Drug Guide
Amoxicillin, Clarithromycin, Lansoprazole
Classification
Therapeutic: Helicobacter pylori eradication therapy, Infectious disease treatment, Gastric acid suppression
Pharmacological: Amoxicillin: Penicillin antibiotic; Clarithromycin: Macrolide antibiotic; Lansoprazole: Proton pump inhibitor
FDA Approved Indications
- Treatment of Helicobacter pylori infection in combination with other agents; gastric ulcers; GERD
Mechanism of Action
Amoxicillin inhibits bacterial cell wall synthesis; Clarithromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit; Lansoprazole irreversibly inhibits the H+/K+ ATPase enzyme system of gastric parietal cells, reducing stomach acid production.
Dosage and Administration
Adult: As per specific regimen, typically once or twice daily, with food or as directed by a physician.
Pediatric: Dosage based on weight and age; consult specific regimen.
Geriatric: Adjust based on renal and hepatic function; monitor for side effects.
Renal Impairment: Use with caution; dosage adjustment may be necessary.
Hepatic Impairment: Monitor; adjust if necessary due to decreased drug metabolism.
Pharmacokinetics
Absorption: Amoxicillin: Well absorbed; Clarithromycin: Well absorbed; Lansoprazole: Well absorbed with food enhancing absorption.
Distribution: Widely distributed; Clarithromycin penetrates tissues well.
Metabolism: Clarithromycin and Lansoprazole are extensively metabolized hepatically; Amoxicillin is excreted mostly unchanged.
Excretion: Amoxicillin: Renal; Clarithromycin: Hepatic and renal; Lansoprazole: Hepatic.
Half Life: Amoxicillin: ~1 hour; Clarithromycin: ~5-7 hours; Lansoprazole: ~1-2 hours.
Contraindications
- Allergy to penicillins, macrolides, or proton pump inhibitors.
- History of cholestatic jaundice or hepatic impairment related to lansoprazole.
Precautions
- Monitor liver function during therapy; use cautiously in patients with cardiac arrhythmias due to clarithromycin.
Adverse Reactions - Common
- Diarrhea (Common)
- Nausea (Common)
- Headache (Common)
Adverse Reactions - Serious
- Clostridioides difficile-associated diarrhea (Serious)
- Anaphylaxis (Rare)
- Hepatotoxicity (Rare)
Drug-Drug Interactions
- Warfarin, affecting bleeding risk; Other CYP3A4 substrates affected by clarithromycin; Increased serum concentrations of methotrexate
Drug-Food Interactions
- Alcohol may increase gastric irritation.
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor for allergic reactions, gastrointestinal symptoms, hepatic function, and response to therapy.
Diagnoses:
- Risk for infection, secondary to antimicrobial therapy; Risk for impaired skin integrity, related to diarrhea.
Implementation: Administer as prescribed; monitor for adverse effects and effectiveness; educate patient on completing therapy.
Evaluation: Assess symptom resolution, adherence, and any adverse reactions.
Patient/Family Teaching
- Take medications exactly as prescribed, preferably with food to reduce gastric irritation.
- Report any signs of allergic reactions, severe diarrhea, or jaundice.
- Do not stop therapy early.
- Avoid alcohol and avoid taking other medications without consulting healthcare provider.
Special Considerations
Black Box Warnings:
- Potential for QT prolongation with clarithromycin, especially in patients with risk factors.
Genetic Factors: Consider CYP3A4 polymorphisms affecting clarithromycin metabolism.
Lab Test Interference: May affect liver function tests; intermittently cause false positives in some drug screenings.
Overdose Management
Signs/Symptoms: Gastrointestinal disturbances, such as nausea, vomiting, and diarrhea; possible allergic reactions.
Treatment: Supportive care; activated charcoal if ingestion is recent; symptomatic treatment as needed.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable under recommended conditions; check expiration date before use.