AUREOMYCIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AUREOMYCIN (AUREOMYCIN).
Binds to the 30S ribosomal subunit, inhibiting protein synthesis by blocking aminoacyl-tRNA binding.
| Metabolism | Not extensively metabolized; primarily excreted unchanged in urine. |
| Excretion | Renal (70% unchanged), biliary/fecal (30% as metabolites and unchanged drug) |
| Half-life | Terminal elimination half-life: 8–12 hours (prolonged in renal impairment; may extend to 20–30 hours in anuria) |
| Protein binding | 55–65% bound primarily to albumin |
| Volume of Distribution | 1.3–1.6 L/kg (exceeds total body water, indicating extensive tissue penetration) |
| Bioavailability | Oral: 30–40% (approximately); Topical: minimal systemic absorption (<5% through intact skin) |
| Onset of Action | Oral: 1–2 hours; Intravenous: 5–10 minutes after bolus; Topical: 24–48 hours for clinical improvement |
| Duration of Action | Oral: 6–8 hours; Intravenous: 12 hours (beyond MIC for sensitive organisms); Topical: sustained local effect for 12–24 hours |
| Molecular Weight | 478.88 |
250-500 mg orally every 6 hours; or 10-20 mg/kg/day intravenously divided every 12 hours
| Dosage form | OINTMENT |
| Renal impairment | CrCl 10-50 mL/min: dose every 12-18 hours; CrCl <10 mL/min: dose every 24 hours |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use |
| Pediatric use | 8-12 years: 25-50 mg/kg/day orally divided every 6 hours; intravenous: 10-20 mg/kg/day divided every 12 hours; maximum 500 mg/day |
| Geriatric use | Reduce dose by 25-50% due to age-related renal decline; monitor renal function |
| 1st trimester | Avoid in first trimester due to risk of fetal skeletal abnormalities and discoloration of teeth (tetracycline class effect). Use only if no alternative and infection is severe. |
| 2nd trimester | Avoid in second trimester, especially after 20 weeks gestation, due to risk of fetal skeletal retardation and dental discoloration. Use only if no alternative. |
| 3rd trimester | Avoid in third trimester because tetracyclines cross placenta and can cause permanent discoloration of deciduous teeth and enamel hypoplasia; also risk of maternal hepatotoxicity. |
Clinical note
Comprehensive clinical and safety monograph for AUREOMYCIN (AUREOMYCIN).
| Placental transfer | Crosses placenta readily during all trimesters; achieves 50-60% of maternal serum concentration in fetal circulation. |
| Breastfeeding | Aureomycin (chlortetracycline) is excreted into breast milk in low concentrations. Theoretical risk of dental discoloration and bone growth inhibition in the nursing infant, but less with short-term use. American Academy of Pediatrics considers tetracyclines compatible with breastfeeding due to poor absorption. Monitor infant for rash or gastrointestinal disturbances. |
■ FDA Black Box Warning
Use during tooth development (last half of pregnancy, infancy, childhood to 8 years) may cause permanent tooth discoloration or enamel hypoplasia.
| Serious Effects |
Hypersensitivity to chlortetracycline or any tetracyclineSevere hepatic dysfunctionPregnancy (especially after first trimester) except for specific indicationsLactation (long-term use)Children under 8 years of age (for systemic use due to permanent tooth discoloration)
| Precautions | May cause photosensitivity, renal toxicity (especially in patients with impaired renal function), and superinfection with prolonged use. Avoid use in children <8 years due to tooth discoloration. |
| Food/Dietary | Avoid dairy products (milk, yogurt, cheese) within 2 hours of dosing. Do not take with calcium-fortified foods or beverages. Separate from iron-rich foods or supplements by at least 2 hours. |
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| Lactation Rating | L2 (Safer) - limited data suggest low risk, compatible with short-term use. |
| Teratogenic Risk | Aureomycin (chlortetracycline) is a tetracycline antibiotic. Tetracyclines cross the placenta and may cause fetal harm. First trimester: limited data, but risk of teratogenic effects (neural tube defects, cardiovascular malformations) cannot be excluded; animal studies show embryotoxicity. Second and third trimesters: exposure may cause permanent discoloration of deciduous teeth (yellow-gray-brown) if administered after the 4th month of gestation due to deposition in developing teeth and bones. Risk of skeletal growth retardation. Avoid use during pregnancy unless no alternative. |
| Fetal Monitoring | Monitor maternal renal and hepatic function. In pregnancy, avoid use; if unavoidable, monitor fetal growth and development via ultrasound. Assess for signs of maternal hepatotoxicity, which is rare but serious. Monitor for neonatal jaundice and dental staining postpartum. |
| Fertility Effects | No specific data on chlortetracycline effects on human fertility. In animal studies, tetracyclines have been associated with impaired fertility at high doses. Effects on spermatogenesis and ovulation are not well-documented in humans. Use during pregnancy may affect fetal gonadal development theoretically, but no clinical evidence supports significant fertility impairment. |
| Clinical Pearls | Aureomycin (chlortetracycline) is a first-generation tetracycline antibiotic. It is photosensitizing; advise patients to avoid prolonged sun exposure. It chelates with divalent and trivalent cations (e.g., calcium, iron, magnesium, aluminum), reducing oral absorption. Administer on an empty stomach, at least 1 hour before or 2 hours after meals or dairy products. Monitor for suprainfections, particularly Clostridioides difficile-associated diarrhea and vaginal candidiasis. Avoid in children under 8 years of age and in pregnancy due to risk of permanent tooth discoloration and bone growth impairment. |
| Patient Advice | Take this medication on an empty stomach, at least 1 hour before or 2 hours after meals. · Avoid taking with dairy products, antacids, iron supplements, or multivitamins as they reduce absorption. · Use sunscreen and protective clothing when outdoors to prevent severe sunburn. · Complete the full course of therapy even if you feel better. · Report persistent diarrhea, vaginal itching, or skin rash to your healthcare provider. |