Polymyxin B Sulfate is the Sulfate salt of Polymyxins B1 & B2, which are produced by the growth of Bacillus polymyxa. Polymyxin B Sulfate has a bactericidal action against almost all Gram negative bacilli. Polymyxins increase the permeability of the bacterial cell membrane leading to death of the cell.

Acute infections caused by susceptible strains of Pseudomonas aeruginosa:

Polymyxin B Sulfate is a drug of choice in the treatment of infections of the urinary tract, meninges, and bloodstream caused by susceptible strains of Pseudomonas aeruginosa.

It may be indicated in serious infections caused by susceptible strains of the following organisms, when less potentially toxic drugs are ineffective or contraindicated:

• H. influenzae: Specifically meningeal infections
• Escherichia coli: Specifically urinary tract infections
• Aerobacter aerogenes: Specifically bacteremia
• Klebsiella pneumoniae: Specifically bacteremia

Intravenous: Dissolve Polymyxin B 500,000 units in 300 to 500 ml solutions for parenteral Dextrose injection 5% for continuous drip.

Intramuscular: Dissolve Polymyxin B 500,000 units in 2 ml 0.9% Sodium Chloride solution. It is not recommended routinely because of severe pain at injection site, particularly in infants and children.

Intrathecal: Dissolve Polymyxin B 500,000 units in 10 ml 0.9% Sodium Chloride solution for 50,000 units per ml dosage unit.

In meningeal infections, Polymyxin B Sulfate should be administered only by the intrathecal route.

For IV route:

• Adult & Children (Normal kidney function): Dose (Units/kg/day) is 15,000-25,000(Not exceed 25,000) and Dosage frequency/Duration is infusions may be given every 12 hours over a period of approximately 60 to 90 minutes.
• Adult & Children (Renal impairment): Dose (Units/kg/day) is Less than 15,000 and Dosage frequency/Duration is Infusions may be given every 12 hours over a period of approximately 60 to 90 minutes.
• Infants (Normal kidney function): Dose (Units/kg/day) is Maximum 40,000

For IM route:

• Adult & Children: Dose (Units/kg/day) is 25,000-30,000 and Dosage frequency/Duration is Dose should be reduced in the presence of renal impairment. The dosage may be divided and given at either 4 or 6 hour intervals.
• Infants (Normal kidney function): Dose (Units/kg/day) is Maximum 40,000

For Intrathecal:

• Children under 2 years of age: Dosage frequency/Duration 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 cultures of the cerebrospinal fluid are negative and sugar content has returned to normal.
• Adults and children over 2 years of age: 50,000 units once daily 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.

Clostridium difficile associated diarrhea has been reported with use of Polymyxin B. Nephrotixic reactions: Albuminuria, cylinduria, azotemia, and rising blood levels, Neurotoxic reactions: Facial flushing, dizziness progressing to ataxia, drowsiness, peripheral aresthesias (circumoral and stocking glove), apnea due to concurrent use of curariform muscle relaxants, other neurotoxic drugs or inadvertent overdosage, and signs of meningeal irritation with intrathecal administration, e.g., fever, headache, stiff neck. Other reactions occasionally reported: Drug fever, urticaria rash, severe pain at IM injections sites and thrombophelbitis at IV injections sites.

Overdose Effects

Polymyxin-induced toxicity associated with overdose has been reported. Overdose of Polymyxin can result in neuromuscular blockade, which can lead to apnea, muscular weakness, vertigo, transient facial paresthesia, slurred speech, vasomotor instability, visual disturbance, confusion, psychosis and possible respiratory arrest. Overdose can also cause renal failure characterized by decreased urine output and increased serum concentrations of BUN and creatinine. There is no specific antidote for Polymyxin B Sulfate overdose. In case of Polymyxin B Sulfate overdose, the drug should be stopped and symptomatic treatment instituted. Quick diuresis by IV administered mannitol may help to enhance renal clearance of the drug and thus to reduce serum drug levels. Hemodialysis or peritoneal dialysis may help in order to manage renal complications.

Baseline renal function should be done prior to therapy, with frequent monitoring of renal function and blood levels of the drug during parenteral therapy.

Pregnancy & Lactation

There are no controlled data in human pregnancy. Safety has not been established during pregnancy. There is no recommendation regarding use during lactation. There is no study on whether it is secreted with human milk.