Is chloramphenicol FDA approved? A Look at Its History and Current Status

October 9, 2025 •

5 min read

First approved by the FDA in 1949, chloramphenicol was a groundbreaking broad-spectrum antibiotic. However, due to its association with severe, life-threatening side effects, including fatal aplastic anemia, its use has been heavily restricted and is subject to stringent regulations. Today, the question, 'Is chloramphenicol FDA approved?' requires a nuanced answer that reflects decades of evolving safety concerns and restrictions.

Quick Summary

Chloramphenicol was initially FDA-approved in 1949 but is no longer widely used due to severe adverse effects like aplastic anemia. Its use is now highly restricted to serious infections lacking safer alternatives, and oral capsules were voluntarily withdrawn for safety reasons. Topical formulations for eyes remain available with warnings. It is banned in food-producing animals.

Key Points

Initial Approval and Subsequent Warnings: Chloramphenicol was FDA-approved in 1949 but received a severe 'boxed warning' in 1961 due to its link with fatal aplastic anemia.
Restricted Systemic Use: The FDA limits the systemic (oral or intravenous) use of chloramphenicol to serious infections where less potentially dangerous drugs are ineffective or contraindicated.
Withdrawal of Oral Capsules: As of 2012, the FDA determined that oral chloramphenicol capsules were withdrawn for safety and effectiveness reasons and halted the approval of generic versions.
Availability of Topical Forms: Topical formulations like eye drops and ointments are still available for treating ocular infections, but they carry the same serious boxed warning as systemic forms.
Risk of Gray Baby Syndrome: Premature and newborn infants are at risk of developing 'Gray baby syndrome' from high doses due to immature liver metabolism, which can lead to circulatory collapse and death.
Ban in Food-Producing Animals: Due to the unacceptable risk of human exposure to drug residues that can cause blood disorders, chloramphenicol is banned for use in food-producing animals in the U.S.
Intensive Monitoring Required: Treatment with chloramphenicol necessitates regular monitoring with blood studies to detect signs of bone marrow suppression early.
Severe Drug Interactions: Co-administration with other bone marrow depressants is generally avoided, and it can affect the metabolism of other drugs by inhibiting the CYP450 3A4 enzyme.

From Broad Spectrum to Restricted Use: The Journey of Chloramphenicol

Chloramphenicol was first discovered in 1947 and gained FDA approval in 1949 as one of the first mass-produced broad-spectrum antibiotics. Its ability to combat a wide range of bacteria, including those responsible for typhoid fever, meningitis, and rickettsial infections, made it a valuable medical tool. However, as its use became widespread, clinicians observed a number of serious and potentially fatal adverse reactions.

By the early 1950s, a rare but life-threatening condition called aplastic anemia was linked to chloramphenicol. This led the FDA to issue a "boxed warning"—the most serious type of warning—for the drug in 1961, noting the high rate of mortality associated with the blood disorder. Subsequent actions by the FDA further restricted the drug. In 2012, the agency determined that oral capsule formulations were withdrawn from the market for reasons of safety and effectiveness, and it no longer accepts or approves generic versions of the oral capsule.

Current FDA Status and Regulations

The FDA has not completely revoked its approval for all forms of chloramphenicol. Instead, its current status reflects a strict risk-benefit analysis. The remaining approved uses are for serious infections where alternative, safer treatments are ineffective or contraindicated. Its use is limited to specific formulations and requires careful monitoring due to the potential for severe side effects. For example, topical ophthalmic preparations (eye drops and ointment) are still used for bacterial conjunctivitis and other superficial ocular infections but carry the same boxed warning about the risk of fatal aplastic anemia, though the risk is considerably lower with topical application.

For food safety reasons, the FDA banned chloramphenicol for use in all food-producing animals in the United States in 1997 due to the risk of residues accumulating and causing human blood disorders. This measure protects public health by preventing low-level, long-term exposure through the food supply.

Serious Adverse Effects and FDA Warnings

Chloramphenicol is associated with two primary and severe adverse effects that drove the FDA to impose strict restrictions and warnings. These effects highlight the drug's potent, and sometimes indiscriminate, impact on human cells.

The 'Gray Baby Syndrome'

In newborns and premature infants, high doses of chloramphenicol can cause a fatal condition known as 'Gray baby syndrome'. This occurs because their immature livers lack sufficient glucuronidation enzymes to properly metabolize and clear the drug from their systems. Symptoms, appearing 2 to 9 days after treatment begins, include a progressive ashen-gray skin coloration, abdominal distension, vomiting, hypotension, and circulatory collapse. This was a major impetus for pediatric clinical trial reform to prevent similar tragedies.

Aplastic Anemia and Bone Marrow Toxicity

The most feared side effect of chloramphenicol is fatal aplastic anemia. It involves the body's inability to produce new blood cells and can occur weeks or months after treatment has ended. This idiosyncratic reaction does not appear to be dose-related, meaning even short-term or low-dose exposure can potentially trigger it. Less severe, dose-dependent, and reversible bone marrow suppression can also occur. Because of this risk, the FDA-mandated boxed warning remains on all product labeling for human use.

Mechanism of Action and Clinical Considerations

Chloramphenicol functions as a bacteriostatic antibiotic by inhibiting bacterial protein synthesis. It does this by binding to the 50S ribosomal subunit of bacteria, which prevents the formation of peptide bonds and blocks the transfer of activated amino acids. This mechanism is very effective against many bacteria but also has consequences for mammalian cells, particularly in the bone marrow and mitochondria, which is the basis for its severe toxicity.

List of Key Clinical Considerations:

Monitoring is Essential: Regular blood tests, including complete blood counts and blood levels of the drug, are required to detect early signs of bone marrow suppression during systemic treatment.
Drug Interactions: Concomitant therapy with other bone marrow-depressing agents should be avoided. Chloramphenicol is a moderate inhibitor of the CYP450 3A4 enzyme, which can increase the plasma concentrations of other drugs metabolized by this pathway.
Limited Availability: In the U.S., oral forms for human use are no longer manufactured, and parenteral (IV) or topical forms are reserved for serious, specific, and often last-resort indications.

Comparison: Past vs. Current Use


Aspect	Past Use (Pre-1960s)	Current Use (Developed Countries)
Indications	Wide range of common and serious infections, including colds and sore throats.	Very serious infections only, when safer antibiotics are ineffective or contraindicated.
Formulations	Widely available in oral (capsules) and intravenous forms.	Oral capsules withdrawn for safety. Available as IV injection and topical eye/ear drops.
Risk Profile	Fatal side effects, though known, were not as well-established or warned against.	Risks of aplastic anemia and Gray baby syndrome are clearly documented with a black box warning.
Safety Measures	Basic monitoring; understanding of side effects evolved over time.	Intensive monitoring of blood work, especially in sensitive populations like neonates.
Veterinary Use	Used in both food-producing and companion animals.	Banned in food-producing animals; restricted use in companion animals.

Conclusion: A Cautionary Tale in Pharmacology

Yes, chloramphenicol was and in some limited forms still is, FDA approved. However, its story serves as a critical example of how our understanding of drug safety can evolve over time, leading to significant changes in medical practice. The approval history of chloramphenicol is a journey from a celebrated 'wonder drug' to a medication of last resort, with strict limitations and a profound respect for its potential for harm. Today, its systemic use is reserved for life-threatening situations, while its topical application is carefully managed. The black box warning and regulatory restrictions serve as a constant reminder of the drug's inherent dangers, and the medical community's commitment to patient safety.

Understanding the FDA's Current Position on Chloramphenicol

For both healthcare providers and patients, understanding the strict FDA position on chloramphenicol is crucial. It underscores the importance of weighing risks and benefits and adhering to the protocols and monitoring requirements that have been established over decades of experience with this potent, but dangerous, medication. This careful management ensures that the drug is used only when its life-saving potential outweighs its severe risks.

For more detailed information on specific drug regulations, please refer to the official FDA website.

Frequently Asked Questions

Yes, but its use is very restricted. It is reserved for severe infections, such as typhoid fever or meningitis, where other, safer antibiotics are not effective or are contraindicated. Topical forms like eye drops are also still in use.

Chloramphenicol is considered dangerous because of its potential for causing severe, life-threatening adverse effects, including fatal aplastic anemia and the 'Gray baby syndrome' in infants. Its use is therefore limited to specific, severe cases.

Aplastic anemia is a rare but often fatal blood disorder where the bone marrow stops producing new blood cells. This idiosyncratic reaction to chloramphenicol can occur weeks or months after treatment and is not necessarily dose-dependent.

The FDA determined that oral chloramphenicol capsules were withdrawn from the market for reasons of safety and effectiveness. Safer and equally effective antibiotic alternatives were available, and the risk of fatal aplastic anemia from oral use was considered higher than from intravenous use.

Yes, in the United States, chloramphenicol is banned for use in food-producing animals. This is to prevent human exposure to residues through the food chain, which could potentially cause serious blood disorders.

Gray baby syndrome is a toxic reaction that can occur in infants, particularly newborns and premature babies, who are treated with chloramphenicol. Due to an immature liver, the drug accumulates, causing symptoms like gray skin, abdominal distension, and circulatory collapse.

Yes, some formulations are still approved, but their use is limited. This includes intravenous powder for severe hospital-monitored infections and topical ophthalmic preparations for eye infections. A boxed warning is on all products for human use.