How long do Tums last once opened? Tums usually have a shelf life of around 2-3 years from their manufacturing date. Once opened, they should be stored in a cool, dry place and tightly sealed to maintain their efficacy. It is important to check the expiration date on the packaging to ensure they are safe to use. Can expired antacids cause illness? The short answer is yes, you can still take Tums after the expiration date. However, there are a few things you should know before you do. First of all, it's important to understand that the expiration date on a medication is not a hard and fast rule. Just bear in mind, says Dr. Khan, that swelling can last for a year—especially in the lower midline of the abdomen, due to gravity—and scars can take a full year to mature, so surgeons generally like to wait at least 12 months before discussing potential revisions. For most people, if you don't suffer from kidney stones or abnormal kidney function, it is safe to take tums every day for up to two weeks, as long as you stick to the recommended dosing on the Tums are a popular antacid used to relieve symptoms of indigestion and heartburn. But how long does it take for Tums to work? This guide explores the timeline of taking Tums, factors that affect its effectiveness, and tips to reduce the time it takes for Tums to start working. Tums has the benefit of working almost immediately after taking it, but unfortunately, the effects do not last long. In general, each dose of Tums lasts for 1 to 3 hours and often lasts even shorter periods of time if taken immediately after food. When you take a Tums-1 hour after eating or at the onset of gastroesophageal reflux disease symptoms-it travels directly to the source of your heartburn to buffer and neutralize the acid immediately upon contact. As it dissolves, the antacid's calcium carbonate properties continue to neutralize extra acid within the stomach and coat the x9PATG.