Question

You have an infection, and you see that the physician is about to inject you with millions of units of penicillin. What do you think will happen to your urine production as a result?

Answer 1

Penicillin is excreted in urine in its fully functional form (40-99%) in urine 4 hrs post administration. They are excreted by glomerular filtration and tubular extraction from kidneys. Tubular secretory mechanism is the main mechanism involved in penicillin excretion. Urine will have the smell associated with penicillin. Generally, penicillin that is secreted does not affect the kidneys. However, in some cases, it may cause nephrotoxicity, especially in high doses.

In case of Ampicillin (a form of penicillin), urea clearance and creatinine clearance reduce below normal. It may cause interstitial nephritis, which is inflammation of the spaces between kidney tubule. Glomerulonephritis is also common with penicillin. Methicillin can induce more nephrotoxicity than other penicillin. A reduced urine output and BUN value may result in discontinuation of penicillin as treatment measure for patients.

Thus, high doses of penicillin may cause reduction in urine output.