Polymyxin B Antibiotic: Uses, Dosage, and Side Effects Explained

Summary of Key Points

Polymyxin B is an antibiotic used to treat various bacterial infections, including those affecting the urinary tract, lungs (such as pneumonia), and skin. It works by either killing bacteria or preventing their growth. This medication is typically reserved for cases where other antibiotics have proven ineffective. Always consult your healthcare provider before starting or adjusting your dose. You can also schedule a telemedicine visit with one of our providers for personalized care.

Names of Medication

US Brand Name: Polymyxin B (generic name: Polymyxin B)

The generic name refers to the active ingredient, while the brand name is assigned by the manufacturer. In this case, Polymyxin B serves as both the brand and generic name.

Pharmacologic Category

Polymyxins

Other medications in this category include Colistin (Polymyxin E).

Polymyxin B Dosage

Polymyxin B is used to treat a variety of bacterial infections. The dosage and duration of treatment depend on the type and severity of the infection. Always consult your doctor before making any changes to your prescribed dose. If you need to speak with a healthcare provider, you can schedule a telemedicine visit with us.

1. Bacterial Infections: 15,000 to 25,000 units/kg/day, divided into 2 doses, for 7 to 14 days.
2. Urinary Tract Infections: 15,000 to 25,000 units/kg/day, divided into 2 doses, for 7 to 10 days.
3. Pneumonia: 15,000 to 25,000 units/kg/day, divided into 2 doses, for 10 to 14 days.
4. Meningitis: 50,000 to 100,000 units intrathecally (injected into the spinal canal) once daily for 3 to 5 days.
5. Sepsis: 15,000 to 25,000 units/kg/day, divided into 2 doses, for 7 to 14 days.
6. Skin Infections: Apply topically 1 to 3 times daily for 7 to 10 days.
7. Eye Infections: 1 to 2 drops of 10,000 units/mL solution every 4 hours for 7 to 10 days.
8. Ear Infections: 1 to 2 drops of 10,000 units/mL solution every 4 hours for 7 to 10 days.
9. Gastrointestinal Infections: 15,000 to 25,000 units/kg/day, divided into 2 doses, for 7 to 10 days.
10. Intra-abdominal Infections: 15,000 to 25,000 units/kg/day, divided into 2 doses, for 7 to 14 days.

Dosage Forms and Strengths

1. Injection: 500,000 units/vial (powder for reconstitution)
2. Topical ointment: 10,000 units/g
3. Ophthalmic solution (eye drops): 10,000 units/mL
4. Otic solution (ear drops): 10,000 units/mL

Administration Instructions for Polymyxin B

Polymyxin B is typically administered by a healthcare professional, especially when given as an injection. For topical, ophthalmic (eye), or otic (ear) use, follow your doctor’s instructions carefully. Be sure to wash your hands before applying the medication, and avoid touching the tip of the dropper or tube to any surface to prevent contamination. If you’re unsure how to use this medication, consult your healthcare provider or schedule a telemedicine visit with us for further guidance.

Polymyxin B Side Effects and Adverse Reactions

Common side effects: These may include mild irritation at the injection site, itching, or redness. These effects are usually temporary and tend to resolve on their own.

Serious side effects: These can include kidney damage, nerve damage, or muscle weakness. If you experience any of these symptoms, contact your doctor immediately.

Allergic reactions: In rare cases, some individuals may experience an allergic reaction, which can include rash, itching, swelling, or difficulty breathing. Seek emergency medical attention if you experience any of these symptoms.

Contraindications for Polymyxin B

A contraindication is a specific condition where a medication should not be used because it may cause harm. It’s important to know if you have any conditions that make taking Polymyxin B unsafe for you.

1. Known hypersensitivity to Polymyxin B: If you have a history of allergic reactions to Polymyxin B or other polymyxin antibiotics, you should not take this medication. Allergic reactions can range from mild skin rashes to severe anaphylaxis, which can be life-threatening.
2. Myasthenia gravis: Polymyxin B can worsen muscle weakness in people with myasthenia gravis, a condition that affects muscles and nerves. This is because Polymyxin B can interfere with nerve signals to muscles, leading to increased weakness.
3. Kidney disease: Polymyxin B is processed by the kidneys, and if you have impaired kidney function, the drug can accumulate in your system, leading to toxicity. This can cause further kidney damage or other serious side effects.

Polymyxin B Drug Interactions

Polymyxin B can interact with other medications, increasing the risk of side effects or reducing the effectiveness of either drug. Always inform your healthcare provider about all the medications you’re taking, including over-the-counter drugs and supplements.

1. Aminoglycosides (e.g., Gentamicin, Tobramycin): Combining Polymyxin B with aminoglycosides can increase the risk of kidney damage and hearing loss.
2. Neuromuscular blocking agents (e.g., Succinylcholine, Vecuronium): Polymyxin B may enhance the effects of these drugs, leading to prolonged muscle paralysis.
3. Loop diuretics (e.g., Furosemide, Lasix): Using Polymyxin B with loop diuretics can increase the risk of kidney damage and hearing loss.

Polymyxin B in Pregnancy

Is it safe to take Polymyxin B when pregnant?

Polymyxin B is classified as an FDA Pregnancy Category C drug. This means that while animal studies have shown potential risks to the fetus, there are no well-controlled studies in humans. In certain situations, such as life-threatening infections, the benefits of using Polymyxin B during pregnancy may outweigh the risks. It is crucial to discuss these risks and benefits with your healthcare provider before using Polymyxin B if you are pregnant. For personalized advice, you can also consult one of our telemedicine providers.

Polymyxin B While Breastfeeding

Is it safe to take Polymyxin B while breastfeeding?

There is limited information on whether Polymyxin B passes into breast milk. Due to the potential for serious side effects, including kidney damage and neurotoxicity, caution is advised when considering Polymyxin B while breastfeeding. It’s important to discuss the risks and benefits with your healthcare provider, who may suggest safer alternatives. If you have concerns, our telemedicine providers are available to help you make an informed decision.

Estimated Cost of Polymyxin B Medication

The estimated cost of a 30-day supply of Polymyxin B without insurance, using a GoodRX coupon, typically ranges from $50 to $100, depending on the pharmacy and location. Prices may vary, so it’s a good idea to check with your local pharmacy or use a prescription savings card to help reduce the cost.

Possible Alternatives to Polymyxin B

Depending on the type of infection, alternative treatments or lifestyle changes may be available. Always consult your healthcare provider before making any changes to your treatment plan. You can schedule a telemedicine appointment with one of our providers to explore these alternatives.

Alternatives for Bacterial Infections

Alternatives may include antibiotics such as amoxicillin or doxycycline, depending on the specific bacteria causing the infection. In some cases, probiotics and a healthy diet can support your immune system in fighting infections.

Alternatives for Urinary Tract Infections (UTIs)

Alternatives include antibiotics like nitrofurantoin or trimethoprim-sulfamethoxazole. Drinking plenty of water and cranberry juice may also help prevent UTIs.

Alternatives for Pneumonia

Depending on the cause, antibiotics such as azithromycin or levofloxacin may be considered. Vaccination and good hygiene practices can also help prevent future infections.

Alternatives for Meningitis

For bacterial meningitis, antibiotics like ceftriaxone or vancomycin may be used. Vaccination is essential for preventing certain types of meningitis.

Alternatives for Sepsis

Treatment for sepsis typically involves a combination of antibiotics and supportive care. Early intervention is critical, so consult a healthcare provider immediately if you suspect sepsis.

Alternatives for Skin Infections

Alternatives include topical antibiotics like mupirocin or oral antibiotics such as cephalexin. Keeping the skin clean and dry can help prevent infections.

Alternatives for Eye Infections

Antibiotic eye drops, such as tobramycin or erythromycin, may be alternatives. Practicing good eye hygiene and avoiding touching your eyes can help prevent infections.

Alternatives for Ear Infections

Alternatives include antibiotics like amoxicillin or ciprofloxacin ear drops. Keeping the ears dry and avoiding inserting objects into the ear canal can help prevent infections.

Alternatives for Gastrointestinal Infections

Depending on the cause, antibiotics such as metronidazole or ciprofloxacin may be alternatives. Staying hydrated and maintaining a balanced diet can support recovery.

Alternatives for Intra-Abdominal Infections

Alternatives include antibiotics like piperacillin-tazobactam or meropenem. Good hygiene and prompt treatment of gastrointestinal issues can help prevent these infections.

Recent Updates on Polymyxin B Research

Recent research on Polymyxin B has focused on its use in treating multidrug-resistant bacterial infections. Studies are exploring its effectiveness when combined with other antibiotics to combat resistant strains, such as carbapenem-resistant Enterobacteriaceae (CRE). Some findings suggest that Polymyxin B, when used in combination with other antibiotics, may improve outcomes in patients with severe infections caused by resistant bacteria. However, concerns about its potential toxicity, particularly to the kidneys and nervous system, remain a focus of ongoing studies. If you have concerns about antibiotic resistance or the use of Polymyxin B, our telemedicine providers can help you understand the latest research and how it may apply to your treatment plan.

James Kingsley

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