General

Allergic Reactions

Extremely rare allergic reactions including anaphylaxis and anaphylactic shock have been reported.

Hepatic Impairment

The effects of hepatic impairment on the pharmacokinetics of loperamide have not been studied. Use loperamide hydrochloride with caution in such patients because the systemic exposure to loperamide may be increased due to reduced metabolism. Monitor patients with hepatic impairment closely for signs of central nervous system (CNS) toxicity.

Renal Impairment

No pharmacokinetic data are available in patients with renal impairment. Since it has been reported that the majority of the drug is metabolized and metabolites or the unchanged drug are excreted mainly in the feces, dosage adjustments in patients with renal impairment are not required.

Geriatric Use

No formal studies have been conducted to evaluate the pharmacokinetics of loperamide in elderly subjects. However, in two studies that enrolled elderly patients, there were no major differences in the drug disposition in elderly patients with diarrhea relative to young patients.

In general, elderly patients may be more susceptible to drug-associated effects on the QT interval. Avoid loperamide hydrochloride in elderly patients taking drugs that can result in prolongation of the QT interval (for example, Class IA or III antiarrhythmics) or in patients with risk factors for Torsades de Pointes (see WARNINGS).

Information for Patients

Advise patients:

• to take loperamide hydrochloride at the prescribed dosage. Use of a higher than prescribed dosage is not recommended (see WARNINGS). Report to a healthcare facility if you or someone you are caring for taking loperamide hydrochloride experiences fainting episode, a rapid or irregular heartbeat or become unresponsive.
• with acute diarrhea, that if clinical improvement is not observed in 48 hours, discontinue loperamide hydrochloride and contact their healthcare provider.
• to contact their healthcare provider if they see blood in their stools, or if they develop a fever or abdominal distention.
• to use caution when driving a car or operating machinery, as tiredness, dizziness, or drowsiness may occur in the setting of diarrheal syndromes treated with loperamide hydrochloride (see ADVERSE REACTIONS).
• to tell their healthcare provider about all the medications they are taking, including prescription and over-the-counter medications, vitamins and herbal supplements, especially if they take Class 1A (e.g., quinidine, procainamide) or Class III (e.g., amiodarone, sotalol) antiarrhythmics, antipsychotics (e.g., chlorpromazine, haloperidol, thioridazine, ziprasidone), antibiotics (e.g., moxifloxacin), or any other drug known to prolong the QT interval (e.g., pentamidine, levomethadyl acetate, methadone).

Drug Interactions

Effects of Other Drugs on Loperamide

Concomitant use of loperamide hydrochloride with inhibitors of CYP3A4 (e.g., itraconazole) or CYP2C8 (e.g., gemfibrozil) or inhibitors of P-glycoprotein (e.g., quinidine, ritonavir) can increase exposure to loperamide. The increased systemic exposure to loperamide may increase a risk for cardiac adverse reactions especially in patients who are taking multiple CYP enzyme inhibitors, or in patients with underlying cardiac conditions (see WARNINGS). Monitor patients for cardiac adverse reactions.

CYP3A4 Inhibitors

Itraconazole

Concomitant administration of multiple doses of 100 mg itraconazole twice daily, an inhibitor of both CYP3A4 and P-glycoprotein, with a single 4 mg dose of loperamide hydrochloride increased the peak plasma concentration and the systemic exposure to loperamide by 2.9-fold and 3.8-fold, respectively.

CYP2C8 Inhibitors

Gemfibrozil

When a single 4 mg dose of loperamide hydrochloride was coadministered with 600 mg gemfibrozil, a strong inhibitor of CYP2C8, on day 3 of a 5-day treatment with gemfibrozil twice daily, the mean peak plasma concentration and the systemic exposure to loperamide was increased by 1.6-fold and 2.2-fold, respectively.

CYP3A4 and CYP2C8 Inhibitors

When multiple doses of both 100 mg itraconazole and 600 mg gemfibrozil twice daily were administered with a single 4 mg dose of loperamide hydrochloride, the mean peak plasma concentration and the systemic exposure to loperamide was increased by 4.2-fold and 12.6-fold, respectively.

P-glycoprotein Inhibitors

Concomitant administration of a 16 mg single dose of loperamide hydrochloride with a 600 mg single dose of quinidine or ritonavir, both of which are P-glycoprotein inhibitors, resulted in a 2- to 3-fold increase in loperamide plasma concentrations. Due to the potential for enhanced CNS adverse reactions when loperamide is coadministered with quinidine and with ritonavir, caution should be exercised when loperamide hydrochloride capsules are administered at the recommended dosages (2 mg, up to 16 mg maximum daily dose) with P-glycoprotein inhibitors.

Effects of Loperamide on Other Drugs

Saquinavir

When a single 16 mg dose of loperamide hydrochloride 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.

Carcinogenesis, mutagenesis, impairment of fertility

In an 18 month rat study with oral loperamide hydrochloride doses up to 40 mg/kg/day (21 times the maximum human dose of 16 mg/day, based on a body surface area comparison), there was no evidence of carcinogenesis.

Loperamide was not genotoxic in the Ames test, the SOS chromotest in E. coli, the dominant lethal test in female mice, or the mouse embryo cell transformation assay.

Fertility and reproductive performance was evaluated in rats using oral doses of 2.5, 10, and 40 mg/kg/day (females only) in a second study. Oral administration of 20 mg/kg/day (approximately 11 times the human dose based on a body surface area comparison) and higher, produced a strong impairment of female fertility. Treatment of female rats with up to 10 mg/kg/day (approximately 5 times the human dose based on a body surface area comparison) had no effect on fertility. Treatment of male rats with oral doses of 40 mg/kg/day (approximately 21 times the human dose based on a body surface area comparison) produced impairment of male fertility, whereas administration of up to 10 mg/kg/day (approximately 5 times the human dose based on a body surface area comparison) had no effect.

Pregnancy

Nursing Mothers

Small amounts of loperamide may appear in human breast milk. Therefore, loperamide hydrochloride is not recommended during breast-feeding.

Pediatric Use

Loperamide hydrochloride is contraindicated in pediatric patients less than 2 years of age due to the risks of respiratory depression and serious cardiac adverse reactions (see CONTRAINDICATIONS). Postmarketing cases of cardiac arrest, syncope, and respiratory depression have been reported in pediatric patients less than 2 years of age (see WARNINGS). Pediatric patients may be more sensitive to CNS effects, such as altered mental status, somnolence, and respiratory depression, than adults. There have been rare reports of paralytic ileus associated with abdominal distention. Most of these reports occurred in the setting of acute dysentery, overdose, and with pediatric patients less than two years of age.

Loperamide hydrochloride should be used with special caution in pediatric patients because of their greater variability of response (see WARNINGS). Dehydration, particularly in pediatric patients less than 6 years of age, may further influence the variability of response to loperamide hydrochloride.

The safety and effectiveness of loperamide hydrochloride in pediatric patients with chronic diarrhea have not been established. Although loperamide hydrochloride has been studied in a limited number of pediatric patients with chronic diarrhea; the therapeutic dose for the treatment of chronic diarrhea in a pediatric population has not been established.

In case of accidental overdosage of loperamide hydrochloride by pediatric patients, see OVERDOSAGE for suggested treatment.

Clinical Trial Experience

The adverse effects reported during clinical investigations of loperamide hydrochloride are difficult to distinguish from symptoms associated with the diarrheal syndrome. Adverse experiences recorded during clinical studies with loperamide hydrochloride 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.

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.

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.

Postmarketing Experience

The following adverse events have been reported:

Cardiac disorders

QT/QTc interval prolongation, Torsades de Pointes, other ventricular arrhythmias, cardiac arrest, syncope, and death (see WARNINGS, OVERDOSAGE).

Skin and subcutaneous tissue disorders

Rash, pruritus, urticaria, and angioedema and extremely rare cases bullous eruption including erythema multiforme, Stevens-Johnson syndrome and Toxic Epidermal Necrolysis have been reported with use of loperamide hydrochloride.

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 loperamide hydrochloride.

Gastrointestinal disorders

Dry mouth, abdominal pain, distention or discomfort, nausea, vomiting, flatulence, dyspepsia, constipation, paralytic ileus, megacolon; including toxic megacolon (see CONTRAINDICATIONS, WARNINGS).

Renal and urinary disorders

Urinary retention

Nervous system disorders

Drowsiness, dizziness

General disorders and administrative site conditions

Tiredness

A number of the adverse events reported during the clinical investigations and postmarketing 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.

Controlled Substance

Loperamide is not a controlled substance.

Abuse

Loperamide is a mu-opioid agonist. A human abuse potential study of loperamide hydrochloride at single doses up to 60 mg (3.75 times the recommended maximum adult dosage of 16 mg per day) was compared, in a double-blind cross-over design using nine subjects who had been active opiate users, to a threshold dose of codeine sulfate at 120 mg (96 mg base) or placebo. This resulted in one subject (11%) feeling a drug on placebo and identifying it as "dope" (heroin) and liking it slightly. Codeine was felt by 56% of subjects and identified as "dope" by 44%. Loperamide was felt by 44% of subjects and identified as "dope" by 11% and possibly dope mixed with some other kind of drug by another 22%. Loperamide abuse and misuse have been reported, especially at doses of 60 mg or greater. Loperamide can have greater CNS opioid effects at higher doses or with coadministration of drugs that increase systemic exposure and/or increase CNS penetration of loperamide (through inhibition of the CYP450 enzyme system or inhibition of P-glycoprotein). Loperamide is primarily being misused for relief from opioid withdrawal, and abused by a few users who obtain some (reportedly mild-moderate) level of euphoria.

Dependence

In animals, parenteral administration of loperamide hydrochloride can cause physical dependence, cross-tolerance to opioids, and all the other pharmacologic effects typical of mu-opioid agonists. Studies in morphine-dependent monkeys demonstrated that loperamide hydrochloride at doses above those recommended for humans prevented signs of morphine withdrawal.

Acute Diarrhea

Adults and Pediatric Patients 13 Years and Older: The recommended initial dose is 4 mg (two capsules) followed by 2 mg (one capsule) after each unformed stool. The maximum daily dose is 16 mg (eight capsules). Clinical improvement is usually observed within 48 hours.

Pediatric Patients 2 to 12 Years of Age: In pediatric patients 2 to 5 years of age (20 kg or less), the non-prescription liquid formulation (loperamide hydrochloride oral solution 1 mg/5 mL) should be used; for ages 6 to 12, either loperamide hydrochloride capsules or loperamide hydrochloride oral solution may be used. For pediatric patients 2 to 12 years of age, the following schedule for capsules or liquid will usually fulfill initial dosage requirements:

Recommended First Day Dosage Schedule

Two to five years (13 to 20 kg): 1 mg three times daily (3 mg total daily dosage)

Six to eight years (20 to 30 kg): 2 mg twice daily (4 mg total daily dosage)

Eight to twelve years (greater than 30 kg): 2 mg three times daily (6 mg total daily dosage)

Recommended Subsequent Daily Dosage

Following the first treatment day, it is recommended that subsequent loperamide hydrochloride doses (1 mg/10 kg body weight) be administered only after a loose stool. The total daily dosage should not exceed recommended dosages for the first day.

Chronic Diarrhea

Adults

The recommended initial dose is 4 mg (two capsules) followed by 2 mg (one capsule) after each unformed stool until diarrhea is controlled, after which the dosage of loperamide hydrochloride capsules should be reduced to meet individual requirements. When the optimal daily dosage has been established, this amount may then be administered as a single dose or in divided doses. The average daily maintenance dosage in clinical trials was 4 to 8 mg (two to four capsules per day). The maximum daily dosage is 16 mg (eight capsules per day). If clinical improvement is not observed after treatment with 16 mg per day for at least 10 days, symptoms are unlikely to be controlled by further administration. Loperamide hydrochloride capsules administration may be continued if diarrhea cannot be adequately controlled with diet or specific treatment.

Elderly

No formal pharmacokinetic studies were conducted in elderly subjects. However, there were no major differences reported in the drug disposition in elderly patients with diarrhea relative to young patients. No dose adjustment is required for the elderly.

In general, elderly patients may be more susceptible to drug-associated effects of the QT interval. Avoid loperamide hydrochloride in elderly patients taking drugs that can result in prolongation of the QT interval (for example, Class IA or III antiarrhythmics) or in patients with risk factors for Torsades de Pointes (see WARNINGS).

Renal Impairment

No pharmacokinetic data are available in patients with renal impairment. Since the metabolites and the unchanged drug are mainly excreted in the feces, no dosage adjustment is required for patients with renal impairment (see PRECAUTIONS).

Hepatic Impairment

The pharmacokinetics of loperamide have not been studied in patients with hepatic impairment. Use loperamide hydrochloride with caution in such patients because the systemic exposure may be increased due to reduced metabolism (see PRECAUTIONS).