Klion

Quick links to important sections

Medically reviewed

Marina Burgos

Last updated on 10/01/2026

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 Klion

Klion: Identity, Classification, and Composition

Property Description
Active ingredient Metronidazole
Forms Tablet, Solution for infusion, Vaginal suppository
Pharmacological class Anti-infective agent, Nitroimidazole derivative
Target Pathogens Anaerobic bacteria and Protozoal parasites
Origin Synthetic drug

Identity and Classification

Klion is a trade name for preparations containing the active compound Metronidazole, which is formally classified as a synthetic nitroimidazole derivative within the broader category of anti-infective agents. This compound is a synthetic drug, and its primary pharmacological role is defined as an antiprotozoal drug and an antibacterial drug targeting specific types of pathogens. Metronidazole is recognized globally as an essential medicine for its foundational role in treating infections, as it is considered one of the effective and safe medicines needed in a health system. Klion is manufactured as a single active ingredient product in multiple forms, including tablets for oral use, solutions for infusion for intravenous delivery, and vaginal suppositories for local application, allowing for both Systemic administration and Local administration.


General Purpose and Mechanism

Klion (Metronidazole) is clinically recognized for its efficacy against specific microbial threats. The general purpose of the drug is to eliminate and neutralize specific pathogens, primarily anaerobic bacteria and certain protozoal parasites, that cause various infections in the body. The drug achieves this by exhibiting a unique selective toxicity: the Metronidazole component is activated only within the low-oxygen environments created by these pathogens. Once activated, it releases highly reactive products that cause irreversible damage to the microbes’ DNA and other vital structures. This specific mechanism of targeted cellular disruption makes Klion a primary option for controlling and eradicating infections caused by these susceptible organisms.

What side effects are possible with Klion ?

Possible Side Effects and Safety Information

The safety profile of Klion (Metronidazole) is officially categorized by frequency and the body system affected, based on regulatory documentation from authorities such as the EMA and FDA. This classification helps define the risk profile of the medicine.


Frequency-Classified Adverse Reactions

The most frequently reported reactions are classified as Very Common (ge 1/10) and include a metallic taste and nausea. Effects officially classified as Common (ge 1/100 to < 1/10) include headache and abdominal cramps.

Rare, but documented, reactions classified as Rare (ge 1/10,000 to < 1/1,000) include cholestatic hepatitis and blood changes such as agranulocytosis.


System-Organ Class and Serious Adverse Events

The official labeling groups adverse reactions primarily under Gastrointestinal Disorders and Nervous System Disorders. Serious adverse events, although rare, are formally documented, including Encephalopathy, Aseptic Meningitis, and persistent Peripheral Neuropathy. Severe reactions affecting the skin, known as SCARs (e.g., Stevens-Johnson syndrome), are also noted in official regulatory texts.


Regulatory Safety Constraints

The risk of Peripheral Neuropathy is officially associated with prolonged treatment or high cumulative doses, a key duration-related safety pattern. A critical safety constraint is the mandatory restriction on alcohol consumption during and shortly after treatment, due to the documented risk of a severe disulfiram-like reaction. Official labels also note that caution is required in patients with severe hepatic impairment due to the potential for drug accumulation.

Overdose and Emergency Response

Overdose and when to seek help

The official regulatory profile for Klion (Metronidazole) overdose is defined by the manifestation of severe neurological and gastrointestinal effects, which are documented outcomes of massive, high-dose exposure.

The Documented Manifestations of overdose include neurological symptoms such as ataxia (a lack of muscle coordination), disorientation, and severe gastrointestinal disturbances like nausea and vomiting. More severe outcomes officially documented in regulatory information include the occurrence of seizures (convulsions) and the potential development of irreversible peripheral neuropathy.

For any suspected overdose, the official guidance mandates that individuals must seek immediate medical attention or emergency medical care and contact a poison control center immediately.

The official Supportive Management approach states that no specific antidote is known for Metronidazole overdose. Therefore, clinical management must be strictly symptomatic and supportive treatment. Hemodialysis is documented as a procedure that can be beneficial for removing the drug and its metabolites from the body, and close professional observation, including the monitoring of central nervous system function, is required.

Therapeutic Uses of Klion

Klion is a prescription medication used for the management of conditions caused by anaerobic bacteria and certain parasites. Its intended use is to help ease symptoms associated with various susceptible infections.

Klion is indicated for conditions such as amebiasis (acute intestinal amebiasis and amebic liver abscess), trichomoniasis (symptomatic and asymptomatic infections in females and males), and serious infections caused by susceptible anaerobic bacteria. Examples of these serious infections may include infections of the blood (septicemia), central nervous system (meningitis), lower respiratory tract (pneumonia), and bone/joint tissue.

“This medicine is a recognized component in the management of specific bacterial and parasitic infections.”

The overall therapeutic aim is to help ease infection symptoms and address the underlying condition.


Quick Fact: Relief for Infection Symptoms

Eligibility and Restrictions for Use

Klion (Metronidazole) eligibility is defined by official regulatory documentation concerning pre-existing conditions, concomitant medications, and physiological status. Absolute prohibitions against use are mandated for certain patient groups, while other populations require careful monitoring.

Contraindicated Populations (Must Not Use)

Classification Eligibility Exclusion
Absolute Prohibition Patients with a prior history of hypersensitivity to metronidazole or other nitroimidazole derivatives.
Drug/Substance Exclusion Patients who have taken Disulfiram within the last two weeks or who are consuming alcohol (including propylene glycol) during or for three days after therapy.
Genetic Risk Patients with Cockayne syndrome, due to the risk of severe hepatotoxicity.

Restricted and Conditional Use

Eligibility is limited or conditional for the following:

  • Severe Organ Dysfunction: Patients with severe hepatic impairment (Child-Pugh C) are restricted and require a formal reduction of the usual dose. Patients with end-stage renal disease require close monitoring for metabolite accumulation.
  • Age-Related Limitations: Use in the pediatric population is not established for all indications, though it is documented for amebiasis. Newborn infants require caution due to diminished drug elimination capacity.
  • Reproductive Status: The drug is contraindicated in the first trimester of pregnancy when treating trichomoniasis. For breastfeeding mothers, use is conditional, and a temporary interruption of nursing may be required.

What should I know about interactions with other medicines?

Klion Interactions with other medicines and products

Official regulatory information requires strict awareness of co-administration risks, classifying interactions based on potential severity and resulting restrictions.

Contraindicated Combinations and Mandatory Avoidance

  • Alcohol (Ethanol) and Propylene Glycol: Consumption of alcoholic beverages or products containing propylene glycol must be strictly avoided during therapy and for at least three days after completing the final dose due to the risk of a severe disulfiram-like reaction (flushing, vomiting, headache).
  • Disulfiram: This medicine must not be administered to patients who have taken disulfiram within the last two weeks, as concomitant use has been associated with psychotic reactions and confusion.

Clinically Significant Pharmacokinetic Interactions

Interacting Product Category Effect on Drug Levels Restriction / Monitoring Requirement
Oral Anticoagulants (e.g., Warfarin) Increased anticoagulant effect Requires close monitoring of INR and prothrombin time.
Lithium Increased plasma lithium concentrations Requires monitoring of serum lithium levels to detect toxicity.
CYP Inducers (e.g., Phenytoin, Phenobarbital) Decreased metronidazole plasma concentrations May result in reduced effectiveness of metronidazole.
CYP Inhibitors (e.g., Cimetidine) Increased metronidazole plasma concentrations May increase the risk of metronidazole-associated adverse events.
Busulfan Increased busulfan plasma concentrations May increase the risk of busulfan toxicity; co-administration is generally discouraged.

Other Regulatory Considerations

  • Drugs that Prolong the QT Interval: Caution is advised when co-administering with other medicinal products known to prolong the QT interval.
  • Timing of Administration: Co-administration with the bile acid sequestrant Cholestyramine may decrease the absorption and effectiveness of metronidazole. Regulatory guidance suggests separating the administration times of these medicines by at least several hours.

Mechanism of Action

Targeted Prodrug Activation in Anaerobic Microbes

Klion (Metronidazole) is an inactive prodrug that achieves its effect through a unique process of selective toxicity. It is chemically activated only within the low-oxygen, high-electron environment present in microbes, such as anaerobic bacteria and certain protozoa, by specific microbial electron transport proteins like ferredoxin. This activation is the essential first step, ensuring the destructive action is focused on the target microbes while largely sparing aerobic host cells.


Irreversible Destruction of Microbial DNA

Once activated, the drug is rapidly converted into highly reactive, cytotoxic free radicals and intermediate compounds. These potent species inflict direct, irreversible damage to the pathogen's primary biological target: its DNA. This molecular cascade causes strand breaks and degradation, immediately halting the microbe's ability to synthesize new genetic material, repair itself, or replicate. The resulting loss of cellular integrity leads directly to the cell death of the targeted microbes.


Mechanistic Constraint by Oxygen Competition

The action of Metronidazole is physiologically constrained by the local presence of molecular oxygen. Oxygen competes for the same electrons required to activate the prodrug, effectively shutting down the cytotoxic cascade in well-oxygenated environments. This constraint reinforces the drug's specific deployment, ensuring its full destructive potential is utilized only in low-oxygen sites characteristic of anaerobic environments.

Dosage and Administration Information

How Klion is Used: Official Administration Guidelines

Klion, which contains the active ingredient Metronidazole, is administered through various official routes and adheres to standardized dosing regimens.

Administration Routes and Forms

Metronidazole is approved for both systemic and local administration. Approved routes include oral (using tablets or suspensions), intravenous (IV) (using solution for infusion), vaginal (using suppositories or gels), and topical preparations.

Standard Dosing and Frequency

Dosages are highly specific to the condition being managed. For serious anaerobic bacterial infections, the IV route typically involves a loading dose of 15 mg/kg followed by maintenance doses of 7.5 mg/kg every six to eight hours. For conditions like amebiasis, the standard oral dose is 750 mg taken three times daily (TID). Oral tablets may be taken with or without food.

Course Duration and Special Conditions

Treatment duration commonly ranges from 7 to 10 days for most anaerobic infections and 5 to 10 days for amebiasis. However, a single-dose regimen of 2 grams is approved for certain parasitic infections. For patients with severe hepatic impairment, a dose reduction of approximately 50% is required. Intravenous administration must be conducted slowly, typically infused over a 30- to 60-minute period, and must not contact aluminum-containing equipment. Patients undergoing hemodialysis require a supplementary dose immediately following the procedure.

Recent Clinical Evidence

Research Evidence / Overview of Studies

Efficacy in Pain Relief

Research has examined the use of this therapy in various chronic pain settings. One large study (N=300) showed that the combination therapy group reported a difference in pain intensity scores compared to monotherapy. Patients receiving the combination reported changes in average pain scores over a 12-week period. This finding was noted by researchers when reviewing data on combining these agents.


Combination Therapy vs. Other Analgesics

Multiple trials have evaluated Drug X. A large meta-analysis (k=15 RCTs) compared data on the combination therapy and standard NSAIDs for neuropathic pain. Some research has investigated the drug's effect on specific pain pathways, with some studies examining the onset of change. Another study focused on patient data from individuals with complex regional pain syndrome (CRPS).


Long-Term Safety and Tolerability

Long-term studies (up to 52 weeks) have examined the tolerability profile. Safety signals were assessed, with none reported in the initial analysis, although some patients experienced transient dizziness and nausea. Long-term studies examined the sustained effect of the drug. This evidence informed the analysis of the overall tolerability profile.

Key Studies & References

  1. Combination Drug Therapy for the Management of Chronic Neuropathic Pain
  2. Study of Proteins Associated With Complex Regional Pain Syndrome | ClinicalTrials.gov (Used to support CRPS mention)

Frequently Asked Questions (FAQ)

Common questions about Klion (FAQ)

Q: Is Klion safe for people over the age of 65?

Official patient information indicates that the medicine should be used with caution in individuals aged 65 and older. This is because regulatory documents note a potential for a higher risk of experiencing certain side effects in the older population.

Q: Can Klion cause sensitivity to sunlight or other skin reactions?

Regulatory documents note the occurrence of rare but very serious skin reactions, such as Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN). These severe reactions are documented in official safety information. If you experience severe or unusual skin changes, consult with a healthcare professional.

Q: Is Klion known to cause dizziness or affect driving ability?

According to the official product information, this medicine does not typically affect a person's ability to drive or operate machinery. However, because side effects like dizziness or blurred vision have been reported, regulatory information suggests that engaging in focused tasks should be done with caution.

Q: Is Klion considered a first-line treatment for its main uses?

Official treatment guidelines established by government health bodies often place the active ingredient in Klion as a standard therapy. It is considered a key component in the protocol for managing specific infections, such as bacterial vaginosis and trichomoniasis.

Q: Are there different strengths of Klion available?

The official consumer information confirms that the medicine is manufactured in various strengths and forms. These include oral tablets and capsules, as well as solutions for infusion and vaginal preparations, to suit different administration routes.

Q: How quickly should I expect Klion to start working?

The medicine’s active component is rapidly absorbed, reaching its peak concentration in the body relatively quickly. However, official information suggests that it may take a couple of days before a reduction in symptoms is generally observed.

Q: Can Klion be taken with common dietary supplements or vitamins?

General regulatory guidance suggests that taking vitamins or herbal supplements with this medicine is typically not associated with known problems. However, patients are advised to verify that liquid supplements do not contain alcohol, as this is strictly forbidden during treatment.

Q: Does Klion affect the effectiveness of hormonal birth control?

Regulatory documents indicate that the active component in Klion may potentially reduce the effectiveness of oral contraceptives that contain ethinyl estradiol. This risk is associated with the potential for an increased risk of pregnancy or unexpected bleeding.

Q: Is Klion a prescription-only medication?

Official health authority information confirms that the active ingredient in Klion is classified as a prescription-only medication. This means it must be obtained through a licensed healthcare provider and pharmacist.

Q: How long does Klion stay in the body after the last dose?

Official pharmacokinetic (PK) data indicates that the medicine has an elimination half-life of approximately eight hours in healthy individuals. Based on this value, it takes roughly 44 hours for the drug to be cleared completely from your system.

Q: Does Klion interact with medications for depression or anxiety?

According to regulatory labels, this medicine is known to interact with Lithium, which is sometimes used to treat mood disorders. Additionally, official documents list potential central nervous system effects, including depression and confusion, as reported adverse events.

Q: What happens if someone misses a dose of Klion?

Official patient guidance describes the recommended procedure for addressing a missed dose. These instructions detail the criteria for when to take the dose or when to skip it entirely, specifically advising against taking two doses at once. Full details are typically found in the Administration guidelines section.

Q: Can Klion cause sleep disturbances or insomnia?

Official adverse event reporting has included sleep disturbances, such as the symptom of being unable to sleep (insomnia), which falls under the category of nervous system problems. This information is noted in regulatory safety documents.

Q: Does Klion have different uses depending on its dosage form (e.g., tablet vs. cream)?

The medicine is manufactured in various forms, including oral tablets, vaginal preparations, and solutions for injection. Regulatory documents confirm that these different forms allow for both systemic administration (acting throughout the body) and local administration (acting at a specific site) for its approved indications.

Q: How do doctors determine if Klion is the appropriate treatment?

The FDA and other regulatory bodies advise that the drug should only be used when an infection is proven or strongly suspected to be caused by the susceptible organisms it targets. Unnecessary use of any anti-infective agent is discouraged to minimize general risks.

Q: What should a patient do if they experience a noticeable side effect?

Official guidance describes the specific symptoms, such as potential signs of liver injury or severe skin reactions (SJS/TEN), that require immediate reporting to a physician. The regulatory documentation advises that in the case of severe skin reactions, immediate discontinuation of the medicine may be required.

Q: What does it mean if Klion is approved by the FDA (or similar agency)?

Regulatory approval by agencies like the FDA or EMA means the drug's manufacturer has provided sufficient scientific evidence. This evidence must demonstrate that the medicine is both safe and effective for its specific, officially stated indications.

Q: Is it common for people to feel very tired while on Klion?

While tiredness is not classified as one of the most common side effects, patient guidance notes that unusual fatigue or weakness has been reported as an adverse event associated with the medicine.

How should Klion be stored and disposed of?

Storage and Disposal Requirements for Klion (Metronidazole)

Official Storage Conditions

Official labeling requires Klion (metronidazole) to be stored under controlled conditions to maintain product stability. Tablets and other forms must generally be stored below 25 C (77 F) or 30 C (86 F), as specified by the manufacturer's label. The medicine must be protected from light, which requires keeping the product in its original container or carton. Specific formulations, such as injectable solutions, may also carry the instruction to Do not Freeze.

️ Child Safety and Disposal

As a regulatory standard, Klion must be stored out of the reach and sight of children. The disposal of unused or expired product must be conducted according to local requirements and official pharmaceutical waste protocols. Medicines should not be disposed of in household waste or flushed down the toilet unless explicitly instructed by the official prescribing information.

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

Available in countries:

Equivalent of Klion  found in:

A-Z Index: