Thank you for your query at DoctorSpring.com
I understand your concerns.
I need to know the names of the medicines you took before commenting. The only medicine that can turn urine red is Nitrofurantoin, but that is an antibiotic. Also, I will still suggest you to get an urine culture done, because infections can't be treated with OTC drugs. It can rather ascend up and cause further problems.
Hope you understand,