ERYPED
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ERYPED (ERYPED).
Erythromycin acts by binding to the 50S subunit of the bacterial ribosome, inhibiting protein synthesis by blocking the translocation step. It is a macrolide antibiotic.
| Metabolism | Erythromycin is primarily metabolized by the cytochrome P450 enzyme CYP3A4 in the liver. |
| Excretion | Primarily hepatic (biliary excretion of unchanged drug and metabolites); approximately 5% renal excretion as unchanged drug. |
| Half-life | 2-4 hours (prolonged to 4-6 hours in neonates and patients with hepatic impairment); requires q6h dosing for most indications. |
| Protein binding | 70-80% bound to serum proteins (primarily albumin). |
| Volume of Distribution | 0.5-0.7 L/kg (indicating distribution into total body water and tissues). |
| Bioavailability | Oral: 25-40% (variable, improved with enteric coating); IV: 100%. |
| Onset of Action | Oral: 1-2 hours; IV: immediate (within minutes) for antibacterial effect. |
| Duration of Action | 6-8 hours (bacteriostatic); clinical effect persists for dosing interval (q6h). |
250–500 mg orally every 6 hours or 500–1000 mg intravenously every 6 hours; maximum 4 g/day.
| Dosage form | TABLET, CHEWABLE |
| Renal impairment | GFR >50 mL/min: no adjustment; GFR 10–50 mL/min: 250–500 mg every 6 hours; GFR <10 mL/min: 250–500 mg every 8 hours. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: reduce dose by 75%. |
| Pediatric use | Children >1 month: 30–50 mg/kg/day orally divided every 6 hours; intravenously: 20–40 mg/kg/day divided every 6 hours. Maximum 4 g/day. |
| Geriatric use | No specific dose adjustment, but monitor renal function and consider reduced starting dose due to age-related decline in GFR. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ERYPED (ERYPED).
| Breastfeeding | Compatible with breastfeeding. Erythromycin is excreted into breast milk in small amounts; M/P ratio approximately 0.5. Risk of infant gastrointestinal disturbance and theoretical risk of hypertrophic pyloric stenosis (limited to cases with high maternal doses). |
| Teratogenic Risk | FDA Pregnancy Category B. Animal studies have not demonstrated teratogenic effects. No adequate and well-controlled studies in pregnant women. Erythromycin is considered low risk. First trimester: No increased risk of major malformations reported. Second and third trimesters: Use with caution; avoid estolate salt due to cholestatic hepatitis risk. |
■ FDA Black Box Warning
Erythromycin has been associated with prolongation of the QT interval and fatal arrhythmias, including torsades de pointes. Avoid use in patients with preexisting QT prolongation, electrolyte disturbances, or concurrent use of QT-prolonging drugs.
| Serious Effects |
["Hypersensitivity to erythromycin or any macrolide antibiotic","Preexisting QT interval prolongation","Concurrent use of cisapride, pimozide, or ergotamine derivatives","Hepatic impairment (for erythromycin estolate)"]
| Precautions | ["QT interval prolongation and cardiac arrhythmias","Hepatic dysfunction (especially with erythromycin estolate)","Hearing loss (especially at high doses or in renal impairment)","Exacerbation of myasthenia gravis","Bacterial or fungal overgrowth with prolonged use","Increased risk of infantile hypertrophic pyloric stenosis in neonates"] |
| Food/Dietary | Grapefruit and grapefruit juice should be avoided as they can increase erythromycin serum concentrations and risk of toxicity. High-fat meals may slightly delay absorption but not significantly affect overall exposure. No other specific food restrictions; maintain adequate hydration. |
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| Fetal Monitoring | Monitor maternal hepatic function (LFTs) due to risk of cholestatic hepatitis, especially with prolonged use or estolate salt. Assess for cardiac effects (QT prolongation) if high doses or concurrent QT-prolonging agents. In neonates, monitor for gastrointestinal disturbances and pyloric stenosis symptoms. |
| Fertility Effects | No known adverse effects on fertility in human studies. In vitro studies suggest erythromycin may affect sperm motility at high concentrations, but clinical significance is unclear. |
| Clinical Pearls | ERYPED (erythromycin) is a macrolide antibiotic with prokinetic properties; monitor for QT prolongation especially with other QT-prolonging drugs. Use caution in hepatic impairment. May increase serum levels of theophylline, warfarin, and carbamazepine via CYP3A4 inhibition. IV administration can cause thrombophlebitis; dilute appropriately and rotate sites. |
| Patient Advice | Take exactly as prescribed; do not skip doses or stop early even if you feel better. · May be taken with or without food; if GI upset occurs, take with food or milk. · Avoid grapefruit and grapefruit juice during treatment as it may increase side effects. · Report any signs of allergic reaction: rash, hives, difficulty breathing. · Notify your doctor if you experience severe diarrhea, irregular heartbeat, or hearing loss. · Do not use with other medications without consulting your doctor due to potential interactions. · Complete the full course of therapy to prevent antibiotic resistance. |