Rexaphenicol

Uses

Rexaphenicol is used for Ocular infections, Bacterial meningitis, Anaerobic bacterial infections, Anthrax, Brain abscess, Ehrlichiosis, Gas gangrene, Granuloma inguinale, Infections caused by H. influenzae, Listeriosis, Plague, Psittacosis, Q fever, Severe gastroenteritis, Severe melioidosis, Severe systemic infections with Camphylobacter fetus, Tularaemia, Whipple's disease, Otitis externa

Rexaphenicol is also used to associated treatment for these conditions: Acne, Bacterial Conjunctivitis, Bacterial Conjunctivitis caused by susceptible bacteria, Bacterial Infections, Bacterial dacryocystitis, Bacterial diarrhoea, Conjunctivitis allergic, Corneal Inflammation, Eye swelling, Keratitis bacterial, Ocular Inflammation, Trachoma, Anterior eye segment inflammation, Bacterial blepharitis, Bacterial corneal ulcers, Non-purulent ophthalmic infections caused by susceptible bacteria, Superficial ocular infections, Skin disinfection

How Rexaphenicol works

Rexaphenicol is lipid-soluble, allowing it to diffuse through the bacterial cell membrane. It then reversibly binds to the L16 protein of the 50S subunit of bacterial ribosomes, where transfer of amino acids to growing peptide chains is prevented (perhaps by suppression of peptidyl transferase activity), thus inhibiting peptide bond formation and subsequent protein synthesis.

Dosage

Rexaphenicol dosage

For Eye: Adults, children and infants (all age groups): One or two drops 4 to 6 times a day should be placed in the infected eyes. If necessary the frequency of dose can be increased. Treatment should be continued for approximately 7 days but should not be continued for more than three weeks without re-evaluation by the prescribing physician.

For Ear: 2 to 3 drops into ear canal thrice or four times daily.

Otic/Aural: Otitis externa:Instill 2-3 drops of a 5% solution into the ear bid-tid.

Oral:Bacterial meningitis, Anaerobic bacterial infections, Anthrax, Brain abscess, Ehrlichiosis, Gas gangrene, Granuloma inguinale, Infections caused by H. influenzae, Listeriosis, Plague, Psittacosis, Q fever, Severe gastroenteritis, Severe melioidosis, Severe systemic infections with Camphylobacter fetus, Tularaemia, Whipple's disease:

• Adult:50 mg/kg/day in 4 divided doses increased to 100 mg/kg/day for meningitis or severe infections due to moderately resistant organisms. Continue treatment after the patient's temperature has normalised for a further 4 days in rickettsial disease and 8-10 days in typhoid fever.
• Child:Premature and full-term neonates: 25 mg/kg/day in 4 divided doses. Full-term infants >2 wk: 50 mg/kg/day in 4 divided doses. Children: 50 mg/kg/day in 4 divided doses increased to 100 mg/kg/day for meningitis or severe infections.

Side Effects

Oral: GI symptoms; bleeding; peripheral and optic neuritis, visual impairment, blindness; encephalopathy, confusion, delirium, mental depression, headache. Haemolysis in patients with G6PD deficiency.

ophthalmic application: Hypersensitivity reactions including rashes, fever and angioedema.

Ear drops: Ototoxicity.

Toxicity

Oral, mouse: LD₅₀ = 1500 mg/kg; Oral, rat: LD₅₀ = 2500 mg/kg. Toxic reactions including fatalities have occurred in the premature and newborn; the signs and symptoms associated with these reactions have been referred to as the gray syndrome. Symptoms include (in order of appearance) abdominal distension with or without emesis, progressive pallid cyanosis, vasomotor collapse frequently accompanied by irregular respiration, and death within a few hours of onset of these symptoms.

Precaution

Impaired renal or hepatic function; premature and full-term neonates. Monitor plasma concentrations to avoid toxicity.

Interaction

Decreased effects of iron and vitamin B12 in anaemic patients. Phenobarbitone and rifampin reduce efficacy of chloramphenicol. Impairs the action of oral contraceptives.

Food Interaction

• Take on an empty stomach.

Rexaphenicol Drug Interaction

Moderate: cyanocobalamin, cyanocobalaminUnknown: aspirin, aspirin, epinephrine, epinephrine, sulfamethoxazole / trimethoprim, sulfamethoxazole / trimethoprim, glycerin, glycerin, acetaminophen, acetaminophen, valproic acid, valproic acid, pyridoxine, pyridoxine, cholecalciferol, cholecalciferol, phytonadione, phytonadione

Rexaphenicol Disease Interaction

Major: colitis, bone marrow suppression, renal/liver disease

Elimination Route

Rapidly and completely absorbed from gastrointestinal tract following oral administration (bioavailability 80%). Well absorbed following intramuscular administration (bioavailability 70%). Intraocular and some systemic absorption also occurs after topical application to the eye.

Half Life

Half-life in adults with normal hepatic and renal function is 1.5 - 3.5 hours. In patients with impaired renal function half-life is 3 - 4 hours. In patients with severely impaired hepatic function half-life is 4.6 - 11.6 hours. Half-life in children 1 month to 16 years old is 3 - 6.5 hours, while half-life in infants 1 to 2 days old is 24 hours or longer and is highly variable, especially in low birth-weight infants.

Pregnancy & Breastfeeding use

Pregnancy Category C. Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.

Contraindication

History of hypersensitivity or toxic reaction to the drug; pregnancy, lactation; porphyria; parenteral admin for minor infections or as prophylaxis; preexisting bone marrow depression or blood dyscrasias.

Storage Condition

Cap/susp: Store at temp not exceeding 30°C.

Ophth/otic preparation: Store between 2-8°C. Do not freeze. Protect from light.

Innovators Monograph

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