Erythromycin Formulations and Packaging
Erythromycin is supplied in multiple oral formulations including erythromycin base (tablets and capsules), erythromycin stearate (tablets), and erythromycin ethylsuccinate (tablets, powders, and liquids), with the base form commonly available as 250 mg and 500 mg film-coated tablets. 1
Specific Tablet Formulations
The FDA-approved erythromycin base tablets are supplied as:
250 mg tablets: Pink, oval-shaped, film-coated tablets debossed with "AC39"
- Bottles of 30 (NDC 69238-1484-3)
- Bottles of 100 (NDC 69238-1484-1)
500 mg tablets: Pink, oval-shaped, film-coated tablets debossed with "AC40"
- Bottles of 30 (NDC 69238-1485-3)
- Bottles of 100 (NDC 69238-1485-1) 2
Available Salt Forms for Oral Administration
Erythromycin comes in three primary oral salt forms, each with distinct formulations:
- Erythromycin base: Tablets and capsules (including enteric-coated pellet formulations)
- Erythromycin stearate: Tablets only
- Erythromycin ethylsuccinate: Tablets, powders, and liquid suspensions 1
Parenteral Formulation
For intravenous administration, erythromycin lactobionate is available with specific stability requirements:
- Optimal dilution: 0.1-0.2 mg/mL
- High phlebitis risk (rating 3/3)
- Stability: 30 days at -20°C, 14 days at 5°C, 1 day at 25°C 3
Storage Requirements
All oral erythromycin formulations should be stored at 20° to 25°C (68° to 77°F), with excursions permitted between 15° to 30°C (59° to 86°F), and kept tightly closed. 2
Clinical Considerations
The choice between formulations matters clinically. Enteric-coated erythromycin base tablets and erythromycin ethylsuccinate liquid formulations cause less gastrointestinal intolerance compared to non-enteric coated base or stearate forms, though all forms demonstrate similar antimicrobial efficacy. 4, 5 The ethylsuccinate ester derivatives can be taken with food to minimize GI side effects. 1