Chloramphenicol: Potent Broad-Spectrum Antibiotic Treatment
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Chloramphenicol is a bacteriostatic antibiotic with a broad spectrum of activity against both Gram-positive and Gram-negative bacteria, as well as certain other microorganisms. It functions by inhibiting bacterial protein synthesis, specifically binding to the 50S ribosomal subunit. This medication is reserved for serious infections where other antibiotics are ineffective or contraindicated, due to its potential for severe adverse effects. It is available in oral, topical, and parenteral formulations, though systemic use is heavily restricted in many countries.
Features
- Broad-spectrum activity against aerobic and anaerobic bacteria
- Effective against Rickettsia, Chlamydia, and Mycoplasma species
- Available in oral (capsules, suspension), ophthalmic, and topical formulations
- Rapid absorption and good tissue penetration, including CNS
- Bacteriostatic mechanism via inhibition of protein synthesis at 50S ribosomal subunit
Benefits
- Provides effective treatment for multidrug-resistant bacterial infections, including typhoid fever and bacterial meningitis
- High bioavailability and excellent penetration into tissues and body fluids, including cerebrospinal fluid and the eye
- Cost-effective alternative for certain severe infections in resource-limited settings
- Useful topically for superficial eye infections like bacterial conjunctivitis
- Can be life-saving in scenarios where first-line antibiotics have failed or are unavailable
Common use
Chloramphenicol is primarily used for serious infections caused by susceptible organisms. Systemic administration is reserved for life-threatening conditions such as typhoid fever, bacterial meningitis, rickettsial diseases, and brain abscesses when other antibiotics cannot be used. Topical formulations (eye drops/ointment) are commonly prescribed for bacterial conjunctivitis. It may also be used in veterinary medicine. Due to risks of bone marrow toxicity, its use is strictly limited and typically requires infectious disease specialist consultation.
Dosage and direction
Dosage varies significantly based on infection severity, patient age, renal/hepatic function, and formulation. For adults, typical oral dosage is 50 mg/kg/day divided every 6 hours for serious infections (max 4 g/day). IV administration follows similar dosing. For ophthalmic use: 1-2 drops in affected eye(s) every 3-6 hours, or a small amount of ointment applied 3-4 times daily. Pediatric dosing is weight-based. Treatment duration should be as short as possible (usually 5-14 days) to minimize toxicity risks. Always follow specific prescribing physician instructions.
Precautions
- Monitor complete blood counts before and during therapy (risk of bone marrow suppression)
- Use with caution in patients with hepatic or renal impairment (dose adjustment may be needed)
- Avoid unnecessary use; reserve for serious infections where benefits outweigh risks
- Do not use for trivial infections or prophylactically
- Pregnancy Category C: use only if potential benefit justifies potential fetal risk
- May cause gray baby syndrome in neonates; avoid use in premature infants and newborns
- Can cause optic and peripheral neuritis with prolonged use
Contraindications
- History of hypersensitivity to chloramphenicol
- Previous bone marrow suppression or blood dyscrasias from chloramphenicol
- Treatment of minor infections, prophylactic use, or viral infections
- Concomitant use with drugs that suppress bone marrow function
- Infants under 4 weeks old (except for ophthalmic use with extreme caution)
- Patients taking certain medications metabolized by CYP2C9 (potential interactions)
Possible side effect
- Bone marrow suppression (dose-related reversible anemia, or idiosyncratic fatal aplastic anemia)
- Gray baby syndrome in neonates (cardiovascular collapse, cyanosis, hypothermia)
- Gastrointestinal disturbances (nausea, vomiting, diarrhea)
- Hypersensitivity reactions (rash, fever, angioedema)
- Optic neuritis, peripheral neuritis with prolonged use
- Superinfections (including fungal overgrowth)
- Headache, depression, confusion
- For ophthalmic use: transient stinging, burning, blurred vision
Drug interaction
- Potentiates effects of oral anticoagulants (warfarin), phenytoin, tolbutamide, chlorpropamide (inhibits metabolism)
- Concurrent use with other bone marrow suppressants (e.g., chemotherapy, zidovudine) increases myelosuppression risk
- May reduce efficacy of penicillin antibiotics (antagonistic effect)
- Rifampin may decrease chloramphenicol levels
- Phenobarbital may reduce chloramphenicol efficacy
- Alcohol may cause disulfiram-like reaction
Missed dose
If a dose is missed, take it as soon as remembered unless it is almost time for the next dose. Do not double the dose to make up for a missed one. For ophthalmic formulations, apply the missed dose as soon as possible and resume regular schedule. Maintaining consistent serum levels is important for efficacy, but doubling doses increases toxicity risk. If multiple doses are missed, contact healthcare provider for guidance.
Overdose
Symptoms may include nausea, vomiting, gray baby syndrome (in infants), bone marrow suppression, and cardiovascular collapse. There is no specific antidote. Treatment is supportive: gastric lavage if recent ingestion, activated charcoal, and symptomatic management. Hemodialysis is not effective for removal. In cases of suspected overdose, immediately contact poison control (1-800-222-1222 in US) or emergency services. Hospitalization for monitoring of hematologic parameters is typically required.
Storage
Store at room temperature (15-30°C/59-86°F) in original container. Protect from light and moisture. Do not freeze. Keep oral and ophthalmic formulations tightly closed. Do not use beyond expiration date. Keep all medications out of reach of children and pets. Do not transfer capsules to other containers. For suspensions, shake well before use and discard after completion of therapy as directed.
Disclaimer
This information is for educational purposes only and does not constitute medical advice. Chloramphenicol is a potent antibiotic with serious risks and must only be used under direct supervision of a qualified healthcare professional. Never self-medicate or share prescription medications. Always follow your physician’s instructions regarding dosage, duration, and monitoring. Report any adverse effects immediately. The prescriber should carefully weigh benefits against risks, especially considering potential hematologic toxicity.
Reviews
“As an infectious disease specialist, I reserve chloramphenicol for multidrug-resistant Salmonella typhi infections in returning travelers. While effective, the hematologic monitoring requirements make it a last-resort option.” — Dr. E. Lawson, MD
“Ophthalmic chloramphenicol remains a workhorse for bacterial conjunctivitis in our clinic, with excellent efficacy and generally good tolerance. We carefully screen for allergy history.” — Ophthalmology Nurse Practitioner
“Used chloramphenicol IV for a patient with drug-resistant meningitis after failure of first-line therapy. Successful outcome, but required twice-weekly CBC monitoring throughout treatment.” — Hospital Pharmacist
“The risk of aplastic anemia, though rare, means we only use systemic chloramphenicol when no alternatives exist. Informed consent and meticulous monitoring are essential.” — Hematology Specialist