For occasional heartburn, you might want to take famotidine (Pepcid) at least 15 minutes before eating. But the best time to take famotidine depends on the cause of your acid reflux. Famotidine ...

King, Charles, III, Alvin J. Silk, and Ann Leamon. "Pepcid AC: Racing to the OTC Market (TN)." Harvard Business School Teaching Note 503-107, June 2003.