficult to produce in large scale.

One way to combat the shortage of penicillin was to collect the urine of patients taking it and extract the antibiotics found there. Benzylpenicillin (also called penicillin G) has a bioavailability of only around 30%, which means that 70% of the dose you take is excreted in your urine. Scientists found that they could isolate those molecules from a patient’s urine, purify them, and then use them to treat other patients with bacterial infections. While perhaps unappetizing, this method undoubtedly saved many lives. Penicillin was responsible for lowering the death rate from bacterial pneumonia from 18% during World War I to less than 1% during World War II.

Luckily with the discovery of a different species of penicillin producing fungus on a cantaloupe, as well as improvements in fungus culturing techniques and strategic mutations, penicillin became much easier to produce. Modern penicillin antibiotics have also been developed that are much more bio-available than their early counterparts. In the case of the commonly used amoxicillin, oral bioavailability is roughly 95%.

So, if you ever notice your urine smelling a bit funny while taking a course of antibiotics, don’t worry too much. Either some antibiotic is being excreted in your pee, making it stink, or you may have just eaten a lot of asparagus.


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