While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other?
While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other?

Solution
Specific drugs affect particular receptors. Antacids and anti-allergie drugs work on different receptors. This is the reason why antacids and anti-allergic drugs do not interfere with each other’s functions, but interfere with the functions of histamines.