Carbonates (Sodium, calcium, aluminum)

Hydroxides (Aluminum, magnesium)

They neutralize stomach acid

Temporary relief of heartburn

5 to 10 mins. Depending on severity.

Average 3 hours if taken with food. 30 to 60 minutes if taken on an empty stomach.

Immediate relief.

Can be taken with other heartburn medications

Drug interactions. May decrease or increase the levels of certain drugs if taken together

Only neutralizes acid. Does not stop its production. 

Some contain sodium. Use with caution if you have to limit sodium intake.

Some can cause diarrhea or constipation.

Use antacids for immediate relief of heartburn. It does not stop acid production and heartburn will continue if not treated.

Take with food or snack to make it last longer.

Tums^® , Mylanta^® , Maalox^®  , Gelusil^® , Gaviscon^®                   

Cimetidine

Ranitidine

Famotidine

Indirectly reduce stomach acid by preventing acid pump activation.

60 to 90 minutes depending on severity. But expect symptoms to improve in 24 hours.

Up to 12 hour relief or prevention per dose

Reduces acid production. 

Use in combination with antacids in some cases.

Symptom relief may take up to 24 hours. Better to take with antacids initially to neutralize stomach acid already present while this work to reduce its production.

Most common side effect is headache.

Cimetidine (Tagamet^®), Ranitidine (Zantac^®), Famotidine (Pepcid AC^®), Nizatidine (Axid AR^®)

Omeprazole

Lansoprazole

Esomeprazole

They block acid production at the source by deactivating acid pumps in the stomach

2 to 4 days for complete relief if  first time use. Otherwise 2 to 3 hours.

24-hour relief of frequent heartburn with a daily dose. But effect can last  up to 3  days after taking it.

Stronger at preventing acid production than H2 blockers.

Increased risk of getting severe diarrhea. Must call doctor if it does not go away in a reasonable amount of time.

Taking it daily for a long period of time, a year or longer may increase your risk of fractures of the hip, wrist, spine.

Do not take if you have low  magnesium blood level.

Take 30 to 60 minutes before breakfast for maximum benefit.

Omeprazole (Prilosec^® OTC, Store brands), Lansoprazole (Prevacid 24HR^®, Store brands), Esomeprazole (Nexium 24HR^® , Store brands)       

Antacid + Gas Relief
Mylanta Gas or store brands, 

Antacid + H2 Blocker
Pepcid Complete or store brands

Antacid + PPI
Zegerid or store brands

Antacid + Pain Relievers
AlkaSeltzer or store brands

Advantage of combination use is for the antacid to neutralize acid already present in the stomach for immediate relief, while the H2 or PPI prevents further acid production.

20 to 30 mins.

Depends on combination.

Combination of immediate relief with stomach acid reduction. 

For antacid + H2 blocker combination, you cannot use more than 2 chewable tablets in 24 hours. But guess what? The antacid part only last for 4 hours. You may be tempted to chew more tablets for adequate relief.

Better to buy them separate. You can then chew antacids as often as you want to keep the stomach acid down while the H2 blocker work in the background to reduce acid production.