Polymyxin B


Concise Prescribing Info
Indications/Uses
Listed in Dosage.
Dosage/Direction for Use
Adult : IV Susceptible infections 15,000-25,000 U/kg/day by continuous IV drip or intermittent infusion 12 hrly. Max: 2,000,000 U/day. IM Susceptible infections 25,000-30,000 U/kg/day in divided doses 4-6 hrly. Max: 2,000,000 U/day. Intrathecal Meningitis 50,000 U once daily for 3-4 days, then on alternate days for at least 2 wk. Max: 2,000,000 U/day. Subconjunctival Ocular infections Up to 100,000 U/day. Ophth Ocular infections As soln/oint w/ neomycin and dexamethasone: Soln: Instill 1-2 drops into affected eye up to 6 times/day, or hrly in severe cases. Oint: Apply a small amount into the conjunctival sac(s) up to 3-4 times/day. Otic Otic infections As otic susp containing 3.5 mg neomycin base, 10,000 U and 10 mg hydrocortisone: Instill 4 drops into the affected ear canal 3-4 times/day for up to 10 days. Topical Skin infections As 0.1% soln or oint in combination other drugs: Apply onto affected area 1-3 times/day.
Dosage Details
Intramuscular
Susceptible infections
Adult: 25,000-30,000 U/kg daily in divided doses 4-6 hrly. Max: 2,000,000 U/day.
Child: <2 yr 40,000 U/kg daily in divided doses 6 hrly (not routinely recommended due to pain at injection sites); ≥2 yr Same as adult dose but not routinely recommended due to pain at injection sites.

Intrathecal
Meningitis
Adult: 50,000 U once daily for 3-4 days, then on alternate days for at least 2 wk after CSF cultures are negative and CSF glucose content is normal. Max: 2,000,000 U/day.
Child: <2 yr 20,000 U once daily for 3-4 days or 25,000 U on alternate days, followed by the latter dose for at least wk after CSF cultures are negative and CSF glucose content is normal; ≥2 yr Same as adult dose.

Intravenous
Susceptible infections
Adult: 15,000-25,000 U/kg daily by continuous IV drip or intermittent infusion 12 hrly at 60-120 min duration. Max: 2,000,000 U/day.
Child: <2 yr 40,000 U/kg daily in divided doses 12 hrly; ≥2 yr Same as adult dose.

Ophthalmic
Ocular infections
Adult: As soln/oint w/ neomycin and dexamethasone: Soln: Instill 1-2 drops into affected eye up to 6 times daily, may be used hrly in severe cases. Oint: Apply a small amount into the conjunctival sac(s) up to 3-4 times daily.
Child: Same as adult dose.

Otic/Aural
Otic infections
Adult: As otic susp containing 3.5 mg neomycin base, 10,000 U and 10 mg hydrocortisone: Instill 4 drops into the affected ear canal 3-4 times daily for up to 10 days.
Child: As otic susp containing 3.5 mg neomycin base, 10,000 U and 10 mg hydrocortisone: Instill 3 drops into the affected ear canal 3-4 times daily for up to 10 days.

Subconjunctival
Ocular infections
Adult: Up to 100,000 U daily.

Topical/Cutaneous
Skin infections
Adult: As 0.1% soln or oint in combination other drugs: Apply onto affected area 1-3 times daily.
Child: Same as adult dose.
Renal Impairment
Intramuscular, Intravenous, Intrathecal:
Reduce dose. Max: 15,000 U/kg/day.
Reconstitution
Intravenous:
Dissolve 500,000 U in 300-500 mL of D5W for continuous IV drip, or intermittent infusion.
Intramuscular:
Dissolve 500,000 U in 2 mL sterile water for inj or NaCl 0.9% inj or 1% procaine HCl inj.
Intrathecal:
Dissolve 500,000 U in 10 mL NaCl 0.9% inj for 50,000 U/mL dosage unit.
Subconjunctival:
Dissolve 500,000 U in 20-50 mL sterile water for inj or NaCl 0.9% inj for a 10,000-25,000 U/mL concentration.
Incompatibility
Cloxacillin.
Contraindications
Hypersensitivity to polymyxins; perforated ear drums (otic). Concurrent use w/ nephrotoxic and/or neurotoxic drugs and neuromuscular blockers.
Special Precautions
Patients w/ pre-existing nitrogen retention. Renal impairment. Pregnancy and lactation.
Adverse Reactions
Facial flushing, fever, rash, pruritus, urticaria, skin exanthema, eosinophilia, dizziness, ataxia; severe pain at inj sites (IM), thrombophlebitis (IV) at inj sites. Ophth: ocular discomfort, keratitis, eye irritation.
Potentially Fatal: Nephrotoxicity, neurotoxicity (higher doses or in patients w/ renal impairment); resp paralysis, anaphylaxis, Clostridium difficile-associated diarrhoea and pseudomembranous colitis.
Ophth/Otic/Topical: C (FDA pregnancy category C applies to polymyxin B in combination w/ other drugs.)
Patient Counseling Information
Eye drop/oint may cause temporary blurred vision or other visual disturbances which may affect ability to drive or operate machinery.
MonitoringParameters
Monitor renal function; neurologic symptoms; signs of superinfection.
Drug Interactions
Potentially Fatal: Additive neurotoxic or nephrotoxic effect w/ bacitracin, streptomycin, neomycin, kanamycin, gentamicin, tobramycin, amikacin, cephaloridine, paromomycin, viomycin, colistin. Increased risk of resp paralysis w/ neuromuscular blockers (e.g. anaesthetics, muscle relaxants).
Action
Description: Polymyxin B disrupts the bacterial cytoplasmic membrane of mostly gm-ve organisms allowing leakage of intracellular constituents by binding to membrane phospholipids.
Pharmacokinetics:
Absorption: Minimal from the GI tract except in infants (≤10% of a dose). Time to peak plasma concentration: W/in 2 hr (IM).
Distribution: Widely distributed; extensively bound to cell membranes in the tissues. Plasma protein binding: Low.
Excretion: Via urine (approx 60% as unchanged drug). Half-life: 6 hr.
Chemical Structure

Chemical Structure Image
Polymyxin B

Source: National Center for Biotechnology Information. PubChem Database. Polymyxin b, CID=49800004, https://pubchem.ncbi.nlm.nih.gov/compound/Polymyxin-b (accessed on Jan. 21, 2020)

Storage
Powd for inj: Store between 20-25°C. Protect from light. Reconstituted soln: Store between 2-8°C, stable for 72 hr. Do not store in alkaline soln. Ophth soln/oint: Store below 25°C. Otic soln: Store between 15-25°C. Topical soln/oint: Store between 15-25°C.
References
Anon. Polymyxin B. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 16/06/2015.

Bacitracin Zinc, Neomycin Sulfate and Polymyxin Sulfate Ointment. DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 17/06/2015.

Buckingham R (ed). Polymyxin B Sulfate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 16/09/2015.

McEvoy GK, Snow EK, Miller J et al (eds). Polymyxin B Sulfate. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 16/06/2015.

Neomycin and Polymyxin B Sulfates and Hydrocortisone Solution. DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 17/06/2015.

Neomycin Sulfate, Polymyxin B sulfate and Gramicidin Solution/Drops. DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 17/06/2015.

Polymyxin B Sulfate Injection, Powder, for Solution. DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 17/06/2015.

Wickersham RM. Polymyxin B Sulfate. Facts and Comparisons [online]. St. Louis, MO. Wolters Kluwer Clinical Drug Information, Inc. https://www.wolterskluwercdi.com/facts-comparisons-online/. Accessed 17/06/2015.

Disclaimer: This information is independently developed by MIMS based on Polymyxin B from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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