Generic Name: simethicone

Brand Names: Mylicon, Phazyme, Gas X Extra Strength, Gas X Softgels, Gas X Thin Strips, Children’s Gas X Tongue Twisters Thin Strips, Gas X, PediaCare Infant’s Gas Relief Drops, St. Joseph Infant’s Gas Relief

Drug Class: Gastrointestinal Agents, Others


  • Do not take simethicone if you are hypersensitive to simethicone or any of the components in the formulation.
  • Can cause false-negative gastric guaiac test, a test done to detect invisible (occult) blood in stool.

What is simethicone, and what is it used for?

Simethicone is an antiflatulent medication used to relieve gas retention in the gastrointestinal (GI) tract. Simethicone is available over the counter (OTC) in various oral formulations and may be used in both adults and children. Simethicone relieves the feeling of fullness, bloating, pressure and discomfort from gas in the stomach.

Simethicone is a silicone compound that is not systemically absorbed from the gastrointestinal tract and is excreted in the stools. Simethicone is a surfactant that changes the surface tension of gas bubbles causing them to collapse, which enables easier passage of gas and prevents the formation of gas pockets in the GI tract. Simethicone, however, does not prevent the formation of gas in the GI tract or treat conditions that increase gas production.

What are the side effects of simethicone?

Common side effects of simethicone include:

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

  • Serious heart symptoms include fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness;
  • Severe headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
  • Severe nervous system reaction with very stiff muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, and feeling like you might pass out; or
  • Serious eye symptoms include blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.


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What are the dosages of simethicone?


  • 80 mg
  • 125 mg


  • 125 mg
  • 180 mg

Tablet, Chewable

  • 80 mg
  • 125 mg

Liquid, Oral

  • 20 mg/0.3mL

Oral Suspension

  • 20 mg/0.3mL
  • 40 mg/0.6mL

Strip, Orally Disintegrating

  • 40 mg
  • 62.5 mg

Gas Retention in Gastrointestinal Tract


  • 40-360 mg orally every 6 hours after meals and at bedtime as needed; not to exceed 500 mg/day


  • Children younger than 2 years: 20 mg (0.3 mL) orally every 6 hours after meals and at bedtime; not to exceed 240 mg/day
  • Children 2-12 years: 40 mg (0.6 mL) orally every 6 hours after meals and at bedtime; not to exceed 480 mg/day
  • Children older than 12 years: 40-360 mg orally every 6 hours after meals and at bedtime; not to exceed 500 mg/day

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  • Orally administered simethicone is not absorbed systemically and there are no known reports of overdose.
  • In case of overdose, discontinue simethicone and report to Poison Control if you experience any symptoms.

What drugs interact with simethicone?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Simethicone has no known severe, serious, moderate or mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • Oral simethicone is not absorbed systemically and is acceptable for use in pregnancy and breastfeeding.
  • Check with your healthcare provider before taking any OTC drug, including simethicone if you are pregnant or breastfeeding.

What else should I know about simethicone?

  • Take simethicone exactly as per label instructions.
  • Chewable tablets should be chewed thoroughly before swallowing. Liquid-filled capsules should not be chewed.
  • Store safely out of reach of children.


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Medically Reviewed on 7/13/2022