Polymyxin B sulfate is the sulfate salt of Polymyxins B1 and B2, produced by the growth of Bacillus polymyxa (Prazmowski) Migula (Fam. Bacillacea). It has a potency of not less than 6000 polymyxin B units per mg, calculated on an anhydrous basis. Polymyxin B injection is in powder form suitable for preparing sterile solutions for intramuscular, intravenous drip, intrathecal, or ophthalmic use. Polymyxin B for Injection is one of a group of basic polypeptide antibiotics derived from B polymyxa (B aerosporous). This drug is available in single-dose vials of 500000 IU.
Healthcare professionals use this drug in treating patients with Urinary tract infections, Bloodstream infections, Meningeal infections, and Corneal and subconjunctival eye infections.
The recommended dosage of Polymyxin B is as follows:
In case of intravenous infusion
One should dissolve 500,000 polymyxin B units in 300 to 500 mL solutions for parenteral dextrose injection at 5% for continuous drip.
In adults and children, the administration of Polymyxin B is 15,000 to 25,000 units/kg body weight/day in individuals with normal kidney function. One should reduce this amount from 15,000 units/kg for individuals with kidney impairment. Infusions may be given every 12 hours; however, the daily dose must not exceed 25,000 units/kg/day.
In infants, the administration of this drug is up to 40,000 units/kg/day without adverse effects only in infants with normal kidney function.
In the case of intramuscular infusion
Healthcare professionals don’t recommend administering Polymyxin B sulphate routinely because of severe pain at injection sites, particularly in infants and children. One should dissolve 500,000 Polymyxin B units in 2 mL sterile water for injection, sodium chloride injection, or procaine hydrochloride injection 1%.
In adults and children, the administration of this drug is 25,000 to 30,000 units/kg/day. One should reduce the amount in the presence of renal impairment. The dosage may be divided and given at either 4 or 6-hour intervals.
In infants, the administration of the drug is up to 40,000 units/kg/day without adverse effects in infants with normal kidney function.
In case of intrathecal infusion
This type of administration is the treatment of choice for Ps aeruginosa meningitis. One should dissolve 500,000 polymyxin B units in 10 mL sodium chloride injection USP for 50,000 units per mL dosage unit.
In the case of adults and children over 2 years of age, the recommended dosage is 50,000 units once daily intrathecally for 3 to 4 days, then 50,000 units once every other day for at least 2 weeks after cultures of the cerebrospinal fluid are negative and sugar content has returned to normal.
In the case of Children under 2 years of age, the recommended dosage is 20,000 units once daily, intrathecally for 3 to 4 days, or 25,000 units once every other day. Continue with a dose of 25,000 units once every other day for at least 2 weeks after cerebrospinal fluid cultures are negative and sugar content has returned to normal.
In the case of ophthalmic infusion
One should dissolve 500,000 polymyxin B units in 20 to 50 mL sterile water for injection or sodium chloride injection USP for 10,000 to 25,000 units per mL concentration.
For treating Ps aeruginosa infections of the eye, a concentration of 0.1 percent to 0.25 percent (10,000 units to 25,000 units per mL) is administered 1 to 3 drops every hour, increasing the intervals as response indicates.
Subconjunctival injection of up to 100,000 units/day may be used to treat Ps aeruginosa infections of the cornea and conjunctiva.
Note: All information mentioned in this article is provided just for informational, educational, and referential purposes only.