Drug Guide
Loperamide Hydrochloride and Simethicone
Classification
Therapeutic: Antidiarrheal
Pharmacological: Peripherally acting opioid receptor agonist (Loperamide) and Antigas (Simethicone)
FDA Approved Indications
- Short-term management of diarrhea, including traveler's diarrhea, in adults and children 6 years and older.
- Relief of bloating, pressure, and discomfort caused by excess gas in the digestive tract (Simethicone).
Mechanism of Action
Loperamide acts on opioid receptors in the gut wall to decrease motility and prolong transit time, enhancing absorption of fluids and electrolytes. Simethicone decreases surface tension of gas bubbles, facilitating their coalescence and easier passage through the gastrointestinal tract.
Dosage and Administration
Adult: Loperamide: 4 mg initially, then 2 mg after each loose stool. Do not exceed 16 mg/day.
Pediatric: Children 6-12 years: 2 mg after each loose stool, not to exceed 8 mg/day. Use with caution and consult pediatric guidelines.
Geriatric: Adjust doses carefully due to potential increased sensitivity and risk of side effects.
Renal Impairment: No specific adjustment recommended; use with caution.
Hepatic Impairment: Use caution; no specific dosage adjustment established.
Pharmacokinetics
Absorption: Well absorbed from the gastrointestinal tract.
Distribution: Wide distribution, crosses the blood-brain barrier minimally.
Metabolism: Primarily hepatic via CYP3A4 and CYP2C8 enzymes.
Excretion: Fecal excretion of unchanged drug and metabolites; minimal urinary excretion.
Half Life: Approximately 10.4 hours.
Contraindications
- Acute dysentery,5 bloody or mucus-containing stool, bacterial enterocolitis caused by pathogens sensitive to opioids, pseudomembranous colitis associated with broad-spectrum antibiotics.
- Known hypersensitivity to components.
Precautions
- Use caution in patients with hepatic impairment, as drug metabolism may be affected.
- Monitor for signs of ileus or toxic megacolon, especially with excessive or prolonged use.
- Pregnancy and Lactation: Limited data; use only if clearly needed and benefits outweigh risks.
Adverse Reactions - Common
- Constipation (Common)
- Nausea (Common)
- Abdominal pain (Less common)
Adverse Reactions - Serious
- Toxic megacolon (Rare)
- Cardiac arrhythmias (especially with overdose) (Rare)
Drug-Drug Interactions
- CNS depressants may enhance sedative effects.
- Pimozide and quinidine: risk of cardiac arrhythmias due to QT prolongation.
Drug-Food Interactions
- None specifically noted.
Drug-Herb Interactions
- Caution with herbal products that may cause GI motility changes.
Nursing Implications
Assessment: Monitor stool frequency and consistency, dehydration signs, and bowel sounds.
Diagnoses:
- Risk for dehydration related to diarrhea.
- Impaired comfort related to gastrointestinal symptoms.
Implementation: Administer as per dosing guidelines. Educate patient on signs of constipation or toxicity.
Evaluation: Efficacy assessed by reduction in diarrhea frequency and relief of gas symptoms.
Patient/Family Teaching
- Instruct patients to follow dosing instructions carefully.
- Advise against exceeding the recommended dose.
- Warn about potential constipation and when to seek medical attention.
- Advise to seek medical attention for persistent diarrhea exceeding 48 hours or bloody stools.
Special Considerations
Black Box Warnings:
- Serious adverse cardiovascular events, including QT prolongation and Torsades de Pointes, especially in overdose or with concomitant use of other QT-prolonging drugs.
Genetic Factors: Limited data.
Lab Test Interference: None noted.
Overdose Management
Signs/Symptoms: Drowsiness, ileus, urinary retention, acute cardiac events including arrhythmias.
Treatment: Supportive care; activated charcoal if ingestion was recent; ECG monitoring; specific antidote unavailable.
Storage and Handling
Storage: Store at room temperature, 20-25°C (68-77°F).
Stability: Stable under recommended storage conditions.