Did you know when you get heartburn, it's too late to take Prilosec because Prilosec is not intended for immediate relief. But it's never too late for Zantac. Prilosec takes at least 24 hours to reach its full effect, but Zantac works differently. It relieves heartburn in as little as 30 minutes. It's fast-release acid blockers are clinically proven to relieve heartburn when it occurs. In fact, no pill relieves heartburn faster. So when heartburn strikes, try Zantac. This has been Medifacts for Zantac.