Polymyxin B: An explicit description

Polymyxin B is a group of essential polypeptide antibiotics derived from B polymyxa (B heterosporous). Polymyxin B (polymyxin b sulfate) sulfate is the sulfate salt of Polymyxins B1 and B2, which are produced by the growth of Bacillus polymyxa (Prazmowski) Migula (Fam. Bacillaceae). Healthcare professionals use this drug in treating patients with acute infections such as urinary tract infections, bloodstream infections, meningeal infections and corneal and subconjunctival eye infections.

Dosage and Administration

The Polymyxin B injection comes in 50000 IU to administer medicine intravenously, intramuscularly or intrathecally only to hospitalized patients under the constant supervision by the healthcare professionals. 

FOR INTRAVENOUS INFUSION

Dissolve Polymyxin B USP 500,000 iu in 300 to 500 mL solutions for parenteral dextrose injection 5% for continuous drip.

In the case of adults and children: The dosage of Polymyxin B is 15,000 to 25,000 units/kg body weight/day in individuals with normal kidney function. This amount should be reduced from 15,000 units/kg downward for individuals with kidney impairment. One should give an injection every 12 hours; however, the total daily dose must not exceed 25,000 units/kg/day.

In the case of infants: Infants with normal kidney function may receive up to 40,000 units/kg/day without adverse effects.

FOR INTRAMUSCULAR INFUSION

Not recommended routinely because of severe pain at injection sites, particularly in infants and children. Dissolve 500,000 polymyxin B units in 2 mL sterile water for injection, sodium chloride injection, or procaine hydrochloride injection 1%.

In the case of adults and children: The recommended dosage of Polymyxin B injection is 25,000 to 30,000 units/kg/day. One should reduce this dosage in the presence of renal impairment. The dosage may be divided and given at either 4 or 6-hour intervals.

In the case of infants: Infants with normal kidney function may receive up to 40,000 units/kg/day without adverse effects.

FOR INTRATHECAL INFUSION

Dissolve 500,000 polymyxin B (polymyxin b sulphate) units in 10 mL sodium chloride injection USP for 50,000 units per mL dosage unit.

In the case of adults and children above 2 years: 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: 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.

In case of eye infection: Dissolve 500,000 polymyxin B (polymyxin b sulfate) 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. To treat infections of the eye, administer a concentration of 0.1 per cent to 0.25 per cent, that is, 1 to 3 drops every hour, increasing the intervals as response indicates. 

Common Adverse Reactions

The common side effects of Polymyxin B are:

• Drug fever.
• Urticarial rash.
• Severe pain at intramuscular injection sites.
• Thrombophlebitis at intravenous injection sites.

If the side-effects get worse one should consult the healthcare professional immediately and the patient should be kept under observation.

Warnings and Precautions

• If a healthcare provider is prescribing Polymyxin B in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.
• Only experienced healthcare professionals should administer Polymyxin B injection inappropriate medical set up. 
• One should avoid using this medicine with other antibiotics as this drug may cause an overgrowth of nonsusceptible organisms, including fungi.
• One should never skip doses or leave the course of therapy in between as it may decrease the effectiveness of the immediate treatment. It may increase the likelihood of the bacteria that will develop resistance and will not be treatable by Polymyxin B or other antibacterial drugs in the future.
• Polymyxin-B Injection is nephrotoxic; therefore, one should evaluate the renal function before the course and regularly while on treatment.
•  The polymyxin B uses are restricted during pregnancy unless the expected benefit to the mother outweighs any potential risk to the fetus.

Price of Polymyxin B in India

In India, the Polymyxin B injection price is economical. There are several certified suppliers of generic medicines in India and worldwide. Ikris Pharma Network is one of the WHO-GDP certified suppliers of generic medicines, serving worldwide for more than 7 years.