This page contains brief details about the drug , it's indication, dosage & administaration, mechanism of action, related brands with strength, warnings and common side effects.

Background and Date of Approval

Polymyxin B is an antibiotic used in gram-negative infection treatment.

Mechanism of Action of undefined

Polymyxin B acts by disrupting the outer membrane of Gram-negative bacteria. It binds to and interacts with the lipopolysaccharide layer, a crucial bacterial cell wall component, causing membrane destabilization. This leads to increased permeability, leakage of cell contents, and eventual cell death. By targeting the outer membrane, this medication effectively neutralizes Gram-negative bacteria, making it particularly valuable in treating infections caused by these bacteria, especially in cases of multidrug resistance where other antibiotics may not be effective.

Uses of undefined

Polymyxin B treats severe bacterial infections, especially those caused by Gram-negative bacteria and multi-drug resistant strains. It is commonly used for infections like urinary tract infections, pneumonia, and ventilator-associated pneumonia caused by multidrug-resistant bacteria. This medication is available in intravenous and topical formulations, making it effective for systemic and localized bacterial infections.

undefined Drug administaration and Dosage available

Polymyxin B should be taken exactly as prescribed by a healthcare professional. It is available in various forms, such as tablets or capsules. The dosage and frequency depend on the medical condition being treated. This medication can be taken with or without food, and patients should not adjust the dosage or stop taking it without medical guidance. Following the doctor's instructions is very important, and if you experience any possible side effects, inform your healthcare provider immediately.

Warnings, Precautions and Side Effects of undefined


Polymyxin B can cause kidney and neurological problems, especially when used at higher doses or for prolonged periods. Severe allergic reactions, including anaphylaxis, can occur with this medication. It may cause gastrointestinal disturbances, including nausea, vomiting, and diarrhea. Discontinuation of this medication may lead to incomplete treatment and potential recurrence of the infection. Overuse or misuse of this medication can lead to bacterial resistance. 


Regular monitoring of kidney function and neurological status is essential during treatment. If any signs of allergic reactions such as difficulty breathing, swelling, or severe skin rash develop, seek immediate medical attention. Do not stop this medication abruptly without consulting your healthcare provider. Use Polymyxin B judiciously as directed by your healthcare provider to prevent the development of antibiotic-resistant bacteria.

Side Effects

Polymyxin B may cause various side effects, ranging from common to rare and potentially severe. Common side effects include pain, redness, or swelling at the injection site for intravenous administration, nausea, vomiting, diarrhea, loss of appetite, and skin irritation for topical application. More serious side effects are less common but require immediate medical attention if experienced. These include allergic reactions, indicated by difficulty breathing, severe skin rash, swelling of the face, lips, or tongue, and hives. This medicine can also cause kidney damage, with symptoms such as changes in urine output, swelling in the legs or feet, and fatigue. Neurotoxicity is another serious side effect, presenting as confusion, dizziness, difficulty walking, or muscle weakness.

Word Of Advice

When using Polymyxin B, taking certain precautions for safe and effective treatment is important. Inform your healthcare provider about known allergies, especially to antibiotics like colistin. Dose adjustments and close monitoring may be necessary for individuals with impaired kidney or liver function. Be vigilant for potential adverse effects, such as neurotoxicity, skin irritation, or allergic reactions, and promptly report any new or worsening symptoms. Avoid alcohol consumption while using this medication to prevent interactions and worsen side effects. Complete the full prescribed course of treatment, even if you start feeling better, to avoid bacterial resistance and superinfections. Follow your healthcare provider's advice on dosage and monitoring. To prevent potential drug interactions, keep all healthcare providers informed about your medication use. Store

Frequently Asked Question


  1. Goodman & Gilman’s, The Pharmacological Basis of Therapeutics, Protein synthesis inhibitors, and miscellaneous antibacterial agents, 12th edition, 2011, 1538 -1539.
  2. KD Tripathi, Essentials of Medical Pharmacology, Macrolide and other antibacterial antibiotics, 7th edition, 2013, 759.
  3. Bedford Laboratories, US Food, and Drug Administration, [Revised on June 2011] [ Accessed on 01st August  2023],


The drug information on this page is not a substitute for medical advice, it is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you can receive this treatment.