If your urine smells funny while you are taking antibiotics, some of the medicine may be excreted into your pee. Once upon a time, it was collected and reused!
After Alexander Fleming discovered a mould in 1928 that inhibited the growth of staphylococci bacteria, and the first treatment of a patient with penicillin in 1942, the demand for this antibiotic increased rapidly. Unfortunately, due to the difficulty of growing moulds and isolating the penicillin molecules from them, it was extremely difficult to produce the drug on a large scale.
One way to combat the penicillin deficiency was to collect the patients’ urine and extract the antibiotics found there. Benzylpenicillin (also called penicillin G) has a bioavailability of only about 30%, which means that 70% of the dose you take is excreted in your urine. Scientists have found that they can isolate these molecules from a patient’s urine, purify them, and then use them to treat other patients with bacterial infections. Although this method may be unappetizing, it has undoubtedly saved many lives. Penicillin was responsible for reducing the mortality rate from bacterial pneumonia from 18% during World War I to less than 1% during World War II.
Fortunately, penicillin became much easier to produce through the discovery of a different type of penicillin-producing fungus on a melon and improvements in mushroom growing techniques and strategic mutations. Modern penicillin antibiotics have also been developed that are much more bioavailable than their early counterparts. In the case of the commonly used amoxicillin, oral bioavailability is approximately 95%.
So if you ever notice that your urine smells a bit funny during an antibiotic treatment, don’t worry. Either an antibiotic is secreted into your pee, making it stinky, or you’ve just eaten a lot of asparagus.