Chloramphenicol is a white to greyish-white or yellowish-white, fine crystalline powder or fine crystals, needles or elongated plates. Soluble 1 in 400 of water, 1 in 2.5 of alcohol, and 1 in 7 of propylene glycol; freely soluble in acetone and ethyl acetate; slightly soluble in ether. A 2.5% suspension in water has a pH of 4.5 to 7.5. Chemical Name: 2,2-Dichloro-N-[(R,R)--hydroxy--hydroxymethyl-4- nitrophenethyl] acetamide. Molecular Formula: C11H12Cl2N2O5
323.1
CHLOROMYCETIN ear drops contain chloramphenicol 5 mg per 1 mL of purified water with boric acid, borax and phenylmercuric nitrate as the preservative.
Chloramphenicol is a broad spectrum antibiotic originally isolated from Streptomyces venezuelae. It is primarily bacteriostatic and acts by inhibition of protein synthesis by interfering with the transfer of activated amino acids from soluble RNA to ribosomes.
Chloramphenicol is rapidly absorbed from the gastrointestinal tract when given by mouth and widely distributed throughout most body tissues and fluids. It is inactivated primarily in the liver by glucuronyl transferase and excreted mainly in the urine.
Treatment of otitis externa due to chloramphenicol sensitive organisms. May be used with caution in patients with chronic suppurative otitis media.
Perforated tympanic membrane is considered a contraindication to the use of this medication in the external ear canal. CHLOROMYCETIN ear drops are contraindicated in individuals with a history of hypersensitivity and/ or toxic reaction to chloramphenicol or any of its components.
Discontinue promptly if sensitisation or irritation occurs. Bone marrow hypoplasia, including aplastic anaemia and death, has been rarely reported following local application of chloramphenicol. Chloramphenicol should not be used when less potentially dangerous agents would be expected to provide effective treatment. The use of this antibiotic, as with other antibiotics, may result in an overgrowth of nonsusceptible organisms, including fungi. If infections caused by nonsusceptible organisms appear during therapy, its use should be discontinued and appropriate measures should be taken. In all serious infections, the topical use of chloramphenicol should be supplemented by appropriate systemic medication.
There are no studies to establish the safety of this drug in pregnancy. Systemically absorbed forms of chloramphenicol enter the foetal circulation and are distributed into breast milk. If given systemically to the mother shortly before parturition or whilst breastfeeding, chloramphenicol may cause bone marrow suppression of the neonate or the "grey baby syndrome", characterised by cyanosis and hypothermia, owing to the limited glucuronidating capacity of the newborn infant's liver. However, limited absorption following otic use at the recommended dosage is generally not expected to pose a risk to the foetus or the neonate. +
The following clinical adverse experiences have been observed with the use of chloramphenicol. More serious side effects (indicated by *) have been reported in patients sensitive to chloramphenicol and are causes for discontinuing the medication.
Blood and Lymphatic System Disorders:
blood dyscrasias have been reported in association with the use of chloramphenicol (See PRECAUTIONS)
Immune System Disorders
:
Anaphylactic reaction *, reaction to drug excipients
Skin and Subcutaneous Tissue Disorders
:
Angioedema *, urticaria *, rash vesicular and rash maculopapular *, pruritus
General Disorders and Administration Site Conditions: local irritation may include subjective symptoms of itching and burning+, fever *, similar sensitivity reactions to other materials in topical preparations also may occur, pyrexia *
Nervous system disorders:
Burning sensation
Interactions with other drugs: +
Systemically absorbed/administered forms of chloramphenicol have been known to interact with certain drugs.
Instil four drops in the affected ear(s) four times daily, or as directed by a physician. Discard the solution within one month of opening the container.
Accidental ingestion of the drug is unlikely to cause any toxicity due to the low content of antibiotic. Each mL of CHLOROMYCETIN ear drops contains 19 mg of borax / boric acid as buffer. It is advisable to keep medication out of reach of children. If accidentally ingested by infants or young children, a local Poisons Information Centre should be contacted. As there is individual variability in the pharmacokinetics of chloramphenicol in infants and children monitor plasma levels. Levels exceeding 25 micrograms/mL are frequently considered toxic.
Ear Drops, plastic dropper bottle (with tamper seals): 5 mL. Store between 2C and 8C. After dispensing, the drops may be stored below 25C for up to 1 month and should then be discarded. Protect from light.
Schedule 4.
Pfizer Australia Pty Ltd ABN 50 008 422 348 38-42 Wharf Rd WEST RYDE NSW 2114 Australia
25 August 2004