Thanks for the query.
I understand your concern.
Better to take any medicine after consulting your doctor and with proper diagnosis.
Usually in case of urinary tract infections, urine for microscopy and culture and sensitivity are advised to find out the causative organism and its sensitivity to drugs.
Then medicines should be used accordingly.
If you are using Macrobid antibiotics with your doctor's advice, you can take it after around 6 to 8 hours after taking methenamine as there are no known drug interactions between these two.
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.