ERYZOLE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ERYZOLE (ERYZOLE).
Erythromycin acts by binding to the 50S subunit of the bacterial ribosome, inhibiting protein synthesis by blocking the translocation step.
| Metabolism | Primarily metabolized by hepatic CYP3A4 enzyme; forms an inactive demethylated metabolite and other active metabolites. |
| Excretion | Renal excretion of unchanged drug accounts for approximately 75% of the dose; fecal elimination is about 20%, with the remainder as biliary metabolites. |
| Half-life | Terminal elimination half-life is 4-6 hours in patients with normal renal function (creatinine clearance >60 mL/min). In severe renal impairment (CrCl <30 mL/min), half-life may extend to 12-18 hours. |
| Protein binding | Approximately 92-95% bound to albumin; binding is concentration-independent. |
| Volume of Distribution | 0.8-1.2 L/kg, indicating extensive distribution into total body water and tissues (e.g., skin, lung, liver). |
| Bioavailability | Oral: 65-75% (first-pass metabolism reduces bioavailability); Intravenous: 100%; Topical: <5% systemic absorption. |
| Onset of Action | Oral: 30-60 minutes; Intravenous: 5-15 minutes; Topical: 24-48 hours for clinical effect. |
| Duration of Action | Oral/IV: 8-12 hours; Topical: 12-24 hours after application. Duration is prolonged in renal impairment. |
| Molecular Weight | 381.42 Da |
Adults: 500 mg orally once daily for 3 consecutive days per month.
| Dosage form | GRANULE |
| Renal impairment | GFR 30-50 mL/min: No adjustment needed. GFR 10-29 mL/min: 250 mg once daily for 3 consecutive days per month. GFR <10 mL/min or dialysis: Not recommended. |
| Liver impairment | Child-Pugh A and B: No adjustment needed. Child-Pugh C: Use with caution, reduce dose by 50% (250 mg once daily for 3 consecutive days per month). |
| Pediatric use | Children (≥6 years, weight ≥15 kg): 30 mg/kg (max 500 mg) orally once daily for 3 consecutive days per month. For children <6 years or weight <15 kg, safety not established. |
| Geriatric use | No specific dose adjustment, but monitor renal function closely; consider dose reduction if GFR <30 mL/min. |
| 1st trimester | Limited human data; animal studies show teratogenicity at high doses. Avoid unless benefit outweighs risk. |
| 2nd trimester | No adequate studies; potential for fetal harm. Use only if clearly needed. |
| 3rd trimester | May cause neonatal jaundice or hemolytic anemia in G6PD-deficient infants. Avoid near term. |
Clinical note
Comprehensive clinical and safety monograph for ERYZOLE (ERYZOLE).
| Placental transfer | Crosses placenta; fetal serum levels approximately 10-20% of maternal levels. |
| Breastfeeding | Excreted in breast milk in small amounts; risk of diarrhea, rash, and sensitization in infants. Caution with breastfeeding. |
| Lactation Rating |
■ FDA Black Box Warning
Increased risk of cardiac death associated with erythromycin, especially when co-administered with strong CYP3A4 inhibitors such as verapamil, diltiazem, and certain antifungal agents.
| Serious Effects |
Hypersensitivity to erythrozole or any macrolideConcomitant use with pimozideConcomitant use with ergotamine or dihydroergotamine
| Precautions | QT prolongation and torsades de pointes; avoid in patients with prolonged QTc interval, electrolyte disturbances, or concurrent use of other QT-prolonging drugs, Hepatic dysfunction, cholestatic hepatitis, Infantile hypertrophic pyloric stenosis (IHPS) in neonates, Exacerbation of myasthenia gravis, Allergic reactions, including Stevens-Johnson syndrome, Overgrowth of nonsusceptible organisms with prolonged use, Hearing loss with high doses, especially in renal impairment |
| Food/Dietary | No significant food interactions. Avoid excessive alcohol consumption as it may increase skin flushing. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | Pregnancy Category X. Erythromycin estolate (the form in ERYZOLE) is contraindicated because it is associated with an increased risk of cardiovascular malformations, pyloric stenosis, and other fetal anomalies when used during pregnancy, particularly in the first trimester. Animal studies have demonstrated teratogenicity. The risk of major congenital malformations is highest with first-trimester exposure. |
| Fetal Monitoring | Monitor maternal liver function tests (LFTs) due to risk of cholestatic hepatitis, especially with estolate form. Fetal ultrasound for cardiac and gastrointestinal anomalies if inadvertent first-trimester exposure. Monitor infant for signs of pyloric stenosis if breastfeeding. |
| Fertility Effects | No significant effects on fertility reported in animal studies or human data. However, any drug that causes severe illness may indirectly affect reproductive function. |
| Clinical Pearls | ERYZOLE is a combination of erythromycin and benzoyl peroxide. Apply sparingly to affected areas; avoid contact with eyes and mucous membranes. May bleach hair or fabrics. Use in patients with acne vulgaris who have not responded to benzoyl peroxide or topical erythromycin alone. Do not use in patients with known hypersensitivity to macrolides or benzoyl peroxide. |
| Patient Advice | Apply a thin layer to affected skin once or twice daily as directed. · Avoid contact with eyes, lips, and inside the nose. · May cause skin irritation, redness, or peeling; use moisturizer if needed. · Benzoyl peroxide may bleach hair or colored fabrics; avoid contact with clothing and bedding. · Use sunscreen daily as this medication can increase sensitivity to sunlight. · Do not use with other topical acne products without doctor approval. · If severe irritation occurs, reduce frequency or discontinue and consult healthcare provider. |