Parenteral Use: Nephrotoxicity; Neurotoxicity; Pregnancy Risk

• When this drug is given intramuscularly and/or intrathecally, it should be given only to hospitalized patients, so as to provide constant supervision by a physician.
• Renal function should be carefully determined and patients with renal damage and nitrogen retention should have reduced dosage. Patients with nephrotoxicity due to Polymixin B usually show albumunuria, cellular casts, and azotemia. Diminishing urine output and a rising BUN are indications for discontinuing therapy with this drug.
• Neurotoxic reactions may be manifested by irritability, weakness, drowsiness, ataxia, perioral paresthesia, numbness of the extremities, and blurring of vision. These are usually associated with high serum levels found in patients with impaired renal function and/or nephrotoxicity.
• The concurrent or sequential use of other neurotoxic and/or nephrotoxic drugs with polymixin B sulfate, particularly bacitracin, streptomycin, neomycin, kanamycin, genticamin, tobramycin, amikacin, cephaloridine, paromomycin, viomycin, and colistin, should be avoided.
• The neurotoxicity of polymixin B sulfate can result in respiratory paralysis from neuromuscular blockade especially when the drug is given soon after anesthesia and/or muscle relaxants.
• Usage in pregnancy: The safety of this drug in human pregnancy has not been established.