Home Drug Guide Erythromycin Stearate

Drug Guide

Generic Name

Erythromycin Stearate

Brand Names Erythrocin Stearate, Bristamycin, Ethril 250, Ethril 500, Wyamycin S, Pfizer-e, Erypar

Classification

Therapeutic: Antibiotic, Macrolide

Pharmacological: Protein synthesis inhibitor (macrolide)},

FDA Approved Indications

Bacterial infections caused by susceptible organisms, including respiratory tract infections, skin and soft tissue infections, and sexually transmitted diseases.

Mechanism of Action

Erythromycin inhibits bacterial protein synthesis by reversibly binding to the 50S ribosomal subunit, thereby inhibiting translocation of aminoacyl-tRNA.

Dosage and Administration

Adult: Typically 250-500 mg every 6 hours, depending on infection severity.

Pediatric: Dosing based on weight, usually 12.5-25 mg/kg/day divided into 4 doses.

Geriatric: Adjust dose based on renal and hepatic function, monitor for side effects.

Renal Impairment: Use with caution; adjust dose if necessary.

Hepatic Impairment: Use cautiously; hepatic metabolism may be impaired.

Pharmacokinetics

Absorption: Well absorbed orally, with bioavailability around 30-65%.

Distribution: Widely distributed into body tissues and fluids, including respiratory secretions.

Metabolism: Metabolized in the liver, primarily by CYP3A4.

Excretion: Primarily excreted in bile; small amount in urine.

Half Life: Approximately 1.5-2 hours, extended in hepatic impairment.

Contraindications

Hypersensitivity to erythromycin or other macrolides.
Concurrent use with pimozide, astemizole, terfenadine (due to risk of QT prolongation).

Precautions

Use with caution in patients with hepatic dysfunction, myasthenia gravis, or arrhythmias. Monitor for gastrointestinal disturbances, and taste disturbances.

Adverse Reactions - Common

Gastrointestinal upset (nausea, vomiting, diarrhea) (Common)
Altered taste (Less common)

Adverse Reactions - Serious

QT prolongation, torsades de pointes (Rare)
Hepatotoxicity (Rare)
Allergic reactions, including anaphylaxis (Rare)

Drug-Drug Interactions

Warfarin (increased bleeding risk) Theophylline (elevated levels)
Carbamazepine (increased levels)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor liver function tests, cardiac status (ECG if indicated), and for signs of superinfection.

Diagnoses:

Risk for QT prolongation, risk of superinfection.

Implementation: Administer with food if gastrointestinal upset occurs; monitor therapeutic response; adjust doses as needed.

Evaluation: Assess infection resolution (clinical symptoms, lab findings), monitor for adverse effects.

Patient/Family Teaching

Take full course of medication as prescribed.
Report signs of liver problems (jaundice, dark urine), cardiac symptoms (dizziness, palpitations).
Avoid concurrent use of certain medications that may prolong QT interval.

Special Considerations

Black Box Warnings:

Potential for QT prolongation and sudden death, especially with concomitant use of other QT-prolonging drugs.

Genetic Factors: None specific.

Lab Test Interference: May cause false tests for urinary catecholamines and steroids.

Overdose Management

Signs/Symptoms: Nausea, vomiting, severe gastrointestinal distress.

Treatment: Supportive care, gastric lavage, and monitoring; no specific antidote.

Storage and Handling

Storage: Store at room temperature, away from light and moisture.

Stability: Stable under recommended conditions for shelf life specified in product insert.