| drug name | Polymyxin B |
| classification | Antibiotic (Aminoglycoside-like) |
| pharmacokinetics | | absorption | Poorly absorbed from the gastrointestinal tract. Primarily used topically or intravenously. | | distribution | Distributed throughout the body, although concentrations vary. Concentrations in the kidneys are notably high. | | metabolism | Minimal hepatic metabolism; primarily excreted by the kidneys. | | excretion | Renal excretion. Slow excretion in patients with impaired kidney function. |
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| suggested dosage | | note | Dosage is highly dependent on the route of administration and the specific infection. Consult a physician for appropriate dosage. | | IV | Initial dose varies but is typically around 2.5-5mg/kg IV q8h adjusted based on renal function | | Topical | Dosage based on the formulation and infected site. Consult package insert. |
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| indications | | 1 | Treatment of serious gram-negative bacterial infections, especially when other antibiotics are ineffective or contraindicated. | | 2 | Ocular infections (topical) | | 3 | Skin infections (topical) | | 4 | Severe systemic infections when aminoglycosides or other options are not suitable. |
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| safety in pregnancy | | category | C | | description | Polymyxin B should be used during pregnancy only if the potential benefits outweigh the potential risks. Limited data exists on its use in pregnant women, and its safety and potential for harm to the fetus is unclear. |
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| safety in breastfeeding | | description | Polymyxin B is secreted into breast milk. The potential risk to the infant is unclear. Use is not recommended during breastfeeding unless the benefit to the mother clearly outweighs the potential risk to the infant. | | recommendation | Consult a healthcare provider to weigh the benefits and risks |
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| side effects | | 1 | | category | Gastrointestinal | | description | Nausea, vomiting, diarrhea, abdominal pain |
| | 2 | | category | Renal | | description | Nephrotoxicity (kidney damage). This is a significant concern with polymyxin B; more frequent and severe in patients with impaired renal function or receiving high doses. |
| | 3 | | category | Neurological | | description | Peripheral neuropathy. Especially with long term use |
| | 4 | | category | Allergic | | description | Hypersensitivity reactions, including skin rash, itching, and anaphylaxis. |
| | 5 | | category | Other | | description | Local reactions at the injection site (IV or topical) |
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| alternatives | |
| contraindications | | 1 | Known hypersensitivity to polymyxin B | | 2 | Severe renal impairment |
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| interactions | | 1 | Caution should be exercised when using polymyxin B with other nephrotoxic drugs, as the risk of kidney damage is increased. | | 2 | Polymyxin B can interact with other medications that are renally cleared, potentially leading to increased drug levels and toxicity. |
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| warnings and precautions | | 1 | Close monitoring of renal function is crucial, especially in patients with pre-existing kidney problems or those receiving high doses. Regular blood tests to measure creatinine and BUN are essential. | | 2 | Patients should be monitored for signs of nephrotoxicity (e.g., decreased urine output, increased serum creatinine). | | 3 | Start with lower doses and titrate to effect, especially in patients with renal dysfunction, to minimize the risk of toxicity. |
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| additional information | | dosing adjustments | Dosage adjustments are crucial in patients with kidney disease. | | monitoring guidelines | Regular monitoring of kidney function and electrolytes is imperative to avoid complications. | | route specific details | Topical formulations may have different side effect profiles and contraindications than IV. |
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| patient specific details | | age | 25 years | | weight | 70 kg | | note | Age and weight are factors in determining appropriate dose, but specific dosage adjustment rules depend on renal function and the individual patient's response to therapy. A healthcare professional should determine the exact dose. |
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