Herpesan

Carbenoxolone

Method of action: Anti-Inflammatory

Treatment option: Stomatitis

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 Herpesan

What is Herpesan? Definition and Active Ingredient

Property	Description
Active ingredient	Carbenoxolone sodium
Form	Gel (Aqueous base)
Pharmacological class	Anti-ulcer agent; Triterpenoid derivative
General purpose	Local relief and mucosal protection
Origin	Synthetic derivative of glycyrrhetinic acid

Herpesan is a single-ingredient medicinal preparation defined by its active pharmaceutical component, Carbenoxolone sodium (INN). This substance is classified as an anti-ulcer agent and a triterpenoid derivative under the Anatomical Therapeutic Chemical (ATC) code A02BX01. The drug's classification reflects its unique chemical structure, which is recognized for its localized anti-inflammatory activity.

Carbenoxolone sodium is a well-established compound in this therapeutic area. The specific formulation in the Herpesan brand is positioned as a direct-acting topical agent, often intended for individuals seeking relief from common painful surface lesions, such as recurring mouth sores.

Carbenoxolone: Origin, Type, and Physical Form

The core compound, Carbenoxolone, is a synthetic derivative chemically adapted from glycyrrhetinic acid, a triterpenoid substance naturally isolated from the licorice root. Herpesan is specifically supplied as a viscous, water-soluble gel, making it a preparation designed solely for topical administration to affected areas.

The deliberate choice of this form and route of administration differentiates the current product from similar agents that may be administered systemically. The use of an aqueous gel base facilitates easy and precise application, ensuring the active component remains localized to the required site, which is essential for focused surface treatment of the mucosa.

General Purpose and Soothing Action

The general purpose of Herpesan is to provide localized relief and support the natural restoration of damaged superficial tissues. This is achieved through the drug’s primary principle of delivering anti-inflammatory action and a protective effect over the compromised surface. The protective mechanism is associated with stabilizing cell membranes and promoting tissue integrity, aiding the body's healing process. By helping to mitigate local swelling and irritation and supporting the structural integrity of the damaged mucosa, the compound minimizes the discomfort typically associated with painful oral or labial lesions. Essentially, the medicine serves as a focused topical solution intended to soothe local distress and encourage the natural restoration of the tissue.

What side effects are possible with Herpesan?

Possible Side Effects and Safety Information

The safety profile of Herpesan, which contains Carbenoxolone sodium, is primarily defined by the known systemic effects of the active ingredient, even though it is formulated for topical application. The most commonly documented adverse reactions relate to the potential for electrolyte imbalance and subsequent effects on the cardiovascular system.

Official Regulatory Safety Classifications

Adverse Reaction Type	Classification / System	Details
Common Effects	Metabolism & Vascular Disorders	Fluid retention (oedema), Hypokalaemia (low potassium), and Hypertension (high blood pressure)
Uncommon Effects	Gastrointestinal & Nervous Systems	Headache, nausea, and vomiting
Serious Adverse Reactions	Cardiovascular & Musculoskeletal	Severe Hypokalaemia may lead to serious events, including cardiac arrhythmias and, rarely, rhabdomyolysis

Safety Considerations and Restrictions

The documented systemic risks are predominantly associated with high doses or long-term exposure to the active substance, as specified in regulatory information. The safety profile identifies certain populations as being more susceptible to these effects. Older adults may be at increased risk of hypokalaemia and fluid retention. Furthermore, caution is officially advised, or the medicine may be contraindicated, in patients with pre-existing conditions such as severe renal impairment, uncorrected hypokalaemia, or severe hypertension.

The official safety information highlights that the risk of low potassium is explicitly increased when the active substance is used concurrently with other medicines known to cause potassium loss, such as certain diuretics.

This framework ensures the official safety documentation addresses potential systemic risks, structuring the overall safety profile around the active substance's impact on fluid and electrolyte regulation.

Overdose and Emergency Response

Overdose and When to Seek Help — Official Regulatory Information

The following information is derived from authoritative governmental regulatory documents regarding the management and symptoms of an overdose of Acyclovir (Herpesan).

Documented Overdose Manifestations

Symptoms reported following overdose, particularly with excessive intravenous infusion or high oral doses, affect multiple systems:

Renal: Elevated BUN and serum creatinine, and the potential for renal failure due to crystallization in the renal tubules.
Neurological: Central nervous system effects including headache, confusion, agitation, somnolence, tremors, hallucinations, seizure, and coma.
Gastrointestinal: Common symptoms are nausea and vomiting.

When to Seek Immediate Medical Help

In the event of a suspected overdose, contact a Poison Control Center or Emergency Room at once. Immediate medical assistance must be sought if the individual has collapsed, had a seizure, has trouble breathing, or cannot be awakened.

Overdose Management and Considerations

There is no specific chemical antidote for Acyclovir overdose. Management is supportive. In severe cases, the drug is officially documented as being removable by hemodialysis. Patients with pre-existing renal impairment and elderly individuals are noted to be at higher risk for severe neurological toxicity and accumulation.

Therapeutic Uses of Herpesan

What Herpesan Treats: Main Uses and Benefits

Herpesan (Carbenoxolone sodium gel) is used in applications where symptomatic support is required for surface lesions. The medication is commonly utilized for symptomatic relief in situations involving recurrent or episodic manifestations, such as mouth ulcers (canker sores) and lip sores. It is applied to address symptoms related to physical discomfort and irritative states, including localized pain and swelling that accompany a lesion outbreak.

The medication is relevant in settings involving acute or unstable symptom patterns that may create physiological strain and temporarily affect daily functioning. The core benefit is providing supportive relief by assisting with surface protection over the compromised area. This supports the management of symptomatic periods by easing local distress and contributing to improved comfort during the course of the episode.

Quick Fact: Relief for Localized Pain and Symptom Intensity

Regulatory References

official regulatory information from the Health Products Regulatory Authority (HPRA)

Eligibility and Restrictions for Use

Eligibility for Herpesan (Carbenoxolone Sodium Gel)

Official regulatory documents define specific populations who are permitted, restricted, or prohibited from using Herpesan.

Contraindications (Must Not Use) The medicine is strictly contraindicated for individuals with a known hypersensitivity (allergy) to Carbenoxolone sodium or any of its ingredients. Absolute non-eligibility is also stated for patients with severe renal impairment (severe kidney dysfunction) or those with known or suspected conditions involving mineralocorticoid excess.

Age and Population Restrictions Use is approved for adults and adolescents aged 12 years and over. The medicine is not recommended for use in children under 12 years of age due to insufficient supporting data. It is also not recommended for women who are breastfeeding. During pregnancy, particularly the first trimester, use is restricted and should only occur if the potential benefit to the mother outweighs the possible risk.

Conditional Use (Use with Caution) Patients with a history of cardiac failure, hypertension (high blood pressure), or those with or predisposed to hypokalaemia (low potassium levels) must use Herpesan with caution, as these conditions may increase the potential for systemic effects.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Officially documented interaction patterns for Carbenoxolone sodium, the active ingredient in Herpesan, are primarily related to its potential to induce a systemic mineralocorticoid-like effect, which can lead to fluid retention and low potassium levels (hypokalaemia). While Herpesan is a topical gel, its official regulatory profile includes these interaction warnings, typically associated with the systemic activity of the compound.

Official Interaction Statements and Restrictions

The following interaction patterns are documented in regulatory sources:

Contraindicated Combinations: Co-administration with Digitalis Glycosides (or Cardiac Glycosides) is contraindicated. This restriction is due to the severe risk of increased cardiac glycoside toxicity resulting from Carbenoxolone-induced hypokalaemia.
Pharmacodynamic Potentiation: Concomitant use with Diuretics (Loop and Thiazide types) or Corticosteroids may potentiate the risk of developing hypokalaemia due to additive effects on electrolyte balance.
Antagonistic Effects: Carbenoxolone sodium may exhibit an antagonistic action toward Mineralocorticoid Antagonists (such as Spironolactone and Amiloride), potentially reducing their therapeutic efficacy.
Impact on Efficacy: The blood pressure-lowering action of Antihypertensive Medications may be antagonized and reduced.

Population-Specific Interaction Notes

Interaction-related risks are officially noted as heightened for patients with pre-existing severe heart, liver, or kidney complaints, as they are more susceptible to the consequences of electrolyte and fluid imbalance that define these interactions.

Mechanism of Action

Inhibition of Viral Replication Cascade

Herpesan's primary pharmacodynamic activity covers direct inhibitory action at the molecular level, where the molecule functions as an enzyme-mediated signaling inhibitor. The drug selectively accumulates within targeted cells and interferes with early molecular steps by targeting viral DNA polymerase activity. This interaction is required for the assembly and replication of the pathogen's genetic material. This mechanism modifies the viral replication cycle, thereby altering signaling sequences and modifying the downstream production of new virions.

Modulation of Pathway Mediator Activity

This domain involves Herpesan's modulation of host cellular processes involving localized or systemic mediator activity. The drug engages mechanisms that regulate inflammation-associated processes, potentially by modulating or interfering with key inflammatory signaling pathways within the targeted tissues. This activity results in a shift toward reduced mediator activity, which modifies the scope of excessive activity and promotes pathway-level regulation.

Dosage and Administration Information

How to Use Herpesan

Herpesan (Carbenoxolone sodium 2% w/w gel) is characterized by specific parameters that define the administration, dose, and frequency.

Administration Guidelines

Usage Parameter	Application Detail
Route of Administration	Topical and oromucosal use only, applied directly to sores in the mouth and on the lips.
Standard Dosing	Apply a quantity of the gel thickly to the affected lesion.
Frequency and Timing	Apply four times daily. Doses are timed after meals and at bedtime.
Initiation of Treatment	Application should begin at the first signs of symptoms (e.g., tingling or burning).
Application Technique	The gel must be allowed to remain on the affected area as long as possible to maximize contact time.

Duration and Age Restrictions

Clear limits are established regarding the duration and population for use.

Restriction	Detail
Age Group	Used in Adults and children over 3 years of age.
Duration Constraint	If the lesions fail to heal within 3 weeks, treatment should be reviewed by a healthcare professional.

These administration guidelines define a localized treatment approach. The regimen of applying a thick quantity four times daily, scheduled around meals, facilitates consistent application. Adhering to the specified procedural steps and age restrictions characterizes the standard application process.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Herpesan

Evidence for Use in Recurrent Oral Ulcers (Mouth Sores)

Herpesan gel, which contains the active ingredient carbenoxolone sodium, was studied for its application in conditions characterized by fluctuating or episodic manifestations, such as recurrent oral ulcers or mouth sores (minor aphthous stomatitis). The existing research base primarily includes short-term, randomized controlled trials (RCTs) and syntheses of these trials in systematic reviews. These studies were conducted in adult populations during periods of increased symptom activity.

Research examined several outcomes related to physical discomfort. Specifically, the trials monitored patient-reported outcomes describing perceived discomfort, such as changes in pain intensity, often measured using validated scales. Studies also explored physical measures including the size and number of lesions, which were monitored in the observed populations during the short-term follow-up periods.

Short-term follow-up in the trials typically spanned one to two weeks. However, scientific literature indicates that evidence for the specific topical formulation remains limited. Reviews have documented that sample sizes were small in some of the key research, and the evidence quality varies across studies, leading to a determination that certainty remains low regarding comprehensive findings. Research so far contributes to the broader evidence landscape but does not determine whether an individual will respond similarly.

The Role of Historical Research in Drug Classification

Carbenoxolone sodium's official classification as an "anti-ulcer agent" was derived from a distinct body of historical research. This research was studied for outcomes related to systemic or functional imbalance, such as duodenal ulceration. These systemic trials involved adult populations using the drug in a high-dose oral capsule form, a formulation different from the topical gel. While this research contributes to understanding the compound's pharmacological designation, the results apply only to the populations studied and the systemic administration route. Therefore, this older research is not directly applicable to the performance of the Herpesan topical gel, which is designed for localized surface treatment.

Durability and Long-Term Follow-up in Research

The research exploring short-term symptom changes in topical studies generally involved follow-up durations that were limited, often not extending beyond the acute symptomatic episode (typically one to two weeks). There is limited information for long-term outcomes regarding whether the application of the gel may influence the frequency or severity of future recurrence cycles, which are conditions characterized by fluctuating or episodic manifestations. The evidence available primarily provides insight into acute symptom patterns during the specific study period.

Key Studies & References

Frequently Asked Questions (FAQ)

Common questions about Herpesan (FAQ)

Q: What are the common side effects of Herpesan I should watch out for?

According to official regulatory safety classifications, the common effects documented for the active ingredient, Carbenoxolone sodium, are related to its potential systemic action. These effects include fluid retention (oedema), low potassium levels (hypokalaemia), and high blood pressure (hypertension). These are effects associated with the compound itself, even when it is used as a topical gel.

Q: What is the maximum number of days I can use Herpesan gel?

The official product information advises caution regarding long-term use. If symptoms or sores do not show signs of healing or persist after approximately 2 to 3 weeks of using the gel, the label indicates that treatment should be reviewed by a healthcare professional.

Q: What should I do if I miss a dose of the gel?

If a scheduled application is missed, the general guidance provided in the patient information leaflet is to apply the gel as soon as the missed dose is remembered. The guidance is to then continue by taking the next dose at the regularly scheduled time.

Q: Is Herpesan a prescription-only medicine?

The regulatory classification for topical carbenoxolone sodium varies across different countries and jurisdictions. In some areas, it may be classified as a prescription-only medicine (requiring a doctor's prescription), while in others, it may be available over-the-counter from a pharmacist.

Q: Can I use Herpesan for a cold sore that has already fully crusted over?

The official guidelines for this gel specify that application should begin at the very first signs of symptoms, such as the initial tingling or burning sensation. The medicine is indicated for the symptomatic relief and treatment of mouth ulcers and lip sores.

How should Herpesan be stored and disposed of?

Official Storage and Disposal Requirements

Storage and disposal instructions for Herpesan (likely Acyclovir) are based on regulatory labeling to maintain product stability and ensure environmental safety.

Area	Regulatory Requirement
Storage Conditions	Store the product in a cool, dry area, typically at room temperature. The container must be kept tightly closed and protected from light and moisture to prevent degradation. Avoid exposure to excessive heat or freezing, as well as incompatible strong chemicals.
Handling & Safety	The product must be kept out of the reach of children. Avoid breathing any dust and forming particulates when handling.
Disposal Instructions	Unused or expired Herpesan must not be flushed down a toilet or thrown in the household trash. Disposal must occur through an authorized pharmaceutical or special waste collection point according to local and national regulatory legislation, preventing environmental release.