Polymyxin B (EENT) (Monograph)

Brand name: Casporyn HC
Drug class: Antibacterials
VA class: OT101
CAS number: 1405-20-5

Introduction

Antibacterial; polymyxin antibiotic.^{102 103 105 106 125 126 127 128}

Uses for Polymyxin B (EENT)

Bacterial Ophthalmic Infections

Used in fixed combination with other anti-infectives (i.e., bacitracin; bacitracin and neomycin; neomycin and gramicidin; trimethoprim) for topical treatment of superficial infections of the eye (e.g., conjunctivitis, keratitis, keratoconjunctivitis, blepharitis, blepharoconjunctivitis) caused by susceptible bacteria.^{102 103 105 106 125 126 127 128}

Used subconjunctivally for treatment of infections of the eye caused by susceptible Pseudomonas aeruginosa.¹⁰⁴

Mild, acute bacterial conjunctivitis often resolves spontaneously without anti-infective treatment.^{135 136 137 141} Although topical ophthalmic anti-infectives may shorten time to resolution and reduce severity and risk of complications,^{135 136 137 141} avoid indiscriminate use of topical anti-infectives.^{135 141} Treatment of acute bacterial conjunctivitis generally is empiric;^{135 136 141} use of a broad-spectrum topical ophthalmic antibacterial usually recommended.^{135 136 141} In vitro staining and/or cultures of conjunctival material may be indicated in management of recurrent, severe, or chronic purulent conjunctivitis or when acute conjunctivitis does not respond to initial empiric topical treatment.^{135 136 141}

Because bacterial keratitis may be associated with subsequent loss of vision as the result of corneal scarring or topographic irregularities and because untreated or severe bacterial keratitis may result in corneal perforation with potential for endophthalmitis and possible loss of the eye, optimal management involves rapid evaluation and diagnosis, timely initiation of treatment, and appropriate follow-up.¹³⁸ Treatment of community-acquired bacterial keratitis generally is empiric;¹³⁸ use of a broad-spectrum topical ophthalmic antibacterial usually recommended.¹³⁸ Subconjunctival anti-infectives may be necessary if scleral spread or perforation is imminent.¹³⁸ In vitro staining and/or cultures of corneal material are indicated in management of keratitis involving corneal infiltrates that are central, large, and extend to the middle to deep stroma; when keratitis is chronic or unresponsive to broad-spectrum topical anti-infective treatment; or when atypical features suggest fungal, amebic, or mycobacterial infection.¹³⁸

Bacterial Otic Infections

Used in fixed combination with neomycin and a corticosteroid (i.e., hydrocortisone) for topical treatment of superficial infections of the external auditory canal (otitis externa) caused by susceptible bacteria.^{121 122 123 124 139} Also used for topical treatment of infections of mastoidectomy and fenestration cavities caused by susceptible bacteria.^{121 124}

Diffuse, uncomplicated acute otitis externa in otherwise healthy patients usually treated initially with topical therapy (e.g., otic anti-infective or antiseptic with or without an otic corticosteroid).^{139 143} Supplement with systemic anti-infective therapy if patient has a medical condition that could impair host defenses (e.g., diabetes mellitus, HIV infection) or if infection has spread into pinna, skin of the neck or face, or into deeper tissues such as occurs with malignant otitis externa.¹³⁹ Malignant otitis externa is an invasive, potentially life-threatening infection, especially in immunocompromised patients, and requires prompt diagnosis and treatment with systemic anti-infectives.¹³⁹

Ocular Inflammation

Fixed-combination ophthalmic preparations containing polymyxin B, neomycin, and dexamethasone^{119 120} or fixed-combination ophthalmic preparations containing polymyxin B, neomycin, bacitracin, and hydrocortisone or hydrocortisone acetate^{107 108} are used for topical treatment of corticosteroid-responsive ocular conditions when a corticosteroid is indicated and superficial bacterial ocular infection or risk of such infection exists.^{107 108 119 120}

Although manufacturers state that use of fixed-combination ophthalmic preparations containing anti-infectives and a corticosteroid may be indicated in ocular inflammatory conditions when risk of superficial ocular infection is high or when potentially dangerous numbers of bacteria are expected to be present in the eye,^{107 108 119 120} experts state avoid use of such preparations in patients with bacterial conjunctivitis because of risk of potentiating the infection.¹³⁶

Consider that use of fixed-combination ophthalmic preparations containing anti-infectives and a corticosteroid may mask clinical signs of bacterial, fungal, or viral infections; prevent recognition of ineffectiveness of the anti-infective; and/or increase IOP.^{107 108 119 120} (See Use of Fixed Combinations Containing Corticosteroids under Cautions.)

Polymyxin B (EENT) Dosage and Administration

Administration

Ophthalmic Administration (Topical)

Fixed combination of polymyxin B and bacitracin with or without neomycin: Apply topically to eye as an ophthalmic ointment.^{102 103 105 106}

Fixed combination of polymyxin B, neomycin, and gramicidin: Apply topically to eye as an ophthalmic solution.^{125 126}

Fixed combination of polymyxin B and trimethoprim: Apply topically to eye as an ophthalmic solution.^{127 128}

Fixed combination of polymyxin B, other anti-infectives (i.e., neomycin with or without bacitracin), and a corticosteroid (i.e., dexamethasone, hydrocortisone, or hydrocortisone acetate): Apply topically to eye as ophthalmic ointments or suspensions.^{107 108 119 120}

For topical ophthalmic use only;^{103 105 106 107 108 119 120 125 126 127 128} do not inject subconjunctivally or directly into anterior chamber of the eye.^{103 105 106 107 108 119 120 125 126 127 128}

Avoid contaminating container tip with material from eye, eyelids, fingers, or other source.^{103 105 106 107 108 119 120 125 126 127 128}

Ophthalmic Administration (Subconjunctival)

Has been administered by subconjunctival injection.¹⁰⁴

For subconjunctival administration, reconstitute vial containing sterile powder for injection (500,000 units of polymyxin B) by adding 20–50 mL of sterile water for injection or 0.9% sodium chloride injection to provide a solution containing 10,000–25,000 units/mL.¹⁰⁴ Administer appropriate dose of reconstituted solution by subconjunctival injection.¹⁰⁴

Otic Administration

Fixed combination of polymyxin B, neomycin, and hydrocortisone: Apply topically into ear canal as an otic solution or suspension.^{121 122 123 124}

Otic preparations are for topical otic use only;^{121 122 123 124} do not use in the eyes.^{122 123 124}

Clean and dry ear canal prior to administration.^{121 122 123 124}

Shake otic suspensions well prior to each use.^{121 124}

Lie with the affected ear upward.^{121 122 123 124} Instill appropriate amount of otic solution or suspension into ear; maintain this position for 5 minutes to facilitate penetration into ear canal.^{121 122 123 124} Repeat procedure for opposite ear if necessary.^{121 122 123 124}

If ear canal is narrow or edematous and there are concerns that drug delivery might be impeded,¹³⁹ consider inserting cotton wick into ear canal and saturating it with the otic preparation.^{121 122 123 124} Manufacturers state keep wick moist by adding additional otic solution or suspension every 4 hours and replace wick once every 24 hours.^{121 122 123 124} Experts state that wick unnecessary after ear canal edema subsides, which may occur within 24 hours or a few days after topical treatment initiated.¹³⁹

Avoid contaminating container tip with material from ear, fingers, or other source.^{121 122 123 124}

Dosage

Available as polymyxin B sulfate; potency and dosage expressed in terms of polymyxin B activity (units of polymyxin B).^{102 103 104 105 106 107 108 119 120 121 122 123 124 125 126 127 128}

Pediatric Patients

Bacterial Ophthalmic Infections

Ophthalmic

Polymyxin B and trimethoprim in infants and children ≥2 months of age (ophthalmic solution): Instill 1 drop in affected eye(s) every 3 hours (maximum of 6 doses daily) for 7–10 days.^{127 128}

Usual duration of topical anti-infective treatment for bacterial conjunctivitis is 5–10 days;^{135 136 141} 5–7 days usually adequate for mild bacterial conjunctivitis.¹³⁵

Bacterial Otic Infections

Otic

Polymyxin B, neomycin, and hydrocortisone in children ≥2 years of age (otic solution or suspension): Instill 3 drops in affected ear(s) 3 or 4 times daily for up to 10 days.^{121 122 123 124}

Optimal duration of topical treatment of acute otitis externa not determined, but 7–10 days usually recommended.¹³⁹ Appropriate treatment should result in improvement in symptoms (otalgia, pruritus, fullness) within 48–72 hours, although resolution of symptoms may take up to 2 weeks.¹³⁹

Ocular Inflammation

Ophthalmic

Polymyxin B, neomycin, and dexamethasone in children ≥2 years of age (ophthalmic suspension): Instill 1 or 2 drops in conjunctival sac of affected eye(s) up to 4–6 times daily.¹²⁰ In severe disease, instill 1 or 2 drops every hour initially, then taper dosage by decreasing frequency of administration as inflammation subsides.¹²⁰

If no improvement after 48 hours, reevaluate patient.^{107 108} (See Use of Fixed Combinations Containing Corticosteroids under Cautions.)

Adults

Bacterial Ophthalmic Infections

Ophthalmic (Topical)

Polymyxin B and bacitracin with or without neomycin (ophthalmic ointment): Apply to affected eye(s) every 3 or 4 hours for 7–10 days, depending on severity of infection.^{102 103 105 106}

Polymyxin B, neomycin, and gramicidin (ophthalmic solution): Instill 1 or 2 drops in affected eye(s) every 4 hours for 7–10 days.^{125 126} May instill up to 2 drops every hour for severe infections.^{125 126}

Polymyxin B and trimethoprim (ophthalmic solution): Instill 1 drop in affected eye(s) every 3 hours (maximum of 6 doses daily) for 7–10 days.^{127 128}

Usual duration of topical anti-infective treatment for bacterial conjunctivitis is 5–10 days;^{135 136 141} 5–7 days usually adequate for mild bacterial conjunctivitis.¹³⁵

Ophthalmic (Subconjunctival)

Up to 100,000 units daily using reconstituted solution containing 10,000–25,000 units/mL.¹⁰⁴

If used in conjunction with topical polymyxin B, total dosage should not exceed 25,000 units/kg daily.¹⁰⁴

Bacterial Otic Infections

Otic

Polymyxin B, neomycin, and hydrocortisone (otic solution or suspension): Instill 4 drops in affected ear(s) 3 or 4 times daily for up to 10 days.^{121 122 123 124}

Optimal duration of topical treatment of acute otitis externa not determined, but 7–10 days usually recommended.¹³⁹ Appropriate treatment should result in improvement in symptoms (otalgia, pruritus, fullness) within 48–72 hours, although resolution of symptoms may take up to 2 weeks.¹³⁹

Ocular Inflammation

Ophthalmic

Polymyxin B, neomycin, and dexamethasone (ophthalmic ointment): Apply approximately 1.25 cm (½ inch) of ointment in conjunctival sac of affected eye(s) up to 3 or 4 times daily.¹¹⁹

Polymyxin B, neomycin, and dexamethasone (ophthalmic suspension): Instill 1 or 2 drops in conjunctival sac of affected eye(s) up to 4–6 times daily.¹²⁰ In severe disease, instill 1 or 2 drops every hour initially, then taper dosage by decreasing frequency of administration as inflammation subsides.¹²⁰

Polymyxin B, neomycin, bacitracin, and hydrocortisone or hydrocortisone acetate (ophthalmic ointment): Apply to affected eye(s) every 3 or 4 hours, depending on severity of the condition.^{107 108}

If no improvement after 48 hours, reevaluate patient.^{107 108} (See Use of Fixed Combinations Containing Corticosteroids under Cautions.)

Prescribing Limits

Pediatric Patients

Bacterial Ophthalmic Infections

Ophthalmic

Polymyxin B and trimethoprim in infants and children ≥2 months of age (ophthalmic solution): Maximum 6 doses in 24 hours.^{127 128}

Bacterial Otic Infections

Otic

Polymyxin B, neomycin, and hydrocortisone in children ≥2 years of age (otic solution or suspension): Maximum 10 consecutive days of therapy.^{121 122 123 124}

Adults

Bacterial Ophthalmic Infections

Ophthalmic

Polymyxin B and trimethoprim (ophthalmic solution): Maximum 6 doses in 24 hours.^{127 128}

Bacterial Otic Infections

Otic

Polymyxin B, neomycin, and hydrocortisone (otic solution or suspension): Maximum 10 consecutive days of therapy.^{121 122 123 124}

Special Populations

No special population dosage recommendations.^{102 103 105 106 125 126 127 128}

Cautions for Polymyxin B (EENT)

Contraindications

• Polymyxin B: Hypersensitivity to polymyxins.¹⁰⁴

• Fixed combinations of polymyxin B and other anti-infectives (ophthalmic): Hypersensitivity to any ingredient in the formulation.^{102 103 105 106 125 126 127 128}

• Fixed combinations of polymyxin B, other anti-infectives, and dexamethasone, hydrocortisone, or hydrocortisone acetate (ophthalmic): Hypersensitivity to any ingredient in the formulation.^{107 108 119 120} Also, viral diseases of the cornea and conjunctiva (e.g., epithelial herpes simplex keratitis [dendritic keratitis], vaccinia, varicella), mycobacterial infections of the eye, or fungal diseases of ocular structures.^{107 108 119 120}

• Fixed combinations of polymyxin B, neomycin, and hydrocortisone (otic): Hypersensitivity to any ingredient in the formulation.^{121 122 123 124} Also, viral infections of external ear canal (e.g., herpes simplex, vaccinia, varicella zoster).^{121 122 123 124}

Warnings/Precautions

Sensitivity Reactions

Hypersensitivity Reactions

Local irritation and allergic reactions reported;^{103 105 106 107 108 119 120 121 122 123 124 125 126 127 128} more serious hypersensitivity reactions, including anaphylaxis, reported rarely.^{103 105 106 107 108 119 120 125 126 127 128}

Topical anti-infectives, particularly neomycin, may cause cutaneous sensitization.^{103 105 106 107 108 119 120 121 122 123 124 125 126}

During long-term use, periodically examine patient for signs of sensitization.^{103 105 106 107 108 121 122 123 124 125 126}

Ophthalmic preparations: Sensitization may manifest as rash, pruritus, edema of the conjunctiva and eyelid, conjunctival erythema, or failure to heal.^{103 105 106 107 108 125 126 127 128}

Otic preparations: Sensitization may manifest as swelling, dry scaling, pruritus, or failure to heal.^{121 122 123 124}

If signs or symptoms of sensitivity occur, discontinue the drug.^{103 105 106 107 108 121 122 123 124 125 126 127 128} Symptoms usually subside quickly after preparation discontinued.^{103 105 106 107 108 121 122 123 124 125 126}

Patients allergic to one fixed-combination preparation should avoid preparations containing any of the component drugs.^{103 105 106 107 108 121 122 123 124 125 126} Cross-allergenicity occurs among the aminoglycosides;^{119 120} patients allergic to fixed-combination preparations containing neomycin may also be allergic to other aminoglycosides (e.g., gentamicin, paromomycin, streptomycin).^{103 105 106 107 108 121 122 123 124 125 126}

Sulfite Sensitivity

Some fixed-combination otic preparations contain potassium metabisulfite,^{122 123} a sulfite that can cause allergic-type reactions (including anaphylaxis and life-threatening or less severe asthmatic episodes) in certain susceptible individuals.^{111 112 113 114 115 116 117 118 122 123}

Superinfection

Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi.^{102 103 104 105 106 121 122 123 124 125 126 127 128} If superinfection occurs, institute appropriate therapy.^{102 103 105 106 125 126 127 128}

Resistance to polymyxin B or other anti-infectives in fixed-combination preparations may develop.^{103 105 106 125 126}

Precautions Related to Ophthalmic Administration

Bacterial keratitis has developed in patients who inadvertently contaminated the multiple-dose container of their ophthalmic preparation; in most reported cases, concurrent corneal disease or disruption of ocular epithelial surface was present.^{103 105 106 107 108}

Do not wear contact lenses if any signs or symptoms of ocular infection are present.^{127 128}

Manufacturers caution that ophthalmic ointments may delay healing.^{102 103 105 106 107 108}

Precautions Related to Otic Administration

Do not use fixed-combination otic preparations containing polymyxin B, neomycin, and hydrocortisone in patients with perforated tympanic membrane.^{121 122 123 124}

Neomycin, especially with prolonged use, can induce permanent sensorineural hearing loss due to cochlear damage, mainly destruction of hair cells in the organ of Corti.^{121 122 123 124} Use otic preparations containing neomycin only under close clinical observation; do not use for longer than 10 consecutive days.^{121 122 123 124}

If otic infection not improved after 1 week of treatment, obtain cultures to guide treatment.^{121 122 123 124}

Use of Fixed Combinations Containing Corticosteroids

When ophthalmic or otic preparations containing polymyxin B in fixed combination with other anti-infectives and a corticosteroid (i.e., dexamethasone, hydrocortisone, hydrocortisone acetate) are used, consider cautions, precautions, and contraindications associated with EENT corticosteroids.^{107 108 119 120 121 122 123 124}

Provide initial prescriptions for fixed-combination ophthalmic preparations containing a corticosteroid or renewal prescriptions (beyond 8 g of ophthalmic ointment or beyond 20 mL of ophthalmic suspension) only after examining patient with slit lamp microscopy and, when appropriate, fluorescein staining.^{107 108 119 120}

Reevaluate patient if eye pain or inflammation persists for >48 hours or becomes aggravated.^{108 119 120}

Prolonged use of ophthalmic preparations containing a corticosteroid may result in glaucoma, with optic nerve damage, defects in visual acuity and fields of vision, and posterior subcapsular cataract formation.^{107 108 119 120} If used for ≥10 days, monitor IOP regularly, even though monitoring may be difficult in children and uncooperative patients.^{107 108 119 120} Use with caution in patients with glaucoma; check IOP frequently in such patients.^{107 108 119 120}

Use after cataract surgery may delay healing and increase incidence of bleb formation.^{107 108 119 120}

Corneal and scleral thinning reported with various ocular diseases and with long-term use of topical ophthalmic corticosteroids.^{108 120} Use in patients with thin corneal and scleral tissue may result in perforation.^{107 108 119 120}

Prolonged use may suppress host responses and increase risk of secondary ocular infections.^{107 108 119 120} Use in patients with acute purulent conditions of the eye may mask infection or enhance existing infection.^{107 108 119 120}

May prolong course and exacerbate severity of many viral infections of the eye (including herpes simplex).^{107 108 119 120} Use great caution in patients with herpes simplex; frequent slit lamp microscopy recommended.^{107 108 119 120}

Consider possibility of fungal infections of the cornea after prolonged use,^{107 108 119 120} especially in those with persistent corneal ulceration.^{119 120} Perform fungal cultures when appropriate.^{107 108 119 120}

Specific Populations

Pregnancy

Not known whether ophthalmic preparations containing polymyxin B can cause fetal harm when administered to pregnant women.^{103 105 106 125 126}

Polymyxin B and bacitracin with or without neomycin (ophthalmic): Use during pregnancy only if clearly needed.^{103 105 106}

Polymyxin B, neomycin, and gramicidin (ophthalmic): Use during pregnancy only if clearly needed.^{106 125 126}

Polymyxin B and trimethoprim (ophthalmic): Use during pregnancy only if potential benefits justify potential risks to fetus; trimethoprim may interfere with folic acid metabolism.^{127 128}

Polymyxin B, other anti-infectives, and dexamethasone, hydrocortisone, or hydrocortisone acetate (ophthalmic): Use during pregnancy only if potential benefits justify potential risks to fetus.^{107 108 119 120}

Polymyxin B, neomycin, and hydrocortisone (otic): Use during pregnancy only if potential benefits justify potential risks to fetus.^{121 122 123 124}

Lactation

Polymyxin B and other anti-infectives (ophthalmic): Use with caution.^{103 105 106 125 126 127 128}

Polymyxin B, neomycin, and dexamethasone (ophthalmic): Use with caution.^{119 120}

Polymyxin B, neomycin, bacitracin, and hydrocortisone or hydrocortisone acetate (ophthalmic): Discontinue nursing or the drug, taking into account importance of the drug to the woman.^{107 108}

Polymyxin B, neomycin, and hydrocortisone (otic): Use with caution.^{121 122 123 124}

Pediatric Use

Polymyxin B and bacitracin with or without neomycin (ophthalmic): Safety and efficacy not established in pediatric patients.^{103 105 106}

Polymyxin B, neomycin, and gramicidin (ophthalmic): Safety and efficacy not established in pediatric patients.^{125 126}

Polymyxin B and trimethoprim (ophthalmic): Safety and efficacy not established in infants <2 months of age.^{127 128}

Polymyxin B, neomycin, and dexamethasone (ophthalmic): Safety and efficacy of the suspension not established in children <2 years of age;¹²⁰ safety and efficacy of the ointment not established in pediatric patients.¹¹⁹

Polymyxin B, neomycin, bacitracin, and hydrocortisone or hydrocortisone acetate (ophthalmic): Safety and efficacy not established in pediatric patients.^{107 108}

Polymyxin B, neomycin, and hydrocortisone (otic): Most manufacturers state safety and efficacy not established in children <2 years of age because of insufficient data.^{122 123 124} One manufacturer states safety and efficacy have been established in pediatric patients and does not specify an age range.¹²¹

Geriatric Use

Polymyxin B, neomycin, and gramicidin (ophthalmic): Clinical data insufficient to determine whether geriatric patients respond differently than younger adults.¹²⁵

Polymyxin B and trimethoprim (ophthalmic): No overall differences in safety or efficacy relative to younger adults.^{127 128}

Polymyxin B, neomycin, and dexamethasone (ophthalmic): No overall differences in safety or efficacy relative to younger patients.^{119 120}

Polymyxin B, neomycin, bacitracin, and hydrocortisone acetate (ophthalmic): No overall differences in safety or efficacy relative to younger adults.¹⁰⁸

Polymyxin B, neomycin, and hydrocortisone (otic): Clinical data insufficient to determine whether geriatric patients respond differently than younger patients; other clinician experience has not identified differences in response.^{121 122 123 124}

Common Adverse Effects

Local irritation and allergic reactions.^{103 105 106 107 108 119 120 121 122 123 124 125 126 127 128}

Polymyxin B (EENT) Pharmacokinetics

Absorption

Bioavailability

Minimal or no absorption from intact or denuded skin or from mucous membranes.^a

Stability

Storage

Ophthalmic

Ointment

Polymyxin B and bacitracin: 15–25°C.^{102 103}

Polymyxin B, neomycin, and bacitracin: 15–25°C.^{105 106}

Polymyxin B, neomycin, and dexamethasone: 2–25°C.¹¹⁹ Contains methylparaben and propylparaben as preservatives.¹¹⁹

Polymyxin B, neomycin, bacitracin, and hydrocortisone or hydrocortisone acetate: 15–25°C.^{107 108}

Solution

Polymyxin B, neomycin, and gramicidin: 15–25°C;^{125 126} protect from light.¹²⁵ Contains thimerosal as a preservative.^{125 126}

Polymyxin B and trimethoprim: 15–25°C; protect from light.^{127 128} Contains benzalkonium chloride as a preservative.^{127 128}

Suspension

Polymyxin B, neomycin, and dexamethasone: 8–25°C; store upright.¹²⁰ Contains benzalkonium chloride as a preservative.¹²⁰

Powder for Injection

Polymyxin B: 20–25°C; protect from light.¹⁰⁴

After reconstitution, store at 2–8°C; discard unused portions after 72 hours.¹⁰⁴

Otic

Solution or Suspension

Polymyxin B, neomycin, and hydrocortisone: 15–25°C.^{121 122 123 124} Solutions contain potassium meta bisulfite as a preservative (see Sulfite Sensitivity under Cautions);^{122 123} suspensions contain thimerosal as a preservative.^{121 124}

Actions and Spectrum

• Polymyxin antibiotic derived from Bacillus polymyxa.^a

• Usually bactericidal.^a Increases permeability of the bacterial cell wall membrane by interacting with phospholipid components of the cell membrane.^a

• Polymyxin B: Spectrum of activity includes many aerobic gram-negative bacteria.^a Inactive against gram-positive bacteria and fungi.

• Polymyxin B in fixed combination with neomycin: Active against Staphylococcus aureus, Escherichia coli, Haemophilus influenzae, Enterobacter, Klebsiella, Neisseria, and Pseudomonas aeruginosa.^{119 120 121 122 123 124} Does not provide coverage against streptococci (including Streptococcus pneumoniae) or Serratia marcescens.^{119 120 121 122 123 124}

• Polymyxin B in fixed combination with bacitracin with or without neomycin: Active against S. aureus, streptococci (including S. pneumoniae), E. coli, H. influenzae, Enterobacter, Klebsiella, Neisseria, and Ps. aeruginosa.^{105 106 107 108} Does not provide coverage against S. marcescens.^{105 106 107 108}

• Polymyxin B in fixed combination with neomycin and gramicidin: Active against S. pneumoniae, E. coli, H. influenzae, Enterobacter, Klebsiella, Neisseria, and Ps. aeruginosa.^{125 126} Does not provide coverage against S. marcescens.^{125 126}

• Polymyxin B in fixed combination with trimethoprim: Active against S. aureus, S. epidermidis, S. pneumoniae, viridans streptococci, H. influenzae, and Ps. aeruginosa.^{127 128}

• Bacteria resistant to polymyxin B may emerge in patients receiving topical preparations containing the drug.^{103 105 106 125 126}

• Complete cross-resistance occurs between polymyxin B and colistin.^a

• Advise patients to avoid contaminating container tip with material from eye, eyelid, ears, fingers, or other source.^{103 105 106 107 108 119 120 121 122 123 124 125 126 127 128} Importance of not sharing ophthalmic or otic preparations with others^{103 105 106 107 108 119 120 125 126}

• Inform patients that serious eye damage and subsequent vision loss may occur if ophthalmic preparations are handled improperly and become contaminated by common bacteria known to cause ocular infections.^{103 105 106 107}

• Inform patients that their vision may be temporarily blurred after administration of topical ophthalmic preparations;^{119 120} take care in operating machinery or driving a motor vehicle.^{119 120}

• Importance of not wearing contact lenses if any signs or symptoms of eye infection are present.^{127 128}

• Advise patients to immediately discontinue therapy and contact a clinician if any signs of sensitivity or allergic reaction (e.g., rash, pruritus, swelling, redness) occur or if the condition worsens or does not improve.^{103 105 106 107 108 121 122 123 124 125 126 127 128}

• Advise patients using fixed-combination ophthalmic preparations containing a corticosteroid to discontinue the drug and contact a clinician if inflammation or pain persists for >48 hours or becomes aggravated.^{108 119 120}

• Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as any concomitant illnesses.^{103 105 106 107 108 119 120 121 122 123 124 125 126 127 128}

• Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.^{103 105 106 107 108 119 120 121 122 123 124 125 126 127 128}

• Importance of informing patients of other important precautionary information.^{103 105 106 107 108 119 120 121 122 123 124 125 126 127 128} (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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