Ilosone (erythromycin estolate) is a well-established macrolide antibiotic indicated for the treatment of a wide range of bacterial infections. With its proven efficacy against susceptible organisms, it offers clinicians a reliable therapeutic option for respiratory, skin, and soft tissue infections, among others. This product card provides a comprehensive overview of Ilosone, detailing its features, benefits, and essential prescribing information to support informed clinical decision-making.

Features

• Active ingredient: Erythromycin estolate
• Available formulations: Tablets, capsules, oral suspension
• Standard strengths: 250 mg, 500 mg
• Pharmacologic class: Macrolide antibiotic
• Mechanism: Inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit
• Bioavailability: Enhanced ester formulation for improved oral absorption

Benefits

• Effective against a broad spectrum of Gram-positive and some Gram-positive bacteria
• Suitable for patients with penicillin allergy as an alternative therapeutic option
• Well-established safety profile with decades of clinical use
• Convenient oral administration supports outpatient treatment and adherence
• Demonstrates anti-inflammatory properties in certain respiratory conditions
• Cost-effective antibiotic choice within its class

Common use

Ilosone is commonly prescribed for the treatment of mild to moderate infections caused by susceptible strains of microorganisms. Typical indications include upper and lower respiratory tract infections such as pharyngitis, tonsillitis, acute bronchitis, and community-acquired pneumonia. It is also effective for skin and soft tissue infections including impetigo, erysipelas, and cellulitis. Additionally, Ilosone may be used for the treatment of pertussis (whooping cough), diphtheria (as an adjunct to antitoxin), and erythrasma. Some off-label uses include treatment of acne vulgaris and prophylaxis against bacterial endocarditis in penicillin-allergic patients undergoing dental procedures.

Dosage and direction

Dosage should be individualized based on the severity of infection, susceptibility of the causative organisms, and patient characteristics. For adults, the usual dosage is 250 mg every 6 hours, or 500 mg every 12 hours. For more severe infections, dosage may be increased to 4 grams daily. Pediatric dosing is based on body weight: 30-50 mg/kg/day in divided doses. For more severe infections, dosage may be doubled. Administration should occur on an empty stomach (1 hour before or 2 hours after meals) for optimal absorption, though gastrointestinal upset may necessitate administration with food. The full prescribed course should be completed even if symptoms improve earlier to prevent antibiotic resistance.

Precautions

Hepatic function should be monitored during therapy, as erythromycin estolate has been associated with reversible hepatotoxicity, characterized by elevated liver enzymes and cholestatic hepatitis. Use with caution in patients with pre-existing liver disease or impaired hepatic function. Caution is advised in patients with renal impairment; dosage adjustment may be necessary in severe cases. May prolong the QT interval; use with caution in patients with known QT prolongation, electrolyte imbalances, or those taking other QT-prolonging medications. Superinfection with nonsusceptible organisms, including fungi, may occur and require appropriate therapy. Pseudomembranous colitis has been reported with nearly all antibacterial agents and may range in severity from mild to life-threatening.

Contraindications

Ilosone is contraindicated in patients with known hypersensitivity to erythromycin or any other macrolide antibiotics. Contraindicated in patients with pre-existing liver disease or a history of erythromycin-associated hepatitis. Should not be used concomitantly with ergot derivatives, cisapride, pimozide, or terfenadine due to potential for serious cardiac adverse events. Contraindicated in patients with known QT prolongation or ventricular arrhythmias, including torsades de pointes. Not recommended for patients taking strong CYP3A4 inhibitors concurrently.

Possible side effect

Common adverse reactions include gastrointestinal disturbances: nausea (occurring in 5-10% of patients), vomiting, abdominal pain, diarrhea, and anorexia. Less frequently reported effects include skin rash, urticaria, and mild allergic reactions. Hepatic side effects may include elevated liver enzymes and, rarely, cholestatic hepatitis. Ototoxicity, manifested as reversible hearing loss, has been reported, usually at high doses or in patients with renal impairment. Cardiac effects may include QT prolongation and ventricular arrhythmias in susceptible individuals. Other reported effects include pseudomembranous colitis, pancreatitis, and reversible neutrophilia.

Drug interaction

Ilosone demonstrates significant drug interaction potential due to CYP3A4 inhibition. May increase concentrations of theophylline, carbamazepine, cyclosporine, digoxin, and warfarin, requiring monitoring and possible dosage adjustment. Contraindicated with cisapride, pimozide, and ergot alkaloids due to risk of serious cardiovascular events. May increase concentrations of statins metabolized by CYP3A4, increasing risk of rhabdomyolysis. Coadministration with oral contraceptives may reduce contraceptive efficacy. May potentiate effects of non-depolarizing neuromuscular blocking agents. Interaction with antacids, H2-receptor antagonists, and proton pump inhibitors may reduce absorption.

Missed dose

If a dose is missed, it should be taken as soon as remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped and the regular dosing schedule resumed. Patients should not double the dose to make up for a missed administration. Maintaining consistent antibiotic levels is important for therapeutic efficacy, so patients should be advised to establish a routine for medication administration. If multiple doses are missed, patients should contact their healthcare provider for guidance.

Overdose

Symptoms of overdose may include severe nausea, vomiting, diarrhea, and abdominal pain. Hepatotoxicity may occur with massive overdose. Ototoxicity, manifested as hearing loss, tinnitus, or vertigo, may be observed. Cardiac effects may include QT prolongation and ventricular arrhythmias. Treatment is primarily supportive and symptomatic. Gastric lavage may be considered if ingestion was recent. Activated charcoal may be administered. Electrolyte imbalance should be corrected, and cardiac monitoring is recommended. Hemodialysis is not effective for removal of erythromycin. Specific antidotes are not available.

Storage

Store at controlled room temperature (20-25°C or 68-77°F). Protect from light and moisture. Keep container tightly closed. Do not freeze the oral suspension. After reconstitution, the oral suspension is stable for 14 days at room temperature; do not refrigerate. Keep out of reach of children and pets. Do not use after the expiration date printed on the packaging. Do not transfer to other containers, as this may affect stability and contamination risk.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Ilosone is a prescription medication that should be used only under the supervision of a qualified healthcare professional. The prescribing physician should be consulted for specific medical advice, diagnosis, and treatment. Safety and efficacy in pediatric patients under one month of age have not been established. Use during pregnancy should be limited to cases where the potential benefit justifies the potential risk to the fetus. Nursing mothers should consult their physician before use, as erythromycin is excreted in human milk.

Reviews

Clinical studies and decades of use demonstrate Ilosone’s effectiveness in treating susceptible bacterial infections. Many clinicians appreciate its role as an alternative for penicillin-allergic patients. Some reviews note the gastrointestinal side effects as a limitation, while others highlight its cost-effectiveness and reliable spectrum of activity. The hepatotoxicity potential, while rare, is noted in post-marketing surveillance data. Overall, it remains a valuable option in the antibiotic arsenal when used appropriately for indicated infections.