Clinical Trial Data
The adverse effects reported during clinical investigations of IMODIUM® (loperamide hydrochloride) are difficult to distinguish from symptoms associated with the diarrheal syndrome. Adverse experiences recorded during clinical studies with IMODIUM® (loperamide hcl) were generally of a minor and self-limiting nature. They were more commonly observed during the treatment of chronic diarrhea.
The adverse events reported are summarized irrespective of the causality assessment of the investigators.
1) Adverse events from 4 placebo-controlled studies in patients with acute diarrhea The adverse events with an incidence of 1.0% or greater, which were reported at least as often in patients on loperamide hydrochloride as on placebo, are presented in the table below.
|No. of treated patients||231||236|
| Gastrointestinal AE%
The adverse events with an incidence of 1.0% or greater, which were more frequently reported in patients on placebo than on loperamide hydrochloride, were: dry mouth, flatulence, abdominal cramp and colic.
2) Adverse events from 20 placebo-controlled studies in patients with chronic diarrhea
The adverse events with an incidence of 1.0% or greater, which were reported at least as often in patients on loperamide hydrochloride as on placebo, are presented below in the table below.
|No. of treated patients||285||277|
| Gastrointestinal AE%
| Central and peripheral
nervous system AE%
The adverse events with an incidence of 1.0% or greater, which were more frequently reported in patients on placebo than on loperamide hydrochloride were: nausea, vomiting, headache, meteorism, abdominal pain, abdominal cramp and colic.
3) Adverse events from seventy-six controlled and uncontrolled studies in patients with acute or chronic diarrhea
The adverse events with an incidence of 1.0% or greater in patients from all studies are given in the table below.
|Acute Diarrhea||Chronic Diarrhea||All Studiesa|
|No. of treated patients||1913||1371||3740|
|a. All patients in all studies, including those in which it was not specified if the adverse events occurred in patients with acute or chronic diarrhea.|
Post -marketing experience
The following adverse events have been reported:
Skin and subcutaneous tissue disorders
Rash, pruritus, urticaria, angioedema, and extremely rare cases of bullous eruption including erythema multiforme, Stevens-Johnson syndrome and Toxic Epidermal Necrolysis have been reported with use of IMODIUM (loperamide hcl) .
Immune system disorders
Isolated occurrences of allergic reactions and in some cases severe hypersensitivity reactions including anaphylactic shock and anaphylactoid reactions have been reported with the use of IMODIUM (loperamide hcl) .
Renal and urinary disorders
Nervous system disorders
General disorders and administrative site conditions
A number of the adverse events reported during the clinical investigations and post- marketing experience with loperamide are frequent symptoms of the underlying diarrheal syndrome (abdominal pain/discomfort, nausea, vomiting, dry mouth, tiredness, drowsiness, dizziness, constipation, and flatulence). These symptoms are often difficult to distinguish from undesirable drug effects.
Drug Abuse And Dependence
A specific clinical study designed to assess the abuse potential of loperamide at high doses resulted in a finding of extremely low abuse potential.
Studies in morphine-dependent monkeys demonstrated that loperamide hydrochloride at doses above those recommended for humans prevented signs of morphine withdrawal. However, in humans, the naloxone challenge pupil test, which when positive indicates opiate-like effects, performed after a single high dose, or after more than two years of therapeutic use of IMODIUM® (loperamide hydrochloride), was negative. Orally administered IMODIUM® (loperamide hcl) (loperamide formulated with magnesium stearate) is both highly insoluble and penetrates the CNS poorly.
Read the Imodium (loperamide hcl) Side Effects Center for a complete guide to possible side effects »
Nonclinical data have shown that loperamide is a P-glycoprotein substrate. Concomitant administration of loperamide (16 mg single dose) with a 600 mg single dose of either quinidine, or ritonavir, both of which are P-glycoprotein inhibitors, resulted in a 2- to 3- fold increase in loperamide plasma levels. Due to the potential for enhanced central effects when loperamide is coadministered with quinidine and with ritonavir, caution should be exercised when loperamide is administered at the recommended dosages (2 mg, up to 16 mg maximum daily dose) with P-glycoprotein inhibitors.
When a single 16-mg dose of loperamide is coadministered with a 600 mg single dose of saquinavir, loperamide decreased saquinavir exposure by 54%, which may be of clinical relevance due to reduction of therapeutic efficacy of saquinavir. The effect of saquinavir on loperamide is of less clinical significance. Therefore, when loperamide is given with saquinavir, the therapeutic efficacy of saquinavir should be closely monitored.
Last reviewed on RxList: 3/18/2008
This monograph has been modified to include the generic and brand name in many instances.
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