Zantac 360 Maximum Strength Antacid is a powerful heartburn remedy formulated for both prevention and relief. This H2 blocker (histamine 2 blocker) quickly reduces stomach acid production, preventing heartburn when taken just 10 minutes before eating or drinking. It also provides fast relief for existing heartburn symptoms when taken after a meal. Zantac 360 Maximum Strength boasts a triple-action formula that allows you to enjoy meals without compromise: preventing heartburn beforehand, relieving existing symptoms quickly, and offering long-lasting relief for up to 12 hours (referring to acid control, not necessarily symptom relief).