Polymax-B
Generic Name
Polymyxin B Sulfate
Manufacturer
Example Pharmaceuticals Ltd.
Country
Bangladesh
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Price Details
Current market pricing information
| Variant | Unit Price | Strip Price |
|---|---|---|
| polymax b 5 lac injection | ৳ 400.00 | N/A |
Description
Overview of the medicine
Polymyxin B is a potent polypeptide antibiotic primarily used to treat serious infections caused by susceptible Gram-negative bacteria, especially those resistant to other antibiotics. It is administered parenterally, commonly as an injection for severe systemic infections.
Uses & Indications
Dosage
Adults
Intravenous: 15,000 to 25,000 units/kg/day, divided into 2 doses, usually administered by slow infusion (over 60-90 minutes). Maximum 2.5 million units/day. Intrathecal: 50,000 units once daily for 3-4 days, then 50,000 units every other day for at least 2 weeks after CSF cultures are negative.
Elderly
Dosage adjustment based on renal function and body weight. Close monitoring for nephrotoxicity and neurotoxicity is crucial.
Renal_impairment
Significant dose reduction required. For CrCl <20 mL/min, dosage may need to be reduced to 7,500-12,500 units/kg every 2-3 days, with careful monitoring of serum polymyxin B levels and renal function. Not recommended in anuric patients.
How to Take
For intravenous (IV) administration, reconstitute the powder with 10 mL of sterile water for injection, then dilute in 300-500 mL of 5% Dextrose in Water (D5W) and infuse slowly over 60-90 minutes. Intrathecal administration requires specific sterile preparation and technique. Intramuscular administration is generally avoided due to severe pain and potential for neurotoxicity.
Mechanism of Action
Polymyxin B acts as a cationic detergent, disrupting the integrity of the bacterial outer and inner cell membranes of Gram-negative bacteria. This leads to increased permeability, leakage of intracellular components (e.g., ATP, nucleic acids), and ultimately bacterial cell death. It binds to the lipid A portion of lipopolysaccharides (LPS) in the outer membrane.
Pharmacokinetics
Onset
Rapid after intravenous administration (within minutes).
Excretion
Primarily excreted unchanged by the kidneys (approximately 60% within 24-48 hours). Elimination is significantly impaired in renal insufficiency.
Half life
Approximately 4.3 to 6 hours in patients with normal renal function, significantly prolonged in renal impairment.
Absorption
Poorly absorbed from the gastrointestinal tract and intact skin; well absorbed from intramuscular injection sites. Intravenous administration provides immediate systemic availability.
Metabolism
Minimal hepatic metabolism; primarily excreted unchanged.
Side Effects
Contraindications
- Hypersensitivity to polymyxin B or any component of the formulation.
- Concurrent use of other nephrotoxic or neurotoxic drugs when the risks outweigh the benefits.
- Patients with pre-existing severe renal impairment, unless absolutely necessary and under strict monitoring.
Drug Interactions
Cephalosporins (e.g., cefotaxime)
Possible synergistic effect against some Gram-negative bacteria, but also potential for additive nephrotoxicity.
Loop diuretics (e.g., furosemide)
May increase risk of ototoxicity and nephrotoxicity.
Aminoglycosides (e.g., gentamicin, amikacin)
Increased risk of nephrotoxicity and ototoxicity. Avoid concomitant use if possible.
Neuromuscular blocking agents (e.g., succinylcholine, rocuronium)
Enhanced and prolonged neuromuscular blockade, leading to increased risk of respiratory paralysis. Use with extreme caution.
Other nephrotoxic drugs (e.g., NSAIDs, amphotericin B, ciclosporin)
Additive nephrotoxicity; close monitoring of renal function is required.
Storage
Store intact vials at room temperature, below 25°C (77°F), protected from light. After reconstitution, the solution is stable for 72 hours when stored under refrigeration (2-8°C / 36-46°F).
Overdose
Symptoms of overdose include acute renal failure, neuromuscular blockade leading to respiratory paralysis, ataxia, dizziness, confusion, paresthesia, and slurred speech. Treatment is supportive; maintaining airway, ventilatory support if necessary, and hydration. Hemodialysis may be considered, but its effectiveness in removing polymyxin B is limited.
Pregnancy & Lactation
Pregnancy Category C. Polymyxin B should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is excreted into breast milk; therefore, caution should be exercised when administered to a nursing woman. The benefits of breastfeeding should be weighed against the potential risks to the infant.
Side Effects
Contraindications
- Hypersensitivity to polymyxin B or any component of the formulation.
- Concurrent use of other nephrotoxic or neurotoxic drugs when the risks outweigh the benefits.
- Patients with pre-existing severe renal impairment, unless absolutely necessary and under strict monitoring.
Drug Interactions
Cephalosporins (e.g., cefotaxime)
Possible synergistic effect against some Gram-negative bacteria, but also potential for additive nephrotoxicity.
Loop diuretics (e.g., furosemide)
May increase risk of ototoxicity and nephrotoxicity.
Aminoglycosides (e.g., gentamicin, amikacin)
Increased risk of nephrotoxicity and ototoxicity. Avoid concomitant use if possible.
Neuromuscular blocking agents (e.g., succinylcholine, rocuronium)
Enhanced and prolonged neuromuscular blockade, leading to increased risk of respiratory paralysis. Use with extreme caution.
Other nephrotoxic drugs (e.g., NSAIDs, amphotericin B, ciclosporin)
Additive nephrotoxicity; close monitoring of renal function is required.
Storage
Store intact vials at room temperature, below 25°C (77°F), protected from light. After reconstitution, the solution is stable for 72 hours when stored under refrigeration (2-8°C / 36-46°F).
Overdose
Symptoms of overdose include acute renal failure, neuromuscular blockade leading to respiratory paralysis, ataxia, dizziness, confusion, paresthesia, and slurred speech. Treatment is supportive; maintaining airway, ventilatory support if necessary, and hydration. Hemodialysis may be considered, but its effectiveness in removing polymyxin B is limited.
Pregnancy & Lactation
Pregnancy Category C. Polymyxin B should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is excreted into breast milk; therefore, caution should be exercised when administered to a nursing woman. The benefits of breastfeeding should be weighed against the potential risks to the infant.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
Typically 2-3 years when stored as per recommendations. Refer to the specific product label for precise shelf-life.
Availability
Hospitals, Pharmacies
Approval Status
Approved
Patent Status
Generic available
WHO Essential Medicine
YesClinical Trials
Polymyxin B has been in clinical use for decades. Its efficacy and safety, despite its toxicities, are well-established through extensive historical data and numerous clinical studies, particularly in the context of multi-drug resistant Gram-negative infections. Ongoing research focuses on optimizing dosing and combination therapies to mitigate toxicity.
Lab Monitoring
- Baseline and regular monitoring of renal function (serum creatinine, blood urea nitrogen (BUN), urine output, creatinine clearance) before and throughout therapy.
- Electrolyte levels (especially potassium, sodium, calcium) should be monitored.
- Serum polymyxin B levels (if available) for therapeutic drug monitoring and dose adjustment, particularly in patients with renal impairment.
- Neurological status should be assessed regularly.
Doctor Notes
- Polymyxin B is a last-resort antibiotic for serious MDR Gram-negative infections. Use only when clearly indicated and susceptible organisms are identified.
- Close monitoring of renal function, electrolytes, and neurological status is mandatory during therapy.
- Avoid concomitant use with other nephrotoxic or neurotoxic agents whenever possible.
- Administer via slow intravenous infusion (over 60-90 minutes) to minimize side effects. Intramuscular administration is strongly discouraged.
Patient Guidelines
- It is crucial to report any changes in urine output, swelling, confusion, dizziness, numbness, or muscle weakness immediately to your healthcare provider.
- Complete the entire course of treatment as prescribed, even if symptoms improve, to prevent recurrence and resistance.
- Inform your doctor about all other medications, including over-the-counter drugs, herbal supplements, and vitamins, to avoid potential drug interactions.
- This medication will be administered by a healthcare professional, usually in a hospital setting, due to its potential for serious side effects and the need for close monitoring.
Missed Dose Advice
If a dose is missed, administer it as soon as remembered. However, if it is almost time for the next scheduled dose, skip the missed dose and resume the regular dosing schedule. Do not double the dose to make up for a missed one.
Driving Precautions
Polymyxin B may cause dizziness, confusion, or blurred vision as part of its neurotoxic effects. Patients should be advised not to drive or operate heavy machinery if they experience these symptoms.
Lifestyle Advice
- Maintain adequate hydration by drinking plenty of fluids, especially during treatment, to support kidney function.
- Avoid alcohol consumption if experiencing dizziness or drowsiness, as it may exacerbate these side effects.
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