Polymyxin Generic

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*Based on the difference between the U&C price submitted and the price the patient paid, as of April 2023.

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  1. Medication
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  2. Polymyxin B Trimethoprim
    Generic for Polytrim
    10000 unit/mL 0.1%
    10mL solutions $7.03 USD
    Save $15.64
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Do you need a prescription for polymyxin?

Yes, polymyxin is only available with a valid physician Rx.

How much is polymyxin without Insurance in the US?

Our website gives two competitive savings options to US customers who wish to purchase polymyxin, as either a brand or generic, if available. The first is access to medications through our mail-order online pharmacy. The second is by using the Now Patient Rx Advantage Card, which can be used in over 65,000 pharmacies nationwide, across America. If you are insured, then in most cases, the cash price will be significantly cheaper than the copay.

What will my out-of-pocket cost be for polymyxin in the US?

There are no out-of-pocket (OOP) costs because we are currently only offering a cash-based option to purchase medications.

Is Now Patient a polymyxin savings card?

Yes. Save up to 90% on your polymyxin with the FREE Now Patient Rx Advantage card*.
*Based on the difference between the U&C submitted by the pharmacy and the price the patients pay.

Can you handle Rx transfers for home delivery in the US?

Yes. If you use the mail-order online pharmacy option, then we can handle requests by you to have your prescription transferred to our pharmacy for home delivery. We can even help you manage your refills by giving you timely reminders, so you do not run out of your medication.

Is Now Patient a polymyxin coupon provider in the US?

No. Now Patient does not provide polymyxin coupons or FREE polymyxin samples.

Do you accept commercial, Medicare or Medicaid coverage for polymyxin in the US?

No. Currently, we only offer cash-based options for purchase, therefore we do not require your insurance benefit details. In the future, our plan is to be able to handle commercial insurance, Medicare and Medicaid including cases where you have multiple health plans that provide benefit coverage (e.g. Medicaid and Commercial). We also anticipate being able to handle more complex scenarios such as using primary insurance combined with a manufacturer copay assistance program.

Does Now Patient work with Medicare?

Our cash-based prices for medications are typically cheaper than Medicare copays. We do not bill Medicare Part D (standalone drug coverage) or Medicare Advantage (combined health and drug coverage). When you purchase your medication from Now Patient, you will be doing so out of your pocket. The spend will not count towards your plan deductibles or gaps.

Does Now Patient work with Commercial Insurance?

Our cash-based prices for medications are typically cheaper than commercial plan copays. We do not bill your commercial plan. When you purchase your medication from Now Patient, you will be doing so out of your pocket. The spend will not count towards your plan deductibles or gaps.

What should you do if you use too much polymyxin?


Call your doctor right away or seek immediate medical attention if your symptoms do not improve or they become worse after using polymyxin. You can also call 800-222-1222 to reach the American Association of Poison Control Centers or use its online resource if you think you’ve used too much polymyxin. But if you have severe symptoms, call 911 (or your local emergency number) immediately or go to the nearest emergency room.


If you think it is an emergency, call 999 or find your nearest A&E
If you need help now, but it’s not an emergency go to 111.nhs.uk or call 111. Alternatively you can speak to one of our pharmacists or use the Now Patient app to make an appointment with your GP.

What should I do if I miss my dose?

There are occasions when people forget to take their medication at correct prescribed times. This may not only have an effect on potentially making the medication less effective but it may also inadvertently lead to taking doses too close together, thereby increasing the risks of side effects.

Click here to find out what to do if you forgot to take your medication

US brand name of polymyxin and manufacturer

Polymyxin is available in the US under various brand names, including colistimethate and polymyxin B. It is manufactured by multiple pharmaceutical companies.

UK brand name of polymyxin and manufacturer

Polymyxin is available in the UK under the brand name Colomycin. It is manufactured by Forest Laboratories UK Ltd.

Is polymyxin available in the UK on the NHS?

Yes, polymyxin (Colomycin) is available on the NHS in the UK. It can be prescribed by healthcare professionals for eligible patients.

Prescription requirement for polymyxin

Polymyxin is a prescription medication and requires a prescription from a healthcare provider.

FDA approval of polymyxin

Polymyxin has received FDA approval for the treatment of various infections caused by susceptible bacteria.

Active ingredient of polymyxin and mechanism of action

Polymyxin is an antibacterial belonging to a class of antibiotics called polymyxins. The active ingredient in polymyxin B is polymyxin B sulfate. Polymyxins B and E (colistin) are used for the treatment of multidrug-resistant gram-negative bacteria infections (pathogens).

They are part of a larger class of medications called nonribosomal peptides, and work by binding to lipopolysaccharides (LPS) and phospholipids in the bacterial cell membrane, increasing permeability by displacing divalent cations from phosphate groups of outer membrane lipids, leading to leakage of cellular contents and ultimately bacterial cell death. Structurally, colistin and polymyxin B differ by a single amino acid in the peptide ring.

Uses of polymyxin

Polymyxin is an antimicrobial polypeptide, primarily used for the treatment of bacterial infections caused by susceptible organisms, such as strains of multiple drug-resistant isolates, carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa (P. Aeruginosa), Klebsiella pneumoniae, Acinetobacter baumannii, gram-negative bacilli, Escherichia Coli (E. Coli) and most fungi and gram-positive bacteria. Clinical use of polymyxins is for the treatment of infectious diseases of the respiratory tract, urinary tract infections, and skin and soft tissue infections.

Forms of polymyxin

Polymyxin is available in various forms, including intravenous (IV) formulations, topical creams, and ointments. The specific form and strength will depend on the intended use and the formulation of the medication.

Dosage of polymyxin

The dosage regimen of polymyxin will vary depending on the specific infection being treated, the patient’s age and weight, and other factors. Loading doses should be considered for critically ill patients. It is important to follow the dosage instructions provided by your healthcare provider.

Precautions and warnings for polymyxin

  • Polymyxin may cause allergic reactions in some individuals. Inform your healthcare provider if you have a history of hypersensitivity to polymyxin or other antibiotics.
  • It may interact with certain medications, so it is important to inform your healthcare provider about all the medications you are taking, including prescription drugs, over-the-counter medications, and herbal supplements.
  • Polymyxin should be used with caution in patients with pre-existing problems with renal function or renal impairment or hearing impairment.
  • It is important to complete the full course of treatment prescribed by your healthcare provider, even if your symptoms improve
  • Although polymyxin antibiotics can be given parenterally, they do have an incidence of being neurotoxic and nephrotoxic, and are usually only used as a last resort if other, more modern antibiotics are not effective or are not recommended. They are mainly only used in topical or ophthalmic drugs, in combination with bacitracin and neomycin or tetracycline

Side effects of polymyxin

Polymyxin may cause side effects in some individuals. Common side effects may include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Allergic reactions
  • Kidney problems
  • Hearing problems

The most common adverse effect of intravenous polymyxins is nephro-toxicity. Contact your healthcare provider if you experience severe or persistent side effects.

Interactions with other drugs

Polymyxin may interact with certain medications, including neuromuscular blockers and other antibiotics. It is important to inform your healthcare provider about all the medications you are taking to avoid potential drug interactions.



Now Patient has taken all reasonable steps to ensure that all material is factually accurate, complete, and current. However, the knowledge and experience of a qualified healthcare professional should always be sought after instead of using the information in this page. Before taking any drug, you should always speak to your doctor or another qualified healthcare provider.

The information provided here about medications is subject to change and is not meant to include all uses, precautions, warnings, directions, drug interactions, allergic reactions, or negative effects. The absence of warnings or other information for a particular medication does not imply that the medication or medication combination is appropriate for all patients or for all possible purposes.

Stefano Mirabello Medical Reviewer
Pharmacist / B.Pharm
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