Azo (phenazopyridine) does not have any drug interactions with Benadryl and they may safely be taken together.

Benadryl (Diphenhydramine)

Benadryl is classified as a "first-generation" antihistamine, which are known for their sedative properties. For this reason, it is a common ingredient in over the counter sleep aides. While generally well tolerated, it can cause dry mouth and dry eyes, as well as increase the risk of constipation with long term use.

After taking by mouth, Benadryl begins to work in 30-60 minutes and lasts around 4 to 6 hours per dose.


Azo (phenazopyridine) is a local anesthetic that works in the urinary tract, the exact mechanism with which it works is not fully known. It is commonly taken for pain, burning, and other symptoms that occur when there is irritation in the urinary tract. This medication is typically used as an adjunctive treatment for bladder infections, trauma or surgery.

It is important to keep in mind that Azo does not have any antibacterial properties and will need to be taken with an antibiotic in the case of a bladder infection. As this medication concentrates in the urine, it should not be used those with kidney impairment as it can accumulate in these patients. Azo is well known to cause a urine discoloration.


  • Benadryl can safely be taken with Azo. There is no drug interaction between the two medications.