Colistineb

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Colistineb

Treatment option: Infection, Cystic Fibrosis

Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Colistineb

Colistineb is the medicinal product containing Colistimethate Sodium (CMS), a specialized, re-emerged antibiotic used to address severe infections caused by highly drug-resistant bacteria.

Property Description
Active ingredient Colistimethate Sodium (CMS)
Form Powder for solution
Pharmacological class Polymyxin antibiotic
General purpose Last-resort medicine against MDR bacteria
Origin Semi-synthetic (derived from Bacillus polymyxa)

Colistimethate Sodium: Defining a Last-Resort Antibiotic

CMS is classified as a prodrug belonging to the Polymyxin antibiotic class; it must be converted within the body into its potent, active form, Colistin. Its primary general purpose is to serve as a last-resort medicine when standard antibacterial treatments have failed to eradicate life-threatening systemic bacterial threats or persistent infections, particularly those caused by resilient Gram-negative bacteria. It is utilized in treating infections from multi-drug resistant organisms, specifically when other options are exhausted. The active agent's origin is semi-synthetic, as it is derived from the natural product Polymyxin E. This re-emergent drug profile makes it distinct from most modern agents.

What Are the Forms and Composition of Colistineb?

The physical form of the medicinal product is a sterile, single-ingredient powder for solution. This powder preparation requires the addition of an aqueous vehicle, such as sterile water for injection or saline solution, for reconstitution. As a single-ingredient product, its only active component is Colistimethate Sodium. Its preparation is strictly designed for two principal clinical routes of administration: parenteral delivery (typically via intravenous injection for systemic effects) or inhalation (via nebulization). The antibiotic is classified for use against infections where resistance to other antibiotics is suspected. This classification, which is recognized across multiple jurisdictions, confirms that the medicine is reserved for serious, complicated bacterial cases.

What side effects are possible with Colistineb?

Possible Side Effects and Safety Information

The safety profile of Colistineb is primarily characterized by the potential for major organ system toxicities, specifically affecting the kidneys and the nervous system.


Key Adverse Reactions and Safety Categories

System-Organ Class Involved Adverse Reactions Documented
Renal and Urinary Disorders Nephrotoxicity (kidney damage), which is generally dose-dependent and typically reversible upon discontinuing the drug. Less common reports include acute tubular necrosis and electrolyte and acid-base abnormalities (e.g., hypokalemia, metabolic alkalosis).
Nervous System Disorders Neurotoxicity is common, presenting as transient neurological disturbances such as numbness, tingling (paresthesia) of the mouth, face, or extremities, vertigo, dizziness, and slurred speech. More severe effects like mental confusion, seizures, and psychosis have been reported, particularly with high doses or in patients with impaired renal function.
Respiratory Disorders Apnea and respiratory arrest have been reported, primarily associated with high serum concentrations, especially in the context of impaired kidney function or drug interactions. Bronchoconstriction has been reported with inhaled use.
Gastrointestinal Disorders Clostridium difficile-associated diarrhea (CDAD) is documented, ranging from mild diarrhea to fatal colitis.

Safety-Related Restrictions and Considerations

Impaired Renal Function

Patients with pre-existing kidney dysfunction are at a significantly increased risk for developing severe adverse effects, including apnea and neuromuscular blockade. Official documents require caution and dose adjustment based on the extent of renal impairment.

Concomitant Use and Drug Interactions

The drug is contraindicated in individuals with a history of hypersensitivity. There is a specific restriction against the simultaneous use of Colistineb with curariform muscle relaxants due to the heightened risk of respiratory arrest. Extreme caution is also advised when the drug is used with other medications known to be nephrotoxic (damaging to the kidneys) or neurotoxic (damaging to the nerves/brain) due to the potential for potentiated toxicity.

Overdose and Emergency Response

Overdose and when to seek help — Official Regulatory Information for Colistineb

This section describes the documented clinical signs of Colistimethate Sodium overdose and the immediate actions mandated by regulatory authorities.


Overdose Scope

Feature Regulatory Documentation Status
Documented overdose presentations: Paresthesia (tingling/numbness, often facial), vertigo, dizziness, slurred speech, visual disturbances, and muscle weakness.
Physiological systems affected: Neurological system (neurotoxicity) and Renal system (nephrotoxicity).
Dose-related or exposure-related factors: High serum concentrations associated with overdosage or failure to reduce the dose in patients with impaired renal function can lead to increased risk of toxicity.
Population-specific overdose notes: Impaired renal function significantly increases the possibility of apnea (respiratory arrest) and neuromuscular blockade following administration.
Emergency-response statements: Seek immediate medical attention for any suspected overdose.
When immediate medical help is required: Upon the onset of severe neurological symptoms, pronounced muscle weakness, or difficulty breathing (apnea).

Overdose Classifications (High-Level)

Classification Feature Regulatory Status
Severity classification: Overdosage can result in severe, life-threatening outcomes, including acute renal failure and respiratory failure.
Overdose-context constraints: Management is supportive and symptomatic; no specific antidote is known.

Resulting Overdose Structure

Official overdose statements:

  • Overdose may present as neurotoxic events like paresthesia and vertigo, or the severe outcome of apnea.
  • Acute renal failure (renal insufficiency) is a documented consequence of overdosage.
  • Immediate medical attention is required for suspected overdose to manage the potential for neuromuscular blockade.

Connection to the overall overdose profile: Regulatory documents define the Colistineb overdose profile based on documented systemic toxicity, primarily involving the neurological and renal systems. The core risk is progression to life-threatening respiratory failure or acute renal impairment, a risk heightened in patients with reduced kidney function. Due to the officially documented absence of a specific antidote, the mandated response centers on immediate emergency care and supportive treatment.

Therapeutic Uses of Colistineb

What Colistineb Treats: Main Uses and Benefits

The primary therapeutic role of Colistineb (Colistimethate Sodium) is to manage severe infections and is applied in clinical settings that involve acute or unstable symptom patterns due to highly resistant bacteria. Colistineb is considered relevant for the treatment of serious infections due to susceptible bacteria, particularly in situations where therapeutic alternatives are limited or when standard treatment options are exhausted.

The medication is commonly used across conditions presenting with acute episodes like sepsis, bacteremia, and complex forms of hospital-acquired pneumonia, and is relevant for the long-term management of chronic infections such as those seen in Cystic Fibrosis and Bronchiectasis. It plays a supportive role in addressing pathogens that have developed high resistance, including Multidrug-Resistant (MDR) and Carbapenem-resistant strains. The medicine helps address symptom clusters that may become intense or disruptive, such as high fever, signs of systemic stress, and frequent, purulent sputum. This use contributes to easing the overall symptom load when therapeutic alternatives are limited and supports general well-being during symptomatic phases.

“Colistineb is applied across domains where additional symptomatic support is needed against challenging, highly resistant bacterial infections.”

Quick Fact: Supportive Relief for MDR Infections
Common Scenario: Applied in clinical settings that involve acute or unstable symptom patterns caused by highly resistant bacteria.
Benefit Focus: Provides supportive relief when symptoms interfere with daily functioning.

Eligibility and Restrictions for Use

Who Can and Cannot Use Colistineb?

The official eligibility profile for Colistineb defines populations who must not use the medicine and those who require special medical consideration before use. This information is based on formal regulatory documents.


Formal Contraindications (Must Not Use)

Use of Colistineb is formally contraindicated in patients with a confirmed history of hypersensitivity (allergy) to colistimethate sodium, colistin base, or any other component of the formulation. Additionally, patients diagnosed with myasthenia gravis may be contraindicated or require extreme caution due to the risk of neuromuscular blockade.


Populations Requiring Special Consideration

Population/Condition Eligibility Status & Constraint
Impaired Renal Function Requires mandatory dosage reduction and use with the greatest caution to mitigate the risk of toxicity.
Pregnancy Not recommended or used only if the potential benefit justifies the potential risk to the fetus, as the drug crosses the placenta. Women of childbearing potential should use effective contraception.
Lactation Use only if the benefit to the mother outweighs the potential risk to the nursing infant, as excretion into breast milk is not fully established.
Infants (< 1 year) Used with caution; dosage must account for immature renal function.

Eligibility for treatment is also restricted to situations where the infection is confirmed or strongly suspected to be caused by susceptible bacteria and when other effective antibiotic options are unavailable or inappropriate.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Colistineb (Colistimethate Sodium) has officially documented interaction patterns focused on pharmacodynamic synergism and pharmacokinetic interference. Co-administration is formally advised against or requires extreme caution with medicinal products known to cause nephrotoxicity, such as Sodium Cephalothin and Aminoglycoside antibiotics, as this increases the documented risk of kidney damage. The medicine also requires the avoidance of co-administration with curariform muscle relaxants due to the potential for potentiating neuromuscular blockade, which increases the risk of serious respiratory complications.

For the inhalation route, a mandatory timing rule applies: nebulised Colistineb must not be administered within one hour of nebulised Dornase Alfa.

Regarding systemic exposure, regulatory documents confirm that Colistineb does not induce major CYP450 enzymes. However, the medicine may decrease the excretion rate of other renally cleared drugs, such as Abacavir or Acetaminophen, potentially leading to higher systemic exposure of the co-administered agent. Population-specific notes indicate that the risk of neuromuscular blockade is officially increased in patients with impaired renal function or conditions like Myasthenia Gravis. Regulatory labels confirm no known interactions with food or drinks are documented.

Mechanism of Action

How Colistineb Works

Colistineb, containing the prodrug Colistimethate Sodium, must first undergo hydrolysis in vivo to yield its active component, Colistin. This mechanism is primarily a physicochemical attack on the structural integrity of Gram-negative bacteria, leading to the bactericidal effect.


Prodrug Activation and Target Membrane Disruption

Colistin is highly cationic and initiates its action by targeting the anionic Lipid A component of the bacterial outer membrane. It binds electrostatically to Lipid A, actively displacing the stabilizing divalent cations ( Ca^2+ and Mg^2+). This destabilization allows the molecule to penetrate the outer layer and insert itself into the cytoplasmic (inner) membrane.


Homeostatic Collapse and Endotoxin Neutralization

Acting as a cationic detergent in the inner membrane, Colistin rapidly increases permeability, resulting in the uncontrolled efflux of essential intracellular contents (e.g., nucleic acids, ions). This irreversible structural collapse results in cell lysis. Additionally, Colistin directly binds and neutralizes circulating Endotoxin (Lipid A) that is released during the cell destruction process, limiting the Endotoxin's ability to engage immune pathways.


Constraint by Target Modification

The mechanism faces constraints when bacteria enzymatically modify the Lipid A structure, such as through the addition of L-Ara4N or pEtN. These modifications reduce the negative charge on the target, which impairs the essential electrostatic binding of Colistin and limits its action against those specific microbial populations.

Dosage and Administration Information

How Colistineb is Used: Official Administration Guidelines

Colistineb, which contains Colistimethate Sodium (CMS), is an antibiotic administered exclusively through routes that require specific preparation and procedural control. The medication is supplied as a sterile powder for solution that must be reconstituted and diluted prior to use.


Official Routes and Dosing Units

The primary route for systemic treatment of serious infections is Intravenous (IV) Infusion. For pulmonary infections, administration is via inhalation using a nebulizer. The official labeling uses two different metrics for dosage: International Units (IU) (standardized in the European context) or milligrams of Colistin Base Activity (mg CBA) (standardized in the US context).


Systemic Dosing and Schedule

For adults with normal renal function, the systemic daily dose ranges from 2.5 to 5.0 mg/kg of CBA (US) or approximately 9 Million IU (MIU) (EU). The total daily dose is divided and administered in 2 to 4 separate doses. Administration must follow a precise time-based protocol, requiring the final solution to be infused slowly over a period of 30 to 60 minutes.

Administration Requirements

Dosage is critically dependent on renal function; official instructions mandate dose reduction or adjustment of the frequency interval in the presence of measured renal impairment. For pediatric patients, the systemic dose is typically 75,000 to 150,000 IU/kg per day, divided into three separate administrations. The entire process—from reconstitution to final infusion—is generally conducted within a hospital setting under supervision due to the required complexity of preparation and the nature of the drug's use.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Colistineb


Evidence for Serious Systemic Infections (Intravenous Use)

Research examined the use of Colistineb in patients with conditions associated with acute or disruptive episodes, such as sepsis or certain forms of hospital-acquired pneumonia (HAP). This medicine was evaluated in patients whose infections were caused by multi-drug resistant (MDR) Gram-Negative bacteria, where treatment alternatives were few.

The research exploring this use includes short-term randomized controlled trials (RCTs), where Colistineb was observed in comparison to other antibiotics. These studies monitored short-term outcomes related to physical discomfort and physiological strain, such as 14-day and 28-day mortality rates and outcomes related to a change in clinical status.

Findings were mixed, and data show patterns related to inconsistencies across these studies. Research highlights changes measured during the study period, but evidence remains limited in the number of large, definitive RCTs.


Evidence for Chronic Pulmonary Infections in Cystic Fibrosis (Inhaled Use)

Colistineb was evaluated in research contexts involving chronic lung infection caused by the bacteria Pseudomonas aeruginosa in people with Cystic Fibrosis (CF). The evidence was evaluated in well-designed, long-term randomized controlled trials that observed responses over defined time intervals.

The outcomes research examined were long-term factors that reflect daily functioning or activity level, such as the annualized frequency of pulmonary exacerbations and changes in lung function (measured by FEV1). Studies explored how the medicine was associated with the microbiological status of the airways.


Evidence for Chronic Pulmonary Infections in Non-Cystic Fibrosis Bronchiectasis (Inhaled Use)

This medicine was evaluated in long-term clinical trials for adults diagnosed with Non-Cystic Fibrosis Bronchiectasis (NCFB) who have chronic P. aeruginosa infection. These trials were often randomized and placebo-controlled, and studies explored outcomes related to episodic or acute changes.

The primary outcome research examined was the annualized rate of pulmonary exacerbations observed over a 12-month period. Data show patterns related to the frequency of exacerbations; however, one of the two major trials was prematurely terminated. This evidence quality varies across studies and led to mixed findings regarding the primary outcome in the two large, identical trials that were conducted.


What Research Gaps and Uncertainties Remain

Scientific reviews and regulatory reports indicate that certainty remains low in several key areas of research for Colistineb. The reliance on retrospective studies for systemic indications means evidence quality varies across studies. A significant gap is the difficulty in reliably predicting the exact concentration of the drug within the body, especially in critically ill patients. This research does not determine whether an individual will respond similarly and highlights why further research is ongoing.

Frequently Asked Questions (FAQ)

Common questions about Colistineb (FAQ)


Q: Does Colistineb work against infections caused by viruses like the common cold?

A: Colistineb is a polymyxin antibiotic that is officially indicated to treat serious bacterial infections. According to official product information, this medicine is not used to treat infections caused by viruses, such as the common cold or the flu.


Q: What are the signs of potential nerve problems from Colistineb?

A: Official drug labels list neurotoxicity as a possible adverse reaction. Transient neurological disturbances have been reported, which may include symptoms like numbness or tingling (paresthesia) around the mouth, face, or extremities, as well as dizziness or slurred speech.


Q: Is having a rash a common reaction to Colistineb?

A: Rashes are noted in official regulatory documents as a possible adverse reaction. Other reported skin-related symptoms may include generalized itching, which is known as pruritus.


Q: Are there any late-onset side effects after stopping Colistineb?

A: Official regulatory documents indicate that monitoring of kidney function may continue for a period after treatment ends. Increases in serum creatinine, a sign of potential kidney effects, have been known to continue for 1 to 2 weeks following the discontinuation of the medicine.


Q: Does the injection hurt when it is given?

A: For the intravenous route, adverse reactions reported in official documents include swelling, tenderness, or pain at the injection site.


Q: Can Colistineb be taken as a pill or by mouth?

A: The product containing Colistimethate Sodium is supplied as a sterile powder for solution intended for intravenous infusion or inhalation. The medicine is not officially formulated as a pill or oral dosage form for systemic use.


Q: Can Colistineb interact with other commonly used antibiotics?

A: Regulatory documents state that using Colistineb concurrently with other medicines known to be damaging to the kidneys (nephrotoxic), such as certain aminoglycoside antibiotics, is officially advised against or requires caution due to the documented risk of increased toxicity.


Q: Are there any vitamins or supplements that should be avoided with Colistineb?

A: Official safety guidelines generally recommend informing a healthcare professional about all medicines, vitamins, and supplements being used, as potential interactions need to be assessed.


Q: Can drinking alcohol while on Colistineb cause problems?

A: While the regulatory documents primarily focus on drug-to-drug interactions, general safety guidance notes that alcohol can sometimes interact with medicines. The risk of dizziness, which is a known side effect of the medicine, may be increased when consumed with alcohol.


Q: Can older adults or geriatric patients use Colistineb safely?

A: Official studies have not identified specific problems in the elderly that would limit the drug's use. However, older patients are more likely to have age-related reduced organ function, and the medicine's official instructions specify that caution and dosage adjustment may be necessary in the presence of reduced organ function.


Q: What medical conditions make a patient ineligible for Colistineb?

A: Colistineb is formally contraindicated (must not be used) in patients with a confirmed allergy (hypersensitivity) to colistimethate sodium, colistin base, or any other component of the formulation. Patients with myasthenia gravis also require special caution due to the documented risk of neuromuscular blockade.


Q: Why is Colistineb sometimes considered a less effective option than Polymyxin B?

A: Official reviews and guidelines note that Colistineb is a pro-drug that requires conversion in the body to its active form, Colistin. This conversion is often slower and more variable compared to Polymyxin B, which is administered in its already active form. This difference in activation is cited as the basis for comparison.


Q: Is Colistineb associated with C. difficile infection?

A: Yes, Clostridium difficile is a bacterium that can cause severe intestinal inflammation and diarrhea. According to official product information, C. difficile-associated diarrhea (CDAD) is documented as a possible adverse reaction, ranging from mild diarrhea to fatal colitis.


Q: Is Colistineb used to treat infections that affect the brain or spinal cord (meningitis)?

A: Clinical literature reviewed by regulatory bodies notes that the medicine has been administered directly into the spinal canal (known as intrathecal or intraventricular administration) for specific infections affecting the central nervous system, such as meningitis, when other treatments have been exhausted.


Q: Is Colistineb a type of penicillin?

A: No. Official regulatory documents classify Colistineb as belonging to the polymyxin class of antibiotics. It is structurally and functionally distinct from the penicillin class of medicines.


Q: What class of antibiotics does Colistineb belong to?

A: Colistineb belongs to the polymyxin class of antibiotics.


Q: Does Colistineb cause problems with liver function?

A: The official safety profile of Colistineb primarily highlights adverse effects on the kidneys (nephrotoxicity) and the nervous system (neurotoxicity). Significant liver function problems are not typically highlighted among the primary severe adverse reactions in regulatory documents.


Q: What is the main reason Colistineb was not used widely for many years?

A: Scientific and historical context reviewed by regulatory agencies notes that the drug’s widespread use decreased significantly after newer antibiotics with fewer side effects became available. Its re-emergence today is due to the growing global rise of multi-drug resistant bacteria.


Q: Is it common for patients to receive Colistineb at home?

A: The intravenous form is typically administered in a hospital or clinical setting due to its complexity and the nature of the serious infections it treats. However, the inhaled form is commonly used by patients at home for chronic pulmonary infections after specialized instruction from a healthcare provider.


Q: What are the general safety guidelines for storing unmixed Colistineb vials?

A: General safety guidelines advise that the vials should be stored in the outer carton to protect the powder from light. They must not be stored above 25 C and the medicine is required to be kept out of the sight and reach of children.


Q: Why are there concerns about using Colistineb in patients who also have lung conditions like asthma?

A: Official documents note that when given via inhalation, Colistineb may induce coughing or bronchospasm (narrowing of the airways). Official documents contain a specific warning regarding use in patients with pre-existing lung conditions, such as asthma, due to this risk.


Q: How many different ways can Colistineb be administered (e.g., IV, inhaled)?

A: The official product information lists two principal routes for administering the drug: Intravenous (IV) Infusion for systemic treatment and inhalation via nebulization for pulmonary infections.


Q: What is the difference between Colistineb that is injected and the version that is inhaled?

A: The two routes serve different purposes: IV injection is used for systemic treatment to reach serious infections throughout the body, while inhalation is typically used to target the medicine directly to the lungs for treating chronic pulmonary infections.


Q: Why is the inhaled form of Colistineb sometimes used for cystic fibrosis patients?

A: Research and official documents confirm the medicine has been evaluated for chronic lung infections caused by bacteria like Pseudomonas aeruginosa in people with Cystic Fibrosis (CF). The inhaled route is used to target the medicine to the lungs, which is the primary site of chronic infection in CF.


Q: Why are the different dosing systems (IU vs. mg) for Colistineb confusing?

A: Official product labeling uses two different metrics for dosage: International Units (IU) is standardized in the European context, while milligrams of Colistin Base Activity (mg CBA) is used in the US context. The difference in these standardized measurements is the source of the dosing system variation.


Q: How long does it typically take for Colistineb to show signs of working?

A: While the Research Evidence section discusses long-term outcomes of clinical studies, such as the change in lung function over time, the official documentation does not provide a general timeline for the onset of effect or when an individual patient can expect to see improvement.


Q: What is the stability of the reconstituted solution?

A: The powder preparation is required to be mixed under strict, clean conditions. The resulting solution is generally intended for immediate use due to the risk of microbial contamination. If necessary, chemical and physical stability are demonstrated for a maximum of 24 hours when stored refrigerated.

How should Colistineb be stored and disposed of?

Storage Conditions

Item Official Requirement
Powder Storage Do not store the vials above 25 C [Source 1.1, 2.5].
Protection Keep the vials in the outer carton to protect the powder from light [Source 2.5].
Child Safety The product must be stored locked up (P405), and kept out of the sight and reach of children [Source 3.4, 4.4].

Stability of Reconstituted Solution

The powder must be mixed with the required liquid (reconstituted) under strict aseptic conditions. The reconstituted solution (at concentration ge 80,000 IU/mL) should be used immediately due to the risk of microbial contamination [Source 2.5]. If necessary, the chemical and physical stability is demonstrated for 24 hours when stored refrigerated (2 to 8 C) [Source 2.5]. Solutions that are diluted further for infusion must be used immediately [Source 2.5].

Disposal Requirements

Unused or expired Colistineb and its containers must not be thrown away with household garbage or allowed to reach the sewage system [Source 3.4]. Disposal must strictly comply with local, regional, and national regulations for pharmaceutical waste handling [Source 3.4].

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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