Antibioptal

Uses

Chloramphenicol 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

Neomycin is an aminoglycoside antibiotic agent used orally and topically to treat a wide variety of infections in the body.

Oral neomycin sulfate is indicated as an adjunctive therapy in hepatic coma (portal-system encephalopathy) by reducing ammonia-forming bacteria in the intestinal tract. It is strongly recommended that oral neomycin is only used in infections that are proven or strongly suspected to be caused by susceptible bacteria to reduce the risk of the development of drug-resistant bacteria.

Neomycin, in combination with polymyxin B sulfates and hydrocortisone in otic suspensions, is used in the treatment of superficial bacterial infections of the external auditory canal caused by organisms susceptible to the antibiotics. This otic formulation is also used in the treatment of infections of mastoidectomy and fenestration cavities caused by organisms susceptible to the antibiotics.

The ophthalmic solution containing neomycin in combination with polymyxin B sulfates and dexamethasone is used to treat steroid-responsive inflammatory ocular conditions for which a corticosteroid is indicated and where bacterial infection or a risk of bacterial infection exists.

Antibioptal 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 disinfectionAcne pustular, Allergic Contact Dermatitis, Allergy Skin, Atopic Dermatitis (AD), Atopic Dermatitis (AD) of the external ear canal, Bacterial diarrhoea, Burns, Carbuncle, Cradle Cap, Dermatitis, Dermatitis, Contact, Dermatitis, Eczematous, Diarrhoea, Discoid Lupus Erythematosus (DLE), Ear infection bacterial, Ear infection bacterial caused by susceptible bacteria, Gastrointestinal Infections, Hepatic coma, Hidradenitis Suppurativa (HS), Hot Water Burns (Scalds), Impetigo, Impetigo contagious, Infantile Eczema, Infected Wounds, Infected skin ulcer, Infection of the outer ear caused by susceptible bacteria, Infectious diarrhea, Inflammatory Reaction caused by Acne, Intertrigo, Itching caused by Infection, Lichen Planus (LP), Localized Infection caused by susceptible bacteria, Nail infection, Neurodermatitis, Otitis Externa, Postoperative Wound Infection, Psoriasis Vulgaris (Plaque Psoriasis), Pustular Dermatosis, Radiodermatitis, Secondarily Infected Eczema, Secondary Bacterial Infection, Skin Burns, Skin Infections, Skin Infections, Bacterial, Skin Irritation, Skin Ulcer, Solar erythema, Abrasions, Blistering caused by Staphylococcus, Erythematous eruptions, Intertriginous erythema of the anogenital, Ocular bacterial infections caused by susceptible bacteria, Resistant to other corticosteroids Dermatosis, Susceptible Bacterial Infections

How Antibioptal works

Chloramphenicol 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.

Like other aminoglycoside antibiotic drugs, neomycin inhibits bacterial ribosomes by binding to the 30S ribosomal subunit of susceptible bacteria and disrupting the translational machinery of bacterial protein synthesis. Bacterial translation is normally initiated by the mRNA binding to the 30S ribosomal subunit and subsequent binding with 50S subunit for elongation.

Dosage

Antibioptal 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.

The oral LD₅₀ of neomycin sulfate in mouse is > 8 g/kg. The subcutaneous LD₅₀ is 200 mg/kg in rat and 190 mg/kg in mouse. The intraperitoneal LD₅₀ in mouse is 305 mg/kg. The oral Lowest published toxic dose (TDLo) in woman is 12600 mg/kg/7D.

Because of low absorption, acute overdosage from oral neomycin is not likely to occur. However, prolonged administration of neomycin should be avoided because of the possibility of some systemic absorption and the risk of neurotoxicity, ototoxicity, and/or nephrotoxicity. Hemodialysis will remove neomycin from the blood. While nephrotoxicity and ototoxicity have been reported in otherwise patients without compromised renal function, the risk for developing these toxicities is increased in patients with renal impairment. Like other aminoglycosides, neomycin may cause fetal harm and total irreversible bilateral congenital deafness when administered in pregnant women.

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.

Volume of Distribution

The small fraction of absorbed neomycin is rapidly distributed in the tissues. The amount of systemically absorbed neomycin is reported to increase cumulatively with each repeated dose administered until a steady state is reached.

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.

Neomycin is poorly absorbed from the gastrointestinal tract. Gastrointestinal absorption of the drug may be increased if inflammatory or ulcerative gastrointestinal disease is present.

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.

There is limited information on the half-life of neomycin.

Clearance

There is limited information on the clearance rate of neomycin.

Elimination Route

The small absorbed fraction of neomycin is excreted by the kidney. The unabsorbed portion of the drug is excreted unchanged in the feces.

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.

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