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Overview: Simethicone is used to treat the symptoms of gas, including bloating, pressure, and fullness. It works by helping gas pass more easily through your gastrointestinal (GI) tract. Simethicone is usually well tolerated, although diarrhea may occur. It is taken by mouth and is available over-the-counter (OTC) in several forms, including a chewable tablet, capsule, film, and liquid. Read and follow the instructions for the product you have and ask your health care provider if you are not sure how to take it.

Uses

What is simethicone used for?

Simethicone is commonly used to help relieve bloating, pressure, or fullness caused by gas. 

Simethicone may also be used for other conditions as determined by your health care provider.

How does simethicone work (mechanism of action)?

Gas is made by your body when you digest foods and drinks. Simethicone works by helping small gas bubbles come together. This allows gas to pass more easily through your gastrointestinal (GI) tract.

How is simethicone supplied (dosage forms)?

Brands and other names

  • Gas-X
  • Mylicon
  • Phazyme

Example dosage forms and strengths

  • 80 mg, 125 mg, 250 mg chewable tablets
  • 125 mg, 180 mg, 250 mg, 500 mg oral capsules
  • 20 mg/0.3 mL, 125 mg/5 mL oral liquid
  • 62.5 mg oral strip

How should I store simethicone?

Simethicone should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place. Protect from heat, light, and moisture. Do not refrigerate or freeze.

Side Effects

What are the most common side effects of simethicone?

Simethicone may cause diarrhea. Tell your health care provider if you have diarrhea that bothers you. 

There may be other side effects of simethicone that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of simethicone?

While less common, the most serious side effects of simethicone are described below, along with what to do if they happen.

Severe Allergic Reactions. Simethicone may cause allergic reactions, which can be serious. Stop taking simethicone and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Warnings & Precautions

Who should not use simethicone?

Allergies to Ingredients. People who are allergic to any of the following should not take simethicone.

  • Gas-X
  • Mylicon
  • Phazyme
  • Simethicone
  • Any of the ingredients in the specific product

Your pharmacist can tell you all of the ingredients in the specific simethicone products they stock.

What should I know about simethicone before using it?

Read and follow any instructions that come with the medicine.

Keep simethicone out of the reach of children.

There are several forms of simethicone available and they may need to be taken in different ways. Some products should not be crushed, cut, or chewed. Some simethicone tablets are chewable and the tablet should be chewed well before swallowing. Ask your pharmacist or other health care provider if you are not sure.

If you are taking simethicone liquid, use the oral syringe or measuring cup that comes with the medicine. A household spoon is not an accurate measuring device and may cause you to take the wrong dose. Shake simethicone liquid well before drawing up each dose. Ask your pharmacist if you do not have a measuring device or have any questions about how to take the medicine properly.

Stop taking simethicone and ask your health care provider if your symptoms continue or get worse.

What should I tell my health care provider before using simethicone?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them know if simethicone is right for you.

In particular, make sure that you discuss any of the following.

Pregnancy. It is not known if or how simethicone could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take simethicone while you are pregnant or trying to get pregnant.

Breastfeeding. Simethicone does not pass into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will let you know if you should take simethicone while breastfeeding.

Interactions

Does simethicone interact with foods or drinks?

Simethicone is usually taken as needed after meals. There are no known interactions between simethicone and foods or drinks.

There are no known interactions between simethicone and alcohol.

Does simethicone interact with other medicines (drug interactions)?

There are no known interactions between simethicone and other medicines. Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much simethicone?

If you or someone else has used too much simethicone, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of simethicone?

Simethicone is usually taken as needed for symptoms. Follow the instructions on the label of the product you are taking to make sure you take it correctly. Do not take double or extra doses.