OPHTHOCHLOR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for OPHTHOCHLOR (OPHTHOCHLOR).
Chloramphenicol inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing peptide bond formation.
| Metabolism | Primarily hepatic via glucuronidation; a small amount is hydrolyzed to inactive metabolites. |
| Excretion | Renal: 70-80% unchanged; biliary/fecal: 20-30% |
| Half-life | 5-6 hours in normal renal function; prolonged up to 24-48 hours in severe renal impairment |
| Protein binding | 50-60% bound to albumin |
| Volume of Distribution | 0.5-1.0 L/kg indicating distribution into total body water |
| Bioavailability | Oral: 80-90%; intravenous: 100% |
| Onset of Action | Oral: 1-2 hours; Intravenous: 10-30 minutes |
| Duration of Action | 6-8 hours after single dose; extended with renal impairment |
| Molecular Weight | 290.08 |
Chloramphenicol 0.5% ophthalmic solution: Instill 1-2 drops into the affected eye(s) every 3-4 hours for 7-10 days. For severe infections, every 2 hours initially. Ointment: Apply a small amount (about 0.5 cm) into the conjunctival sac every 3-4 hours.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | No dosage adjustment required for ophthalmic use; minimal systemic absorption. |
| Liver impairment | Contraindicated in patients with hepatic impairment due to risk of bone marrow suppression. Child-Pugh Class B or C: avoid use. |
| Pediatric use | Neonates and infants: Avoid systemic use; ophthalmic use with caution. For children >1 year: Same as adult ophthalmic dosing. For systemic infections (uncommon): 12.5-25 mg/kg IV every 6 hours; monitor blood levels. |
| Geriatric use | No specific adjustment needed for ophthalmic use. Monitor for systemic adverse effects in elderly due to potential decreased renal/hepatic function. |
| 1st trimester | Contraindicated due to risk of hemolytic anemia and gray baby syndrome; avoid. |
| 2nd trimester | Contraindicated; potential for severe adverse effects on fetus. |
| 3rd trimester | Contraindicated; risk of gray baby syndrome in neonate. |
Clinical note
Comprehensive clinical and safety monograph for OPHTHOCHLOR (OPHTHOCHLOR).
| Placental transfer | Crosses placenta; significant transfer to fetal circulation. |
| Breastfeeding | Excreted into breast milk; potential for hemolysis and hypersensitivity in infant; avoid breastfeeding. |
| Lactation Rating | L5 |
■ FDA Black Box Warning
Serious and fatal blood dyscrasias (aplastic anemia, hypoplastic anemia, thrombocytopenia, granulocytopenia) have been reported after systemic use; topical use may also carry risk.
| Serious Effects |
Hypersensitivity to chloramphenicolHistory of bone marrow suppressionPregnancyBreastfeedingNeonates (gray baby syndrome risk)Porphyria
| Precautions | Bone marrow suppression including aplastic anemia, Hypersensitivity reactions, Superinfection with prolonged use, Not for use in viral or fungal infections |
| Food/Dietary | No known food interactions. Avoid alcohol as it may reduce drug efficacy (theoretical based on systemic metabolism). |
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| Teratogenic Risk | No well-controlled studies in pregnant women. Animal reproduction studies have not been conducted. Use only if clearly needed and potential benefit justifies risk to fetus. First trimester: theoretical risk based on general principles; second and third trimesters: limited data suggest no known teratogenicity; however, systemic absorption is low. |
| Fetal Monitoring | None specifically required beyond routine prenatal care due to minimal systemic absorption. |
| Fertility Effects | No studies on fertility effects. Based on pharmacological profile, no expected impact on fertility at recommended ophthalmic doses. |
| Clinical Pearls |
| Ophthochlor (chloramphenicol 0.5% ophthalmic solution) is rarely used due to risk of aplastic anemia from systemic absorption. Reserve for serious infections when safer alternatives are ineffective. Discard solution after 2 weeks of opening due to rapid degradation. Monitor for bone marrow suppression with prolonged use. |
| Patient Advice | Do not touch the dropper tip to any surface to avoid contamination. · Apply prescribed number of drops into the affected eye(s) as directed. · Do not share this medication with others. · Report any unusual bleeding, bruising, or signs of infection to your doctor immediately. · Store at room temperature away from light and moisture. |