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loperamide (Imodium)

Tradename: Imodium. Indication: - adjunctive therapy for management of diarrhea - inflammatory bowel disease [4] Contraindications: 1) diarrhea secondary to infection 2) bloody diarrhea 3) temperature > 101 F Dosage: 1) 4 mg PO initially, then 2 mg PRN, max 16 mg/day 2) pediatrics: a) 1 mg TID if 13-20 kg b) 2 mg BID if 20-30 kg c) 2 mg TID if >30 kg 3) if clinical improvement is not noted in 48 hours, discontinue use Tabs: 2 mg. Elixir: 1 mg/5 mL. Pharmacokinetics: 1) 40% absorbed after oral administration 2) elimination 1/2life is approximately 11 hours 3) 25% of the drug is eliminated unchanged in the feces 4) does not cross blood brain barrier Adverse effects: - uncommon (< 1%) - sedation, fatigue, drowsiness, dizziness, rash, nausea/vomiting, constipation, abdominal cramping, dry mouth - 2 cases of fatal misuse of loperamide - both cases involved men with substance use disorder managed with buprenorphine who were using loperamide to self-treat opioid withdrawal [5] - cardiac arrhythmias with misuse & abuse [6,8] - QT interval prolongation, torsades de pointes or other ventricular arrhythmias, syncope, & cardiac arrest [8] - increasing reports of abuse [7] Laboratory: - not detected on urine opioid screens [7] Mechanism of action: 1) slows intestinal motility 2) affects water & electrolyte movement through the bowel 3) inhibits peristalsis by directly effecting circular & longitudinal muscles of the intestinal wall 4) acts on opioid receptors [5]

General

anti-motility agent; antiperistaltic agent

Properties

MISC-INFO: elimination route LIVER

Database Correlations

PUBCHEM correlations

References

  1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  2. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
  3. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  4. Deprecated Reference
  5. Orciari Herman A, Sadoughi S, Saitz R OTC Diarrhea Drug Increasingly Being Misused for Opioid Effects. Physician's First Watch, May 12, 2016 David G. Fairchild, MD, MPH, Editor-in-Chief Massachusetts Medical Society http://www.jwatch.org - Eggleston W et al Loperamide Abuse Associated With Cardiac Dysrhythmia and Death. Ann Emerg Med. 2016 Apr 26. PMID: 27140747 http://www.annemergmed.com/article/S0196-0644%2816%2930052-X/pdf
  6. FDA Saftey Communication. June 7, 2016 Loperamide (Imodium): Drug Safety Communication - Serious Heart Problems With High Doses From Abuse and Misuse. http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm505303.htm
  7. Pallin DJ Increasing Reports of Loperamide Abuse. NEJM Journal Watch. Nov 10, 2016 Massachusetts Medical Society (subscription needed) http://www.jwatch.org - Vakkalanka JP et al. Epidemiologic trends in loperamide abuse and misuse. Ann Emerg Med 2016 Nov 4 PMID: 27823872
  8. Brooks M. FDA Acts to Stem Misuse, Abuse of Antidiarrheal Loperamide. Medscape - Jan 30, 2018. https://www.medscape.com/viewarticle/891968 - FDA Safety Alert. Jan 30, 2018 Imodium (loperamide) for Over-the-Counter Use: Drug Safety Communication - FDA Limits Packaging To Encourage Safe Use. https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm594403.htm

Component-of

loperamide/simethicone