Chloramphenicol Side Effects

Not all side effects for chloramphenicol may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to chloramphenicol: capsule, powder for solution, suspension

In addition to its needed effects, some unwanted effects may be caused by chloramphenicol. In the event that any of these side effects do occur, they may require medical attention.

Stop taking chloramphenicol and get emergency help immediately if any of the following effects occur:

Rare - in babies only
  • Bloated stomach
  • drowsiness
  • gray skin color
  • low body temperature
  • uneven breathing
  • unresponsiveness

You should check with your doctor immediately if any of these side effects occur when taking chloramphenicol:

Less common
  • Pale skin
  • sore throat and fever
  • unusual bleeding or bruising
  • unusual tiredness or weakness (the above side effects may also occur up to weeks or months after you Stop taking chloramphenicol)
  • Confusion, delirium, or headache
  • eye pain, blurred vision, or loss of vision
  • numbness, tingling, burning pain, or weakness in the hands or feet
  • skin rash, fever, or difficulty in breathing

Some of the side effects that can occur with chloramphenicol may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common
  • Diarrhea
  • nausea or vomiting

For Healthcare Professionals

Applies to chloramphenicol: compounding powder, injectable powder for injection, oral capsule


Hematologic side effects due to chloramphenicol-induced bone marrow depression are the most significant adverse reactions and have included aplastic anemia, hypoplastic anemia, thrombocytopenia, pancytopenia, and granulocytopenia. Idiosyncratic aplastic anemia occurs in approximately 1 in 20,000 to 1 in 40,000 cases, is fatal in 70% of affected patients, and resolves in only 10% of patients. Reversible bone marrow suppression is more common, and is dose-related. Paroxysmal nocturnal hemoglobinuria has also been reported. Hemolysis may occur in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Aplastic anemia is idiosyncratic and dose-independent. It has been reported in patients who have received intravenous, oral, and topical (including ophthalmologic ointment) chloramphenicol 3 to 12 weeks after initiation of therapy.

Reversible bone marrow suppression may present as early as 5 days after therapy is begun as pancytopenia, is more common with plasma chloramphenicol levels of 25 mcg/mL or more, and may result in high serum iron levels due to lack of bone marrow clearance of iron.


Anaphylaxis may present with urticarial rash, bronchospasm, and angioedema, and is rare.

Hypersensitivity side effects have included fever, macular and vesicular rashes, angioedema, urticaria, anaphylaxis, fever, hypersensitivity myocarditis, and angioedema. Herxheimer's reactions have been reported during treatment of typhoid fever. Extremely rare cases of contact dermatitis have been reported.

Nervous system

Nervous system side effects have included headache, mental confusion, delirium, ototoxicity, sensorineural hearing loss, optic neuritis, peripheral neuritis, and encephalopathy.

Sensorineural hearing loss has been reported after oral administration and after topical administration of chloramphenicol to the outer ear. The proposed mechanism is inhibition of mitochondrial protein synthesis in highly oxidative organs.


Psychiatric side effects have included mild depression.


Gastrointestinal side effects have infrequently included nausea, vomiting, glossitis, stomatitis, and enterocolitis.


Cardiovascular side effects have rarely included cardiomyopathy. The proposed mechanism is inhibition of mitochondrial protein synthesis in highly oxidative organs.


Hepatic side effects have included rare cases of hepatitis.


Gray syndrome has been reported in neonates, premature infants, and infants. It usually appears after 3 to 4 days of chloramphenicol therapy and manifests as abdominal distension with or without vomiting, progressive pallid cyanosis, irregular respiration, vasomotor collapse, and death within a few hours after onset. In one case gray syndrome was reported in a neonate whose mother had received chloramphenicol during labor. High chloramphenicol serum levels (greater than 90 mcg/mL) have been associated with gray syndrome and large doses have been associated with a rapidly fatal course. Symptoms are frequently reversible with complete recovery if chloramphenicol is discontinued immediately.

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