When heartburn, gastroesophageal reflux (GERD), and gastritis don't respond to conservative treatments it's worth considering antacid medications. Most of the time these medications are optional and can be used intermittently, depending upon your symptoms.

Occasionally, several months or even years of antacid use is recommended to halt or reverse potentially dangerous changes in the lining of the stomach or esophagus. The resulting long-term reduction in stomach acid can reduce your body's ability to absorb calcium and iron. But these are rarely significant effects and can be monitored with periodic tests when necessary.

Understanding a little about how acid is produced in the stomach can help you make sense of the different types of antacids available. First, eating or feeling hungry causes histamine to be released into the bloodstream.

This is the same histamine that's responsible for allergic reactions and sinusitis, but in the stomach it triggers production of acid instead of mucus. The actual secretion of acid into the stomach cavity is accomplished by specialized parts of cell membranes called proton pumps.

As an aside, the histamine signal for stomach acid production does sometimes get crossed up with the signal for mucus production in the nose and sinuses. This can result in sneezing and runny nose when the stomach gets full, a harmless but bothersome condition called gastric rhinitis.

There are 4 different types of medications commonly used to treat excess stomach acid:

• Acid neutralizers. These substances simply neutralize any acid currently present in your stomach. They start working soon after you swallow them, but since they have no effect on acid production, the relief may only last a few hours. Acid neutralizers can be taken safely multiple times daily. Some examples are sodium bicarbonate (baking soda, Alka-Seltzer®), calcium carbonate (Tums®, Rolaids®), and blends of aluminum hydroxide and magnesium hydroxide (Maalox®). There are several other brand names, but less expensive store brands (generics) are usually equally effective. People with kidney failure should generally avoid acid neutralizers that contain aluminum or magnesium because these products rely on kidney function to remove them from the bloodstream.
  
• H2-receptor blockers. Before histamine can trigger acid production, it must first bind to a special spot on stomach cells called the histamine type 2 (or H2) receptor. This next type of antacid medication reduces histamine's ability to bind the H2 receptor, which thereby blocks the signal to make acid. These medicines don't completely shut off acid production, but they can significantly reduce it. They also don't do anything about any acid that's currently present, so it may be a few hours or even days before symptoms start to settle down. Two of the more common H2 blockers are famotidine (Pepcid®) and ranitidine (Zantac®), but there are several others. Over-the-counter versions of these medications are available in a variety of strengths. Typical dosages are famotidine 20 mg twice daily, or ranitidine 150 mg twice daily, but your doctor might recommend a different dose or schedule, depending upon your specific situation. Since people with kidney failure take longer to clear these medications from the blood, they should double the time between doses — once daily rather than twice daily.
  
• Proton pump inhibitors, or PPIs. The strongest available antacid medications work by blocking the actual proton pump, which almost completely (but not quite) turns off the secretion of acid into the stomach cavity. One of these PPIs, omeprazole (Prilosec®), which is available over-the-counter, is probably the weakest of the PPIs, but is still a very strong and effective medication. If over-the-counter omeprazole doesn't do the trick for you, about half a dozen other PPIs are available by prescription. These medications typically take the longest to start relieving symptoms — usually at least a couple of days. Dosing is typically once or twice daily, and they work best if taken a half hour or so prior to eating a meal. Like the other antacids, people with kidney failure need less frequent dosing to account for the medicine's slower removal from the body.
  
• Barriers. Sucralfate (Carafate®), available only by prescription in the U.S., works by coating the esophagus and stomach, and especially ulcers and any areas that have become damaged by acid. The coating creates a barrier that protects the damaged surface while it heals. Sucralfate should be taken 2 to 4 times daily, on an empty stomach (before meals).

If you are already using a PPI or an H2 blocker to reduce overall acid production and you are suddenly struck with acute symptoms of heartburn or gastritis, it is perfectly safe to take an acid neutralizer as needed.

Any of these antacids is actually quite safe for long-term use. But if your symptoms don't resolve after the initial 2 weeks of treatment, it's a good idea to see a physician, first to make sure there's nothing more serious going on and then to review and optimize your treatment strategy.