Polymyxin b

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 Ps. aeruginosa . It may also be used topically and subconjunctivally in the treatment of infections of the eye caused by susceptible strains of Ps. 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. …

• PARENTERAL: Intravenous Dissolve 500,000 polymyxin B units in 300 to 500 mL solutions for parenteral dextrose injection 5% for continuous drip
• Adults and children 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
• Infusions may be given every 12 hours; however, the total daily dose must not exceed 25,000 units/kg/day
• Infants
• Infants with normal kidney function may receive up to 40,000 units/kg/day without adverse effects
• Intramuscular 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 or sodium chloride injection or procaine hydrochloride injection 1%
• Adults and children 25,000 to 30,000 units/kg/day
• This should be reduced in the presence of renal impairment
• The dosage may be divided and given at either 4 or 6 hour intervals
• Infants
• Infants with normal kidney function may receive up to 40,000 units/kg/day without adverse effects
• Note: Doses as high as 45,000 units/kg/day have been used in limited clinical studies in treating prematures and newborn

• Patients should be counseled that antibacterial drugs including polymyxin B should only be used to treat bacterial infections
• They do not treat viral infections (e.g., the common cold)
• When polymyxin B is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed
• Skipping doses or not completing the full course of therapy may decrease the effectiveness of the immediate treatment and increase the likelihood that bacteria will develop resistance and will not be treatable by polymyxin B or other antibacterial drugs in the future. …

This drug is contraindicated in persons with a prior history of hypersensitivity reactions to polymyxins.

Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including Polymyxin B for Injection, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile . C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. …

See WARNING box. Nephrotoxic reactions: Albuminuria, cylinduria, azotemia, and rising blood levels without any increase in dosage. Renal system reactions: electrolyte and acid/base abnormalities (i.e., Pseudo-Bartter syndrome) Neurotoxic reactions: Facial flushing, dizziness progressing to ataxia, drowsiness, peripheral paresthesias (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 and increased cell count and protein cerebrospinal fluid. …

Take it when you remember, unless it is nearly time for the next dose. Then skip the missed one. Never take two doses at once to make up for it. Check your leaflet, as some medicines are different.