Dosing and uses of Imodium, K-Pek II (loperamide)
Adult dosage forms and strengths
liquid
- 1mg/5mL
- 1mg/7.5mL
suspension
- 1mg/7.5mL
tablet
- 2mg
capsule
- 2mg
tablet chewable
- 2mg
Acute Diarrhea
4 mg initially, then 2 mg after each loose stool; not to exceed 16 mg/day (8 mg/day for self-medication); discontinue if no improvement seen within 48 hours
Chronic Diarrhea
4 mg initially, then 2 mg after each loose stool until controlled, and then 4-8 mg/day in divided doses
Traveler's Diarrhea
4 mg after first loose stool, then 2 mg after each subsequent stool; not to exceed 8 mg/day
Pediatric dosage forms and strengths
liquid
- 1mg/5mL
- 1mg/7.5mL
suspension
- 1mg7.5mL
tablet
- 2mg
capsule
- 2mg
tablet chewable
- 2mg
Acute Diarrhea
First Day of Treatment
- 2-6 years (13-20 kg): 1 mg q8hr PO
- 6-8 years: (20-30 kg): 2 mg q12hr PO
- 8-12 years (>30 kg): 2 mg q8hr PO
Second & Subsequent Doses
- 0.1 mg/kg PO after each loose stool; not to exceed dose recommended for first 24 hours
Chronic Diarrhea
0.08-0.24 mg/kg/day PO divided q12hr
Traveler's Diarrhea
<6 years: Safety and efficacy not established
6-8 years: 2 mg after first loose stool, then 1 mg after each subsequent stool; not to exceed 4 mg/day
8-12 years: 2 mg after first loose stool, then 1 mg after each subsequent stool; not to exceed 6 mg/day
>12 years: 4 mg after first loose stool, then 2 mg after each subsequent stool; not to exceed 8 mg/day
Imodium, K-Pek II (loperamide) adverse (side) effects
Frequency not defined
Dizziness
Fatigue
Abdominal pain
Constipation
Nausea
Dry mouth
Angioedema
Bullous eruptions
Flatulence
Rash
Postmarketing Reports
Pancreatitis
Warnings
Contraindications
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 <2 years
Cautions
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 seen within 48 hours 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 (ie, 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
Use with caution in patients with hepatic impairment due to reduced 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
Potential toxic dose in patients <6 years: 0.4 mg/kg
Pregnancy and lactation
Pregnancy category: B
Lactation: Not known if distributed in breast milk; use caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Imodium, K-Pek II (loperamide)
Mechanism of action
Slows intestinal motility through opioid receptor; has direct effects on circular and longitudinal muscle; reduces fecal volume; increases viscosity
Absorption
Bioavailability: 0.3%
Onset: 1-3 hr
Duration: 41 hr
Peak plasma time: 5 hr (capsule); 2.5 hr (liquid)
Distribution
Poor penetration through blood-brain barrier
Metabolism
Significant first-pass metabolism, resulting in very low plasma level of drug
Metabolites: Glucuronide (inactive)
Elimination
Elimination half-life: 7-14 hr
Excretion: Feces (30-40%), urine (1%)