Hi..my Son Is 5 Yrs Old. He Is On Syp

hi..my son is 5 yrs old. he is on syp mox 5ml twice a day, syp ibugesic plus 5 ml thrice a day by his dentist as he is undergoing root canal treatment. on the second day of taking his medication his urine becoame dark brown red in colour.however my son was absolutely normal while eating playing sleeping. he had no fever or pain. when I stopped all the medicines his urine turned normal in colour within 24hts of stopping the medicine. y did this
happen and is this harmful for the kidneys?