Nitrofurazon, opinions and questions

Good morning, Today the pediatrician prescribed her son (7years) Deteromycin 2% - a bacterium was detected in the urine and the son has a very reddened area around the urethra. Reading the leaflet I noticed that it is a drug for people 18+, quite strongly affecting the body and as it turned out, once he already had one prescribed (I admit that I did not read the leaflet then), and in one of the points there is information that repeated treatment with a drug containing chloramphenicol should be avoided. Tomorrow I will call the pediatrician and explain it, but I would like to advise you to have any idea if there is any over-the-counter drug (or prescription - I will ask about it at the visit) that can help in this case? I know that some drugs react with each other, so I will add that the son takes Euthyrox25 and Medikinet CR10. Thank you in advance for the hint.