Loperamide / simethicone Side Effects
For the Consumer
Applies to loperamide / simethicone: oral tablet, oral tablet chewable
What are some side effects that I need to call my doctor about right away?
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Very bad dizziness or passing out.
- Chest pain or pressure or a fast heartbeat.
- A heartbeat that does not feel normal.
- Very upset stomach or throwing up.
- Belly pain.
- Hard stools (constipation).
- Swelling of belly.
- Black, tarry, or bloody stools.
- Not able to pass urine or change in how much urine is passed.
What are some other side effects of this drug?
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Feeling sleepy.
- Feeling tired or weak.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.
For Healthcare Professionals
Necrotizing enterocolitis with perforation was reported in two women following short courses (24 hours and 3 days) of loperamide for the treatment of acute diarrhea with fever. Resected bowel in both cases revealed extensive mucosal hemorrhage and necrosis.
Toxic megacolon has been reported in association with the use of loperamide to treat symptoms of ulcerative colitis and pseudomembranous colitis due to antibiotic therapy. In one patient treated for ulcerative colitis, abdominal symptoms seemed to improve in the days before requiring emergency laparotomy.
Loperamide has also been implicated in a case of appendicitis. A 35-year-old male self-treated travelers' diarrhea with loperamide at greater than recommended daily dose for seven days. Three days later, an appendolith was noted during an emergency appendectomy. The authors speculated that fecal stasis induced by loperamide increases the risk of fecalith and appendolith formation, the latter being associated with the pathogenesis of appendicitis.
Cases of paralytic ileus associated with abdominal distention have been reported rarely with use of loperamide. Many of these reports had occurred in a setting with acute dysentery, overdose, and children less than 2 years old.[Ref]
Gastrointestinal side effects of loperamide have included nausea, vomiting, dyspepsia, abdominal cramps, anorexia, abdominal pain, abdominal distention, dry mouth, abdominal discomfort, and constipation. Gastrointestinal side effects have rarely included ileus, toxic megacolon, and necrotizing enterocolitis with or without perforation.[Ref]
Severe central nervous system depression may occur with overdose of loperamide.[Ref]
Other side effects of loperamide have rarely included physical dependence.[Ref]
While structurally related to meperidine and diphenoxylate, abuse potential is very low with loperamide. At therapeutic doses, it does not produce euphoria.
In opioid addicted monkeys, loperamide in high doses did prevent withdrawal symptoms.
A 26-year-old male with a history of opioid and alcohol abuse, began taking loperamide for the treatment of acute diarrhea. Despite denying euphoric effects from the drug, he gradually increased his intake to 320 mg per day. Attempts to stop the drug resulted in acute withdrawal (chest pain, shortness of breath, chills, diaphoresis, abdominal discomfort, nausea. and vomiting). Methadone relieved the symptoms. A slow methadone taper in an inpatient setting was successful in treating the physical dependence.[Ref]
Dermatologic side effects have associated with loperamide therapy included rash, pruritus, urticaria, and angioedema. Bullous eruptions including erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis (TEN) have been reported rarely.[Ref]
Simethicone has no known side effects.[Ref]
1. Olm M, Gonzalez FJ, Garcia-Valdecasas JC, Fuster J, Bertran A, Milla J "Necrotising colitis with perforation in diarrhoic patients treated with loperamide." Eur J Clin Pharmacol 40 (1991): 415-6
2. Ericsson CD, Johnson PC "Safety and efficacy of loperamide." Am J Med 88 (1990): s10-4
3. Brown JW "Toxic megacolon associated with loperamide therapy." JAMA 241 (1979): 501-2
4. Walley T, Milson D "Loperamide related toxic megacolon in Clostridium difficile colitis." Postgrad Med J 66 (1990): 582
5. Forgue ST, Shyu WC, Gleason CR, et al "Pharmacokinetics of the novel cephalosporin cefepime (BMY-28142) in rats and monkeys." Antimicrob Agents Chemother 31 (1987): 799-804
6. Katz JP, Sturmann KM "Appendicitis associated with loperamide hydrochloride abuse." Ann Pharmacother 27 (1993): 369-70
7. Hill MA, Greason FC "Loperamide dependence." J Clin Psychiatry 53 (1992): 450
8. "Multum Information Services, Inc. Expert Review Panel"
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.