Worried. I am on Macrobid for two more days. I took Zantac tonight because I had crazy, severe…

Worried. I am on Macrobid for two more days. I took Zantac tonight because I had crazy, severe heartburn. I just now read on the pamphlet for the Macrobid not to take any antacids that contain magnesium trisilicate (I think thats how it was spelled) and I dont know if Zantac has it. I took the Zantac about two hours ago, but right now its time for my Macrobid. Anyone know if the two are safe to take within two hours of each other?