Reviewed on 12/15/2022

What Is Loperamide-Simethicone and How Does It Work?

Loperamide-Simethicone is a combination over-the-counter medications used to treat diarrhea and flatulence.

  • Loperamide-Simethicone is available under the following different brand names: Imodium Multi-Symptom Relief

What Are Side Effects Associated with Using Loperamide-Simethicone?

Common side effects of Loperamide-Simethicone include:

  • Dizziness,
  • Drowsiness,
  • Tiredness,
  • Constipation,
  • Stomach pain,
  • Skin rash, or
  • Itching.

Serious side effects of Loperamide-Simethicone include:

  • Severe constipation/nausea/vomiting,
  • Stomach or abdominal pain, or
  • Uncomfortable fullness of the stomach or abdomen.

Rare side effects of Loperamide-Simethicone include:

  • none 

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

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

What Are the Dosages of Loperamide-Simethicone?


Adult and geriatric dosage

  • After each loose bowel movement: 2 tablets once initially, then 1 tablet/dose with each subsequent loose stool up to tablet/day

Pediatric dosage

  • Children below 6 years: Safety and efficacy not established
  • 6-8 years: 1 tablet once initially, then one-half tablet/dose, up to 2 tablets/day
  • 9-12 years: 1 tablet once initially, then one-half tablet/dose, up to 3 tablets/day
  • Children above 12 years: After each loose bowel movement: 2 tablets once initially, then 1 tab/dose with each subsequent loose stool up to 4 tabs/day

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”


Super Tips to Boost Digestive Health: Bloating, Constipation, and More See Slideshow

What Other Drugs Interact with Loperamide-Simethicone?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Loperamide-Simethicone has minor interactions with no other drugs.
  • Loperamide-Simethicone has serious interactions with at least 33 other drugs.
  • Loperamide-Simethicone has moderate interactions with at least 59 other drugs.
  • Loperamide-Simethicone has minor interactions with the following drugs:

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Loperamide-Simethicone?


  • Hypersensitivity, bloody diarrhea, high fever, infectious diarrhea, pseudomembranous colitis
  • Patients in whom constipation must be avoided
  • Abdominal pain without diarrhea
  • Avoid use as primary therapy with acute dysentery (bloody stools and high fever, acute ulcerative colitis, bacterial enterocolitis [caused by Salmonella, Shigella, and Campylobacter), pseudomembranous colitis associated with antibiotic use)
  • Age below 2 years

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Loperamide-Simethicone?”
  • Long-Term Effects
  • See “What Are Side Effects Associated with Using Loperamide-Simethicone?”


  • Chewable tab should be chewed thoroughly before swallowing
  • Loperamide
    • May cause drowsiness or dizziness, which may impair physical abilities to operate heavy machinery or tasks requiring mental alertness
    • Hypersensitivity reactions reported, including anaphylaxis, rash, urticaria, and rare cases of Steven’s Johnson syndrome or toxic epidermal necrolysis
    • Discontinue if no improvement is seen within 48 hr in patients with acute diarrhea, symptoms worsen, or abdominal swelling or bulging develops
    • Discontinue promptly if constipation, abdominal pain or distention, blood in stool, or ileus develops; do not use when peristalsis inhibition should be avoided (.e, due to potential for ileus, megacolon, or toxic megacolon)
    • Discontinue therapy if symptoms of abdominal distention occur in patients with AIDS; cases of toxic megacolon reported with infectious colitis, resulting from viral or bacterial pathogens
    • Taking more than directed can cause serious heart problems or death
    • Use with caution in patients with hepatic impairment first-passed first-pass metabolism; monitor for signs of CNS toxicity
    • Use of higher than recommended doses or abuse of loperamide can result in serious cardiac adverse events, including QT interval prolongation, Torsades de Pointes, or other ventricular arrhythmias, syncope, and cardiac arrest; in cases of abuse, individuals often use other drugs together with loperamide in attempts to increase its absorption and penetration across the blood-brain barrier, inhibit loperamide metabolism, and enhance its euphoric effects
  • Simethicone
    • Can cause false-negative gastric guaiac test

Pregnancy and Lactation

  • May be acceptable (loperamide).
  • Use with caution if the benefits outweigh the risks during pregnancy. (simethicone)
  • Lactation
    • Unknown if distributed into breast milk, use caution
    • Pregnant or breastfeeding patients should seek advice from health professionals before using OTC drugs.

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