Claromycin

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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 Claromycin

Quick Facts

Property Description
Active Ingredient Clarithromycin
Form Oral tablet, Oral suspension, Intravenous solution
Pharmacological Class Macrolide Antibiotic
General Purpose To combat bacterial infections
Origin Semi-synthetic (derived from Erythromycin)

What Type of Drug is Claromycin, and What is its Composition?

Claromycin is the trade name for a medicine containing the active ingredient Clarithromycin, which is precisely classified as a macrolide antibiotic. This compound is defined as a semi-synthetic drug, synthesized from the naturally occurring macrolide, Erythromycin, placing it firmly within the broader class of anti-infective agents. As an Erythromycin derivative, Clarithromycin is used to treat a wide range of bacterial infections; its chemical structure includes a 6-O-methyl group, which enhances its stability compared to its predecessor.

Clarithromycin is typically provided as a single-entity product and is formulated for systemic administration to function throughout the body. It is available in various pharmaceutical preparations, including common oral tablets, liquid oral suspensions (often prepared from granules), and a specialized intravenous solution for clinical use. As a prescription-only medicine, Claromycin requires professional authorization, ensuring its targeted use in adults and pediatric patients when bacterial infection is confirmed.


Claromycin's General Role: Combatting Bacterial Infections

The general purpose of Claromycin is to provide effective pharmacological support to combat systemic bacterial infections caused by organisms sensitive to its action. The drug achieves this by functioning primarily as a bacteriostatic agent, which serves to stop or inhibit the bacteria's ability to grow and multiply. Macrolide antibiotics, including Clarithromycin, are utilized as treatments for infections caused by susceptible bacteria.

This targeted effect is due to its specific mechanism principle: Clarithromycin enters the bacterial cell and binds to the crucial 50S ribosomal subunit, thereby blocking the bacteria's capacity to manufacture the essential proteins needed for survival and division. By effectively halting this protein synthesis, Claromycin limits the progression of the infection, allowing the body's natural immune defenses to successfully clear the static bacterial population and resolve the underlying infectious condition.

What side effects are possible with Claromycin?

Possible Side Effects and Safety Information

The official safety profile of Claromycin (clarithromycin) classifies adverse reactions by frequency and the body system affected, based on regulatory documentation from agencies such as the EMA and FDA. These classifications define the scope of possible reactions, from commonly reported issues to rare, serious events.


Adverse Reaction Classification

Classification Examples of Reactions
Very Common Taste perversion (dysgeusia).
Common Headache, insomnia, diarrhea, vomiting, nausea, and abdominal pain.
Uncommon Palpitations, dizziness, hepatitis, rash, and pruritus.
Frequency Not Known Hepatic failure (potentially fatal), acute pancreatitis, ventricular arrhythmias including Torsades de pointes, and rhabdomyolysis.

Adverse effects are also grouped by System-Organ Class, with documented risks across Gastrointestinal disorders, Hepatobiliary disorders (liver), Cardiac disorders, Nervous System disorders, and Skin and Subcutaneous Tissue disorders.


Key Safety Constraints and Considerations

The medicine's use is subject to specific regulatory limitations. It is officially contraindicated in individuals with a history of QT prolongation, pre-existing ventricular arrhythmia, or uncorrected electrolyte disturbances such as hypokalemia. Usage is also contraindicated in patients with severe hepatic failure in combination with renal impairment.

Safety notes also exist for particular populations. The FDA has documented a potential long-term cardiovascular risk observed in some patients with pre-existing coronary heart disease, which became apparent one year or longer after a short course of treatment. Caution is additionally advised for elderly patients due to heightened susceptibility to cardiotoxicity and specific drug interactions.

Overdose and Emergency Response

Overdose and when to seek help

Regulatory documents define the Claromycin overdose profile based on documented clinical manifestations and the potential for serious outcomes. Acute overdose is primarily characterized by severe gastrointestinal symptoms, including abdominal pain, nausea, vomiting, and diarrhea.


Documented Severe Outcomes and Required Action

Overdose carries a documented risk of serious cardiac effects, specifically QT interval prolongation and the potential development of ventricular arrhythmias, such as Torsade de Pointes. These severe manifestations necessitate specialized monitoring.

Immediate medical attention is required upon confirmed or suspected overdose. The drug must be immediately discontinued to prevent further exposure. As no specific antidote is known for Claromycin overdose, official management consists entirely of symptomatic and supportive treatment to stabilize the patient's condition.

Overdose effects may be exacerbated in patients with pre-existing renal impairment due to altered drug clearance, which can lead to increased serum concentrations and heightened risk of toxicity.

Supportive procedures described in official labeling may include the use of gastric lavage and the administration of activated charcoal, with continuous ECG monitoring required to observe cardiac status.

Therapeutic Uses of Claromycin

What Claromycin Treats: Main Uses and Benefits

Claromycin (clarithromycin) is a prescription antibacterial medicine that may be used to address various susceptible bacterial infections. Its primary role is in managing conditions caused by specific susceptible organisms, contributing to the resolution of the infection.

Quick Facts

  • Supports management of upper and lower respiratory tract infections, including certain types of pneumonia, sinusitis, and bronchitis.
  • May be used to treat skin and soft tissue infections.
  • Assists in the eradication of Helicobacter pylori bacteria in patients with duodenal ulcers, typically as part of a combination regimen with other agents.
  • Can be utilized for the treatment and prevention of disseminated Mycobacterium avium complex (MAC) infection, especially in individuals with advanced HIV infection.
  • A therapeutic option for pharyngitis (throat infection) and tonsillitis in individuals who cannot tolerate first-line treatments.

Claromycin is indicated for use in both adults and pediatric patients for appropriate infections. This medication functions to inhibit the growth of bacteria, which assists the body in recovering from the illness. It is important to note that Claromycin does not address viral infections such as the common cold or flu.

Eligibility and Restrictions for Use

Who Can and Cannot Use Claromycin?

Population eligibility for Claromycin (clarithromycin) is determined by regulatory-mandated restrictions detailed in official prescribing information.

Eligibility Scope Status Based on Regulatory Documents
Populations Contraindicated Strictly prohibited for patients with a known macrolide hypersensitivity, including allergy to clarithromycin or erythromycin. Contraindicated for individuals with specific cardiac risks, such as congenital or acquired QT prolongation, or a history of ventricular arrhythmia or torsades de pointes. Also contraindicated in patients with severe hepatic failure combined with renal impairment, and those with a history of clarithromycin-associated cholestatic jaundice.
Age-Related Rules Not recommended/use not established for children younger than 6 months of age. Adult tablets and Extended-Release (ER) formulations are not suitable for children under 12 years.
Condition-Specific Rules Use requires caution in patients with isolated hepatic impairment or severe renal impairment (creatinine clearance < 30 mL/min). Caution is also advised for those with uncorrected hypokalaemia or hypomagnesaemia.
Reproductive Status Use during pregnancy is generally not advised unless the benefit is carefully assessed to outweigh the risk. Clarithromycin is excreted into human breast milk, which may require discontinuation of nursing.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Clarithromycin is documented to interact with numerous medicines, primarily due to its effect as a strong inhibitor of the CYP3A4 enzyme and a P-glycoprotein (P-gp) inhibitor. This action leads to increased blood levels of many co-administered drugs that are substrates for these systems, resulting in a higher risk of adverse reactions.

Contraindicated Combinations

The following medicines are officially contraindicated (must not be used) with Clarithromycin due to the risk of serious or life-threatening events:

Interaction Type Examples of Affected Medicines
Increased toxicity/Rhabdomyolysis Simvastatin, Lovastatin (certain HMG-CoA reductase inhibitors)
Increased cardiovascular risk Astemizole, Cisapride, Quinidine, Disopyramide (certain antiarrhythmics)
Acute toxicity Ergotamine, Dihydroergotamine (ergot alkaloids)

Other Clinically Significant Interactions

Co-administration with other medicines that are known to prolong the QT interval (e.g., Amiodarone, Sotalol) is generally not recommended due to the potential for an additive effect on cardiac rhythm.

Clarithromycin also significantly increases the exposure of Colchicine; this combination is strictly contraindicated in patients with kidney or liver impairment.

Medicines that induce CYP3A4 (e.g., Rifampicin, Efavirenz) can decrease Clarithromycin levels, potentially reducing its effectiveness. Conversely, strong CYP3A4 inhibitors like Ritonavir increase Clarithromycin exposure.

Patients taking the HIV medicine Zidovudine must take it at least two hours apart from Clarithromycin to ensure proper absorption.

Mechanism of Action

Primary Mechanism: Inhibiting Bacterial Protein Synthesis

Clarithromycin functions as an inhibitor by specifically binding to the 50S ribosomal subunit within susceptible bacteria, effectively arresting the crucial translocation step of protein synthesis. This molecular block prevents the bacteria from manufacturing essential proteins required for growth and replication, leading to a bacteriostatic effect that limits the microbial population density.


Secondary Mechanism: Modulation of Host Inflammation

Beyond its antimicrobial role, the drug accumulates in host immune cells (e.g., neutrophils) and acts as a modulator of inflammatory pathways. This mechanism influences the cellular release of pro-inflammatory cytokines (like IL-8) and alters associated neutrophil activity. This secondary action modulates the cellular inflammatory response and influences associated physiological reactions triggered by the presence of bacteria.


Active Metabolite and Mechanistic Constraints

The drug's activity is supported by its active metabolite, 14-hydroxyclarithromycin, which operates in a complementary manner by targeting the identical ribosomal subunit, which results in enhanced total 50S ribosomal inhibition. However, this core mechanism can be functionally constrained when bacteria develop resistance, such as modifications to the ribosomal target itself (methylation) or the activation of efflux pumps that actively expel the drug from the cell before it can bind.

Dosage and Administration Information

How to Use Claromycin

Clarithromycin (Claromycin) is a prescription medicine administered via the oral route (tablets or suspension) or by intravenous (IV) infusion in clinical settings. The medication is utilized according to specific dosing, frequency, and administration parameters.


Official Administration Guidelines

Feature Oral Immediate-Release (IR) & Suspension Oral Extended-Release (ER)
Standard Adult Dose Typically 250 mg to 500 mg per dose. Typically 1000 mg once daily.
Frequency Pattern Generally administered every 12 hours (Twice Daily). Administered every 24 hours (Once Daily).
Timing in Relation to Meals May be taken with or without food. Must be taken with food.
Procedural Condition Oral Suspension must be shaken well before use. Must be swallowed whole; do not crush, break, or chew.
Course Duration Usually ranges from 7 to 14 days. Usually ranges from 7 to 14 days.

Population-Specific Rules

  • Pediatric Patients: For children older than 6 months, the dose is generally calculated based on body weight, commonly 15 mg/kg/day in two divided doses, using the oral suspension.
  • Renal Impairment: In adult patients with severe kidney problems (creatinine clearance < 30 mL/min), the dosage is typically reduced by one-half, and treatment usually does not continue beyond 14 days.

When a dose is missed, it is typically taken as soon as possible, unless it is nearly time for the next scheduled dose, in which case the missed dose is skipped to resume the normal schedule; double doses are not taken.

Recent Clinical Evidence

Claromycin: Recent Clinical Evidence

The following overview describes the structure of clinical research for Claromycin (clarithromycin), detailing the types of studies performed, the measured outcomes, and the limitations noted in the research landscape.


Evidence for Respiratory Tract Infections

The research landscape includes randomized controlled trials (RCTs) and comparative studies where the medicine was studied for infections such as pneumonia, bronchitis, and sinusitis. Studies monitored outcomes related to physical discomfort and changes in patient-reported symptom scores over short intervals. Findings describe patterns observed in these studies compared to other treatments, but data for certain groups, such as very young children with community-acquired pneumonia, remain insufficient. Research provides insight into short-term changes, but there is limited information for long-term outcomes.


Evidence for Treating H. pylori Bacteria

Claromycin was studied for its role in the eradication of Helicobacter pylori bacteria as part of a multi-drug regimen. Studies monitored the confirmation of bacterial eradication as the primary outcome. Findings describe patterns related to eradication rates, but evidence suggests the measured change is highly dependent on the local prevalence of resistant strains and requires use within a specific combination regimen. Evidence quality varies across studies, and uncertainty exists due to rising global resistance rates, which introduces variability when applying historical research findings.


Evidence in Specialized Populations and Research Gaps

Research explored the use of Claromycin in specific patient groups, including pediatric populations and adults with specialized health conditions, such as advanced HIV infection (for MAC management). The body of research related to MAC is specialized, and results apply primarily to those populations studied. Overall, for most indications, the follow-up durations were limited, meaning that long-term effects are not fully established. A primary area of uncertainty across the research landscape is the real-world impact of the increasing bacterial resistance, which is an ongoing focus of research.

Key Studies & References

  1. Clarithromycin: overview and its current clinical utility in the treatment of respiratory tract infections
  2. Clarithromycin in the treatment of skin and skin structure infections: two multicenter clinical studies. Clarithromycin Study Group
  3. Disseminated Mycobacterium avium Complex: Adult and Adolescent OIs | NIH - Clinical Info .HIV.gov

Frequently Asked Questions (FAQ)

Common questions about Claromycin (FAQ)


Q: What is the main difference between Claromycin and a standard antibiotic?

Claromycin is classified as a macrolide antibiotic. This means it is part of a specific group of anti-infective agents that function by stopping the growth of bacteria, rather than immediately killing them. Official information notes that this drug is a semi-synthetic compound, chemically derived from the naturally occurring macrolide, Erythromycin.


Q: Can Claromycin interact with common over-the-counter pain relievers?

The drug is known to interact with medicines that are processed in the body by the CYP3A4 enzyme system. Because this mechanism can increase blood levels of co-administered drugs, the regulatory documents reflect the need for caution when co-administering all medicines, including non-prescription and over-the-counter products, due to the risk of potential interactions.


Q: Why is Claromycin sometimes prescribed for non-infectious conditions?

Official information describes a secondary action of the medicine as a modulator of inflammatory pathways within host immune cells. This influences the body's cellular inflammatory response, which is a separate, researched effect. However, the approved indications listed in regulatory documents are strictly for the treatment of bacterial infections.


Q: Do studies suggest any specific risk factors that make side effects more likely with Claromycin?

Regulatory documents identify certain populations who have a heightened risk of complications. These include individuals with a history of QT prolongation, uncorrected electrolyte imbalances (such as low potassium or magnesium levels), or pre-existing severe kidney or liver impairment. Official documents also note heightened risk for elderly patients due to their increased susceptibility to certain risks.


Q: What is the official guidance on when to stop taking Claromycin treatment?

Regulatory guidance specifies a treatment duration, typically ranging from 7 to 14 days, and reflects that the full prescribed course is generally required. Stopping treatment early, even if symptoms improve, is noted as potentially increasing the risk of the underlying infection not being fully resolved.


Q: What does the patient information leaflet say about allergic reactions to Claromycin?

Patient information describes the signs of a severe allergic reaction (anaphylaxis), such as swelling of the lips, tongue, or throat, or trouble breathing. It also describes serious skin reactions, such as blistering or peeling skin. These are serious adverse events that regulatory sources advise should be addressed immediately.


Q: How does the TGA or Health Canada classify the overall safety of Claromycin?

Regulatory information from agencies like Health Canada includes specific serious warnings and precautions. These address the drug’s use in pregnancy, potential drug interactions with other prescribed medicines (such as Quetiapine), and use in patients with pre-existing heart rhythm disturbances or severe liver/kidney failure.


Q: What is the difference between a side effect and a contraindication for Claromycin?

A side effect is a reported reaction that may occur during the use of the medicine, classified by its frequency (e.g., common or uncommon). A contraindication is a specific, pre-existing medical condition or co-administered medicine (e.g., QT prolongation) that makes the use of the drug strictly prohibited due to the high risk of a serious adverse event.


Q: Is Claromycin safe for people who have a history of certain psychological conditions?

Official warnings contain specific warnings regarding co-administration with specific medicines prescribed for mood disorders (e.g., Quetiapine) due to the risk of serious side effects from elevated drug levels. The regulatory safety profile also notes potential central nervous system effects, including insomnia, dizziness, and hallucinations.


Q: How quickly should I expect to feel better after starting Claromycin?

Patient information indicates that individuals generally begin to feel better during the first few days of treatment. If symptoms do not improve or begin to worsen after starting the medicine, regulatory information notes that worsening symptoms should be discussed with a qualified healthcare provider.


Q: How long does Claromycin stay in your system after the last dose?

The time the drug stays in the body is described by its elimination half-life, which ranges from approximately 3 to 7 hours, depending on the dose taken. The active metabolite, 14-hydroxyclarithromycin, has a longer half-life, which can range from 5 to 9 hours.


Q: What happens if Claromycin is taken with alcohol, according to regulatory warnings?

Regulatory information generally indicates that alcohol does not reduce the direct effectiveness of this medicine. However, because alcohol may slow the body's natural recovery process from an infection, regulatory documents describe that avoiding consumption may support the body's natural recovery process from the infection.


Q: What are the typical conditions or infections that Claromycin is approved to treat?

According to official documentation, the medicine is approved to treat certain bacterial infections including those of the ears, sinuses, skin, and throat, as well as lung infections such as pneumonia and bronchitis. It is also approved for use in combination with other drugs for the eradication of H. pylori bacteria.


Q: Can Claromycin affect the effectiveness of oral contraceptives?

Official guidance indicates that this medicine does not directly stop most hormonal contraceptives from working. However, if Claromycin causes severe vomiting or diarrhea, regulatory information suggests that a reduction in protection is possible, which may require additional consideration.


Q: Why is Claromycin sometimes prescribed alongside a probiotic?

Regulatory resources note that taking oral probiotic preparations and antibiotics concurrently may reduce the effectiveness of the probiotic. Consequently, prescribing patterns may reflect a recommendation to separate the dose timings (e.g., 1 to 2 hours apart) to allow the probiotic to support its activity, often to help manage potential gastrointestinal side effects.


Q: Is Claromycin known to interact with caffeine or high-acid drinks?

Official guidance specifically indicates that consuming grapefruit juice may delay the drug’s absorption and the time it takes to reach peak plasma concentration in the blood. Although the overall amount absorbed may not be affected, official patient information highlights this potential delay.


Q: Can Claromycin be used for recurrent infections, based on official recommendations?

The full prescribed course of treatment is understood as necessary to complete to effectively treat the initial acute infection and reduce the risk of the bacteria developing resistance. Regulatory information focuses on treating the acute infection rather than providing explicit guidance on the use of the medicine for recurring infections.


Q: What does the SmPC say about Claromycin's primary metabolic pathway?

Official prescribing information (such as the Summary of Product Characteristics, SmPC) notes that the medicine is primarily processed and broken down in the body by cytochrome P450 (CYP) 3A enzymes. This metabolic pathway is a key reason why it interacts with numerous other medicines that utilize the same system.


Q: Is Claromycin considered a 'broad-spectrum' or 'narrow-spectrum' medicine?

While the official label does not strictly use these terms for classification, Claromycin is noted to be effective against a range of aerobic Gram-positive and Gram-negative bacteria, as well as other atypical organisms. Its spectrum of activity depends on the specific approved indication.

How should Claromycin be stored and disposed of?

Storage and Disposal of Clarithromycin

Clarithromycin (Claromycin) must be stored and handled according to specific regulatory requirements to maintain its stability.


Storage Conditions

Clarithromycin tablets should be stored at controlled room temperature, typically 20 C to 25 C (68 F to 77 F), kept in the original container with the lid tightly closed, and protected from light. All forms of the medicine must be kept out of the sight and reach of children.

Suspension Stability

The prepared liquid oral suspension must not be refrigerated or frozen. Once mixed, the suspension is stable for 14 days when stored at room temperature (15 C to 30 C), and any remaining portion must be discarded after this period.

Disposal

Unused or expired clarithromycin must be disposed of safely. The FDA recommends using a drug take-back program. It is specified that this medication must not be flushed down the toilet or poured down a drain.

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

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