Imodium Side Effects

Generic name: loperamide

Note: This document contains side effect information about loperamide. Some of the dosage forms listed on this page may not apply to the brand name Imodium.

Some side effects of Imodium may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to loperamide: oral capsule, oral liquid, oral suspension, oral tablet, oral tablet chewable

Get emergency medical help if you have any of these signs of an allergic reaction while taking loperamide (the active ingredient contained in Imodium) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop taking loperamide and call your doctor at once if you have a serious side effect such as:

• stomach pain or bloating;

• ongoing or worsening diarrhea;

• diarrhea that is watery or bloody; or

• severe skin reaction -- fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Less serious side effects of loperamide may include:

• dizziness;

• drowsiness, tired feeling;

• constipation;

• mild stomach pain; or

• mild skin rash or itching.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to loperamide: compounding powder, oral capsule, oral liquid, oral suspension, oral tablet, oral tablet chewable

Gastrointestinal

Necrotizing enterocolitis with perforation was reported in two women following short courses (24 hours and 3 days) of loperamide (the active ingredient contained in Imodium) 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 traveler's diarrhea with loperamide at greater than the recommended daily dose for seven days. Three days later, an appendalith was noted during an emergency appendectomy. The authors speculated that fecal stasis induced by loperamide increases the risk of fecalith and appendalith formation, the latter being associated with the pathogenesis of appendicitis.

Gastrointestinal side effects reported during loperamide therapy are often likely due to the underlying illness and include nausea, vomiting, dyspepsia, abdominal cramps, and anorexia.

Cases of paralytic ileus associated with abdominal distention have been reported rarely. Many of these reports had occurred in a setting with acute dysentery, overdose, and children less than 2-years-old.

Gastrointestinal side effects 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.

Nervous system

Severe central nervous system depression may occur with overdose.

Nervous system side effects have rarely included drowsiness, tiredness, dizziness and severe central nervous system depression.

Other

While structurally related to meperidine and diphenoxylate, abuse potential is very low with loperamide (the active ingredient contained in Imodium) 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.

Other side effects have rarely included physical dependence.

Hypersensitivity

Hypersensitivity side effects have included skin rash. Anaphylactic shock and anaphylactoid reactions have been reported rarely.

Dermatologic

Dermatologic side effects have included rash, pruritus, urticaria, and angioedema. Bullous eruptions including erythema multiforme, Stevens-Johnson syndrome, and Toxic Epidermal Necrolysis (TEN) have been reported rarely.

Genitourinary

Genitourinary side effects have included urinary retention.

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