Polymyxin B

Frequency Not Defined

Anaphylactoid reactions with dyspnea and tachycardia

Eosinophilia

Fever

Nephrotoxicity

Neurotoxicity

Skin exanthemata

Urticaria

This is not a complete list of polymyxin Bdrug interactions. Ask your doctor or pharmacist for more information.

• It is used to treat bacterial infections.

• Polymyxin B Sulfate

Binds to phospholipids, alters permeability, and damages the bacterial cytoplasmic membrane permitting leakage of intracellular constituents

Absorption

Not absorbed from GI tract.

Distribution

Tissue diffusion is poor; critically ill patients: Central Vd: ~0.09 L/kg; peripheral Vd: 0.33 L/kg (Sandri 2013a); does not cross blood brain barrier into CSF or into the eye (Hoeprich 1970)

Excretion

Urine (<1% as unchanged drug within first 12 hours; as therapy continues, up to 60% as unchanged drug in the urine [Evans 1999]); Critically ill adults: Urine (median: 4% [range: 0.98% to 17.4%] as unchanged drug) (Sandri 2013a)

Time to Peak

Serum: IM: Within 2 hours (Hoeprich 1970)

Half-Life Elimination

6 hours, increased with reduced renal function (Evans 1999)

Protein Binding

~60% (Kassamali 2015); 79% to 92% (critically ill patients) (Zavascki, 2008)

Refer to adult dosing.

There are no dosage adjustments provided in the manufacturer’s labeling.

Frequency not defined.

Cardiovascular: Facial flushing

Central nervous system: Neurotoxicity (includes ataxia, blurred vision, drowsiness, irritability, numbness of extremities oral paresthesia), dizziness, drug fever, meningitis (intrathecal administration)

Dermatologic: Urticaria

Endocrine & metabolic: Hypocalcemia, hypochloremia, hypokalemia, hyponatremia

Genitourinary: Nephrotoxicity

Hypersensitivity: Anaphylactoid reaction

Local: Pain at injection site

Neuromuscular & skeletal: Neuromuscular blockade, weakness

When this drug is given IM, IV, 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 polymyxin B sulfate usually show albuminuria, cellular casts, and azotemia. Diminishing urine output and a rising blood urea nitrogen (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 or nephrotoxic drugs with polymyxin B sulfate, particularly bacitracin, streptomycin, neomycin, kanamycin, gentamicin, tobramycin, amikacin, cephaloridine, paromomycin, viomycin, and colistin should be avoided.

The neurotoxicity of polymyxin B sulfate can result in respiratory paralysis from neuromuscular blockade, especially when the drug is given soon after anesthesia or muscle relaxants.

The safety of this drug in human pregnancy has not been established.

Neurologic symptoms and signs of superinfection; renal function (decreasing urine output and increasing BUN may require discontinuance of therapy)