The provider will order to discontinue the use of diphenhydramine tablet if it is concurrently given with ipratropium bromide tablet because it can increase adrenaline effects on the heart rate and blood pressure of a patient. It has also an anticholinergic effect that may cause blurred vision, increased saliva, heat intolerance, fever, and increased bowel movements and urination.
Moreover, the physician can also prescribed ipratropium nasal for it has poor systemic absorption where interaction with diphenhydramine would be unlikely at regularly recommended dosages.