What Are the Side Effects of Sodium Bicarbonate?

Many over-the-counter (OTC) options are available for treating heartburn. Heartburn is a painful, burning sensation in the chest and throat. It’s a symptom of acid reflux. 

Acid reflux happens when the contents of the stomach back up into the esophagus (the tube connecting the stomach to the mouth). Sometimes, frequent heartburn can be a sign of a more serious, chronic condition called gastroesophageal reflux disease (GERD). 

Antacids like sodium bicarbonate are OTC medications that can help relieve heartburn. But, even OTC medications can have side effects. Here, we’ll discuss some of the potential side effects of sodium bicarbonate and how to prevent them.

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What is sodium bicarbonate?

Sodium bicarbonate is a type of antacid. It can help relieve heartburn and an upset stomach. 

It’s available on its own or in combination with other medications. Combination products containing sodium bicarbonate include Alka-Seltzer (citric acid/aspirin/sodium bicarbonate) and Zegerid OTC (omeprazole/sodium bicarbonate). Zegerid OTC is used for heartburn that occurs at least twice a week, but it’s not intended for quick relief — it can take 1 to 4 days to work. 

Sodium bicarbonate may come as a tablet or a powder. Some tablets are dissolvable. For example, if you’re taking Alka-Seltzer, you should dissolve each dose (2 tablets) in 4 oz of water before taking it. 

Different products have different dosing instructions. Below are four example sodium bicarbonate products that are taken by mouth and instructions on how to take them. Note that we are only discussing adult doses here, but some products can also be used in children 12 years of age and older.

For most sodium bicarbonate products (but not Zegerid OTC), take the medication within 1 to 2 hours after meals with a full glass of water.

You can take sodium bicarbonate products for up to 2 weeks unless your healthcare provider has told you otherwise. After 2 weeks, contact your healthcare provider if you are still having symptoms. Together, you can discuss if it’s safe to continue using sodium bicarbonate or if another medication is needed. Your healthcare provider may do other tests to find the cause of your symptoms. 

How does sodium bicarbonate work to relieve heartburn?

Antacids like sodium bicarbonate work by neutralizing stomach acid. By lowering the acidity of your stomach, sodium bicarbonate helps relieve the pain and burning sensation from heartburn. 

Common side effects of sodium bicarbonate

Even though sodium bicarbonate is available OTC, it does have a risk of side effects. Common side effects include:

• Feeling more thirsty

• Stomach cramps 

• Gas

Serious side effects of sodium bicarbonate

Sodium bicarbonate can have more serious side effects too, but it’s rare. Some potentially serious side effects of sodium bicarbonate include:

• Severe headaches

• Loss of appetite

• Nausea or vomiting

• Irritability

• Weakness

• Urge to urinate more frequently

• Slowed breathing

• Swelling in the feet or legs

• Blood in the urine

• Bloody or black stools

If you experience any of these side effects, stop taking sodium bicarbonate and contact your healthcare provider right away.

Who should be more careful when taking sodium bicarbonate?

Products containing sodium can be more dangerous in certain groups of people. High sodium levels over time can raise your blood pressure, and affect your heart and kidneys. People with certain conditions — like high blood pressure, heart failure, or kidney disease — are more likely to experience negative effects from sodium bicarbonate. If you have any of these conditions, talk to your healthcare provider before taking sodium bicarbonate.

Sodium bicarbonate can also cause damage to your stomach if you take too much, or don’t take it correctly. Too much sodium bicarbonate can make gas form quickly in the stomach, and cause your stomach to rupture. But, this is typically avoidable if you take sodium bicarbonate correctly.

And, not all sodium bicarbonate products are recommended in children. Read the label on your product’s packaging to find out what the age cut-off is.

What can I do to manage the side effects of sodium bicarbonate?

To prevent serious side effects of sodium bicarbonate, follow these tips:

• Take the product according to the instructions on the packaging. Taking more than recommended can lead to problems, but sodium bicarbonate is typically safe if taken appropriately.

• If you’re dissolving sodium bicarbonate, make sure the tablet has fully dissolved before drinking it. This will help prevent the sodium bicarbonate from damaging your stomach.

• Don’t take sodium bicarbonate on an overly full stomach or after drinking a lot of alcohol. Sodium bicarbonate can react with food and alcohol. To be on the safe side, you don’t want your stomach full of food or alcohol when you take it. 

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Written by:

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP, has over a decade of experience as a pharmacist, professor, and researcher. She was a full-time clinical professor in the pharmacy practice department at D’Youville School of Pharmacy before subsequently joining the faculty of the pharmacy practice department at the University at Buffalo School of Pharmacy and Pharmaceutical Sciences.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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