Chloramphenicol Ophthalmic solution USP 5mls

Indications

• Bacterial meningitis
• Typhoid fever
• Severe rickettsial infections
• Bacterial conjunctivitis
• Infections caused by anaerobic bacteria
• Serious infections caused by susceptible strains of bacteria

Dosage

Children: Refer

Adults: Refer to current clinical guidelines and dosing references.

Mechanism of action

Chloramphenicol exerts its antibacterial effect by inhibiting bacterial protein synthesis. It specifically binds to the 50S subunit of the bacterial ribosome, blocking the peptidyl transferase activity. This action prevents the formation of peptide bonds between amino acids, ultimately leading to the cessation of bacterial growth and proliferation.

Pharmacodynamics

Chloramphenicol displays time-dependent bactericidal activity against susceptible bacteria. Its broad spectrum of activity includes many strains of Streptococcus, Staphylococcus, Hemophilus, and Neisseria species. The drug is particularly effective in treating infections caused by bacteria resistant to other antibiotics, owing to its unique mechanism of action. Resistance to chloramphenicol can occur through plasmid-encoded acetyltransferases that modify the drug, reducing its efficacy.

Pharmacokinetics

Chloramphenicol is well-absorbed from the gastrointestinal tract when administered orally, achieving peak plasma concentrations within 1 to 2 hours. It is widely distributed throughout the body, including into the central nervous system, and is highly protein-bound (approximately 50-60%). The drug is metabolized in the liver, primarily through glucuronidation, and is excreted in the urine, with a half-life of about 1 to 3 hours in healthy adults. Factors such as liver function, age, and disease state can significantly affect its pharmacokinetics.

Contra-indications

• Hypersensitivity to chloramphenicol or any component of the formulation
• Significant bone marrow depression
• Porphyria
• Severe hepatic impairment

Adverse effects

• Bone marrow suppression
• Aplastic anemia
• Gray baby syndrome
• Nausea
• Vomiting
• Diarrhea
• Rash
• Peripheral neuropathy

Interactions

• Increased risk of toxicity when used with drugs that cause bone marrow suppression (e.g., sulfonamides, methotrexate)
• Antagonistic effect with chloramphenicol and penicillin
• Inhibition of hepatic metabolism may occur with concurrent use of certain drugs (e.g., phenobarbital, phenytoin)

Precautions

• Monitor blood counts regularly, especially during prolonged therapy
• Use with caution in patients with liver dysfunction
• Not recommended for use in neonates due to the risk of gray baby syndrome
• Careful consideration should be given to pregnant women due to potential risks

Pregnancy

Chloramphenicol is classified as Pregnancy Category C. It should only be used if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Chloramphenicol is excreted in breast milk. Caution is advised when administering to nursing mothers due to the risk of serious adverse effects in breastfed infants.

Storage

Store in a cool, dry place at room temperature. Protect from light. Keep out of reach of children.

Formulations

• Chloramphenicol 250 mg capsules
• Chloramphenicol 500 mg injection
• Chloramphenicol 1% eye drops