Цикловакс

Quick links to important sections

Цикловакс

Medically reviewed

Rosario Oropesa

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 Цикловакс

Цикловакс is a specialized, prescription-only antiviral medication defined by its active ingredient, Aciclovir (Acyclovir). The drug's active substance is recognized for its essential role in managing infections caused by the herpesvirus family.


Quick Facts

Property Description
Active Ingredient Aciclovir (Acyclovir)
Form Tablet, capsule, cream, solution (IV)
Pharmacological Class Antiviral Agent (Synthetic Nucleoside Analogue)
General Purpose To limit the growth of specific viral infections
Origin Synthetic organic compound

What Type of Medicine is Цикловакс?

Цикловакс is classified as an antiviral agent, belonging specifically to the chemical category of synthetic nucleoside analogues. The active substance, Aciclovir, is a purine nucleoside analogue that structurally mimics guanine. This classification reflects the drug's specialized role in medicine: it is a potent, targeted therapy designed to combat infections caused by specific pathogens, primarily the herpes simplex virus and the varicella zoster virus. This focus differentiates it from general antibiotics, as its mechanism is strictly confined to disrupting viral replication.


Composition and Available Forms

Aciclovir is a synthetic organic compound and the sole active component, making Цикловакс a single active ingredient product (monotherapy). The medicine is supplied in various pharmaceutical preparations to enable different routes of administration, including oral forms like tablets and oral suspension, topical forms such as a cream/ointment for localized use, and a solution for parenteral delivery via intravenous infusion.


General Purpose of an Antiviral Nucleoside Analogue

The general purpose of Цикловакс is to limit the growth, spread, and severity of infections caused by the targeted viruses, which is often observed in the management of recurrent cold sores. Its physiological action is achieved through a mechanism of selective viral deception: the inactive drug is specifically converted to its active form by a virus-specific enzyme. This active form then causes DNA chain termination, effectively sabotaging the virus's ability to replicate. By stopping the production of new viral particles, this targeted mechanism helps the immune system gain control over the viral outbreak.

Regulatory References

  1. Aciclovir on WHO Essential Medicines List
  2. Acyclovir: MedlinePlus Drug Information

What side effects are possible with Цикловакс?

Possible side effects and safety information

The safety profile of Цикловакс (Aciclovir) is formally classified in regulatory documents based on the frequency and the affected body system, ensuring a neutral assessment of potential risks.

Documented Adverse Reactions by Frequency

Adverse effects are categorized based on clinical data, with the majority falling into the Common classification (affecting up to 1 in 10 people). These typically involve headache, dizziness, nausea, vomiting, diarrhoea, abdominal pain, and certain rashes.

Frequency Classification Examples of Documented Reactions
Uncommon Urticaria (hives), accelerated diffuse hair loss (relationship uncertain).
Rare Anaphylaxis, angioedema, reversible increases in bilirubin and liver-related enzymes, increases in blood urea and creatinine.
Very Rare Anaemia, leukopenia, thrombocytopenia, acute renal failure, and severe neurological reactions (e.g., confusion, convulsions, hallucinations).

Key Safety Characteristics and Restrictions

Side effects are formally grouped by System-Organ Classes, including the Nervous system, Gastrointestinal tract, Skin, and Renal and urinary system.

The regulatory profile highlights that certain severe events, such as acute renal failure or severe neurological reactions, though Very Rare, are explicitly documented. These neurological effects are noted as being generally reversible upon treatment cessation.

Population-Specific Safety Notes: Official labeling notes an increased risk of neurological adverse effects in older adults and patients with impaired kidney function. Furthermore, regulatory documentation includes the high-level requirement to maintain adequate hydration during treatment, particularly with high-dose oral or intravenous use, to help reduce the risk of renal issues.

Overdose and Emergency Response

The official regulatory documents define the overdose profile of Цикловакс (Aciclovir) primarily by its effects on the Central Nervous System (CNS) and the renal system.

Officially Documented Overdose Presentations

Overdose may present with serious neurological signs, including agitation, confusion, lethargy, seizures, and, in severe cases, coma. Gastrointestinal effects such as nausea and vomiting have also been documented. The renal system is particularly vulnerable, especially following high intravenous doses, with the documented risk of acute renal failure related to the precipitation of Aciclovir crystals in the kidney tubules. Increased risk for toxicity and adverse neurological effects is noted in elderly patients and individuals with pre-existing renal impairment.

Emergency Actions and Management

Official guidance strictly mandates seeking immediate medical attention for suspected overdose. Furthermore, if a person has collapsed, is having a seizure, has trouble breathing, or cannot be awakened, emergency services must be called immediately. Management for overdose involves providing symptomatic and supportive care. Regulatory information confirms that haemodialysis is a procedure that significantly aids in the removal of the substance from the blood, especially in severe cases, as no specific antidote is known.

Therapeutic Uses of Цикловакс

What Цикловакс treats: Main Uses and Benefits

Цикловакс (Aciclovir) is relevant across domains where additional symptomatic support is needed, primarily addressing infections caused by the Herpesvirus family (HSV and VZV). The medication is typically utilized in conditions characterized by periods of heightened symptoms stemming from these viral sources.

It is commonly used to address the active, symptomatic episodes of herpes labialis (cold sores), genital herpes, and shingles (Herpes Zoster). It is also applied in clinical settings that involve acute or unstable symptom patterns in immunocompromised patients or for severe systemic infections. This use helps address symptom clusters that may become intense, such as the associated pain, burning, and itching, assisting with maintaining functional stability.

Beyond treating acute flare-ups, its application in a preventative capacity (suppressive therapy) is common in situations involving recurrent or episodic manifestations. This provides support that helps ease the overall symptom burden over time and may assist with reducing the frequency of recurrence.


Quick Fact: Relief for Acute Discomfort

Symptom Domain General Therapeutic Benefit
Acute Lesions & Pain Supports the process of lesion healing; assists with maintaining functional stability.
Recurrent Episodes May assist with reducing the frequency of recurrence; contributes to general well-being.

Regulatory References

  1. NIH DailyMed Labeling Information on Acyclovir

Eligibility and Restrictions for Use

The official regulatory eligibility profile for Цикловакс (Aciclovir) is defined by a set of mandatory exclusions and conditional-use criteria across specific patient populations.

Eligibility scope

Category Official Regulatory Statement
Populations for whom use is contraindicated Patients with a demonstrated clinically significant hypersensitivity reaction to aciclovir, valaciclovir, or any component of the specific formulation.
Condition-specific eligibility rules Use in patients with renal impairment requires dosage adjustment, as the total body clearance of aciclovir is dependent on kidney function.
Age-related eligibility rules Elderly patients are more likely to have reduced renal function, meaning the need for dose reduction must be considered in this group. Adults and children are generally eligible for use.
Pregnancy and lactation eligibility status Use during pregnancy is permitted only when the potential benefit justifies the potential risk. Caution is advised when administering to a nursing woman because aciclovir is detected in breast milk.
Eligibility-related restrictions Dehydrated patients and those with underlying neurological abnormalities should use the medicine with caution and require close monitoring.

Connection to the overall eligibility profile

Official documents define eligibility by establishing absolute contraindications based on hypersensitivity, thereby prohibiting use in a specific group. For eligible populations, the profile imposes conditional use criteria, specifically regulating the use based on the patient's renal status and ensuring a documented benefit-risk assessment for pregnant patients, as mandated by regulatory bodies.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Цикловакс (Acyclovir) is primarily eliminated from the body by the kidneys, and its interaction profile centers on drugs that can affect its renal clearance or increase the risk of kidney damage.

Pharmacokinetic Interactions

Interacting Product Category Specific Medicine(s) Mechanism of Interaction (Regulatory Basis)
Agents Affecting Tubular Secretion Probenecid, Cimetidine Probenecid significantly increases Acyclovir plasma concentrations and half-life by competitively inhibiting its active renal tubular secretion, thereby reducing its urinary excretion.
Nephrotoxic Agents Amphotericin B, Cisplatin, Cyclosporine, Methotrexate, Tacrolimus, certain antibiotics (e.g., aminoglycosides) Coadministration with drugs known to impair kidney function (nephrotoxic agents) increases the potential for Acyclovir-induced renal toxicity.

Clinical and Population-Specific Notes

Concurrent use with probenecid is considered a clinically significant interaction due to the resulting higher exposure to Acyclovir, which increases the potential for adverse effects such as neurotoxicity. Dosage adjustments for Acyclovir are often necessary when coadministered with probenecid, particularly in patients with pre-existing renal impairment.

Patients, especially geriatric patients, who naturally have reduced renal function, should be monitored closely when receiving Acyclovir with any interacting medicine, as higher blood concentrations of the drug can occur. Adequate hydration is important during treatment to mitigate the risk of renal injury.

Mechanism of Action

Enzyme-Driven Selective Activation

Цикловакс operates as an inactive prodrug that undergoes mandatory initial phosphorylation primarily via Viral Thymidine Kinase (TK), an enzyme expressed by the virus within infected cells. This reliance on the pathogen’s specific enzymatic machinery ensures that the drug is activated selectively, resulting in reduced affinity for host cell DNA Polymerase.

Molecular Mechanism of Replication Arrest

The fully phosphorylated drug structurally mimics a natural DNA building block, acting as an obligate chain terminator when incorporated into the growing viral DNA strand due to the lack of a hydroxyl group. It concurrently functions as a competitive inhibitor of Viral DNA Polymerase. This definitive blockade leads to the cessation of viral genome replication, which is the core physiological step that suppresses viral particle production and subsequent propagation in tissues.

️ Mechanistic Constraints and Pathogen Evasion

The mechanism's functional activity is constrained when the virus is in a latent (dormant) state, characterized by the absence of viral enzyme expression. Furthermore, the action can be circumvented by mutations in the genes for Thymidine Kinase or DNA Polymerase, which weaken the drug's affinity or block its activation pathway.

Dosage and Administration Information

Цикловакс (Aciclovir) is administered according to strict, labeled instructions that define the route, dose, frequency, and duration of use. The medicine is available for oral administration (tablets, capsules, suspension), topical application (cream/ointment), and intravenous (IV) infusion for systemic use.

Dosing and Administration Patterns

Official oral dosing regimens vary substantially based on the context of use. For acute treatment, the dosage typically involves 200 mg or 800 mg per dose. The standard frequency for acute oral therapy is five times daily, which requires four-hour spacing between doses while omitting the night dose. For suppressive use aimed at recurrence management, the dose is generally 400 mg twice daily.

Treatment duration is set by official guidelines: acute courses typically run for 5 to 10 days. Conversely, suppressive courses may extend for up to 12 months, after which therapy should be interrupted for patient reassessment.

Procedural Conditions and Adjustments

Oral forms may be taken with or without food. However, all forms require procedural adherence, such as ensuring that the IV solution is administered as a slow, controlled infusion over a period of at least one hour. Furthermore, standard medical guidelines specify dose adjustments for patients with renal impairment, with modifications based on laboratory measurement of creatinine clearance.

Recent Clinical Evidence

Research evidence / Overview of studies for Цикловакс (Aciclovir)


Evidence for Use in Recurrent Genital Herpes

This section will summarize the available evidence base for the use of Цикловакс in managing recurrent genital herpes, describing the high-quality randomized controlled trials (RCTs) that explored outcomes related to the frequency of outbreaks and examining the duration of active episodes.

RCTs examined the drug's profile in conditions characterized by fluctuating manifestations, focusing primarily on immunocompetent adults experiencing frequent recurrences. Findings describe measurements related to the count of recurrent episodes during the study, reporting patterns observed in the studied groups over defined time intervals (up to 12 months) when the drug was observed in a continuous, suppressive regimen. Research highlights how outcomes evolved in the observed populations, where studies monitored the time required for lesions to heal.

What remains uncertain is the long-term effects beyond one year of continuous use, as follow-up durations were limited in the primary research. The research provides limited insight into how outcomes related to asymptomatic viral shedding were observed in research, and data for certain groups, such as children and adolescents, remain limited.


Evidence for Use in Herpes Zoster (Shingles)

This part of the overview will focus on the studies, including double-blind, placebo-controlled trials, that examined the drug's profile for shingles and tracked outcomes such as the time required for rash healing and the severity of associated acute pain.

High-quality randomized, placebo-controlled trials monitored outcomes related to physical discomfort. Research describes how symptoms evolved in the observed populations, reporting measurements related to the time required for rash healing when the drug was studied for acute episodes. Findings also describe patterns observed in the studies related to the severity and duration of outcomes related to physical discomfort. However, evidence suggests that the findings were mixed regarding outcomes linked to the duration of long-term pain, known as postherpetic neuralgia (PHN).


What is Still Uncertain About Цикловакс

Across all indications, data are still emerging regarding the full spectrum of long-term effects, as follow-up durations were limited in the primary research. The consistent patterns related to complex long-term sequelae, such as the study outcomes for postherpetic neuralgia, were mixed across the studies examined. Comparative evidence is lacking for certain conditions, particularly in head-to-head trials against newer antivirals, and subgroup findings are uncertain for vulnerable populations. The evidence highlights what is known—and what is still uncertain—particularly concerning continuous use and rare complications.

Key Studies & References

  1. Acyclovir drug labeling and package insert information (DailyMed)
  2. WHO Model List of Essential Medicines
  3. NIH National Library of Medicine (NCBI) database searches (for RCTs and systematic reviews on HSV/VZV)
  4. StatPearls: Acyclovir (referencing severe systemic infections like HSV Encephalitis)

Frequently Asked Questions (FAQ)

Common questions about Цикловакс (FAQ)


Q: Как скоро обычно начинает действовать Цикловакс?

Studies and official information indicate that initial effects, such as the reduction of symptoms, may begin within 24–48 hours of starting treatment. Studies note that effectiveness in reducing symptoms is often observed when treatment is initiated early. Clinical trials track complete healing over a full course of treatment, which may take several days.


Q: Если пропустить прием, что делать?

Official patient administration instructions state that if a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the regulatory instruction indicates the missed dose is omitted. Official guidelines state that taking two doses at the same time to compensate for a missed one is not recommended.


Q: Через сколько времени можно ожидать улучшения?

Improvements in symptoms are generally expected to begin within the first one to two days after starting the medication. The overall progression of the condition toward healing is monitored throughout the full prescribed course. Official information supports the importance of adherence to the administration schedule.


Q: Есть ли риск набора веса при приеме Цикловакс?

Weight gain is not formally listed as a common, uncommon, rare, or very rare adverse reaction in the official regulatory documents describing the safety profile of this medicine. The side effect profile focuses on other common and rare documented reactions.


Q: Можно ли пить кофе, когда принимаешь Цикловакс?

Official documents do not specify restrictions on consuming coffee or other routine beverages. The oral forms of the medicine may be taken with or without food. Specific interactions involving coffee or other routine beverages are not described in the regulatory information.


Q: Есть ли ограничения по еде или напиткам при приеме?

The oral forms of the medicine may be taken with or without food. The official regulatory profile includes the specific requirement to maintain adequate hydration (drinking plenty of fluids) during treatment, particularly with high-dose use, as it helps reduce the risk of potential renal issues.


Q: Может ли Цикловакс взаимодействовать с травами или добавками?

Scientific data regarding the interaction between this medicine and specific herbal remedies, supplements, or vitamins are often limited or unavailable in official sources. Healthcare professionals rely on a complete list of all products being used to conduct a thorough assessment.


Q: Чем Цикловакс отличается от других похожих лекарств?

Цикловакс is classified as a synthetic nucleoside analogue antiviral agent. Its distinguishing characteristic is its selective mechanism: it requires mandatory activation by a virus-specific enzyme and works by causing DNA chain termination. This mechanism strictly targets viral replication, differentiating it from general antibiotics.


Q: Почему некоторые люди говорят, что Цикловакс 'не помогает'?

Official documents describe that the drug’s function is constrained when the virus is in a latent (inactive or dormant) state, which prevents the drug's activation. Effectiveness can also be weakened by certain mutations that may occur in the viral enzymes (Thymidine Kinase or DNA Polymerase).


Q: Какова длительность курса лечения Цикловакс?

The official duration of use varies substantially based on the purpose of the treatment. Acute treatment typically involves 5 to 10 days of therapy. Conversely, suppressive use aimed at managing recurrence may be planned for up to 12 months, followed by necessary patient reassessment.


Q: Может ли внезапная отмена Цикловакс вызвать проблемы?

For long-term suppressive use, official guidelines state that therapy should be interrupted after a set period (such as 12 months) for a thorough patient reassessment. This interruption is a planned process overseen by a healthcare professional and is part of the standard management.


Q: Как долго Цикловакс остается в организме?

The medicine is primarily eliminated from the body by the kidneys. Pharmacokinetic data indicates that for individuals with normal kidney function, the half-life (the time required for the amount of drug in the bloodstream to be reduced by half) is approximately 2.5 to 3.3 hours. This means the active substance is generally cleared from the bloodstream within one day.


Q: Правда ли, что Цикловакс может изменить настроение?

The regulatory profile documents very rare but severe neurological reactions, including confusion and hallucinations, which are noted as generally reversible upon treatment cessation. Changes in mood or behavior are linked to these documented neurological effects. The occurrence of these neurological effects requires close management by a healthcare professional.


Q: Можно ли принимать Цикловакс вместе с витамином D?

Scientific data on the interaction between this medicine and specific vitamins or supplements are often limited or unavailable in official sources. Healthcare professionals rely on a complete list of all products being used to conduct a thorough assessment.


Q: Есть ли данные о долгосрочном использовании Цикловакс?

Regulatory documentation indicates that data are still emerging regarding the full spectrum of effects from long-term, continuous use. Regulatory documents indicate that follow-up durations in the primary research were often limited to approximately one year of continuous use.


Q: Влияет ли Цикловакс на способность концентрироваться?

Common side effects such as dizziness are documented in the safety profile. Very rare neurological reactions, including confusion, are also noted. It is noted that these documented effects may impact concentration, alertness, or ability to focus.


Q: Можно ли принимать Цикловакс при наличии аутоиммунных заболеваний?

Official eligibility criteria do not list autoimmune diseases as an absolute contraindication, meaning use is not strictly prohibited. However, the use of this medicine requires careful monitoring and conditional assessment for all patients considered vulnerable or high-risk.


Q: Нужно ли менять образ жизни при приеме Цикловакс?

The official regulatory profile includes the specific requirement to maintain adequate hydration (drinking plenty of fluids) during treatment. This is especially important with high-dose oral or intravenous use, as it helps reduce the risk of potential renal issues.


Q: Может ли прием Цикловакс вызвать сонливость?

The regulatory profile documents common side effects, such as dizziness. Rare and very rare central nervous system effects are also documented and may be associated with feelings of lethargy, drowsiness, or altered awareness.


Q: Как Цикловакс связан с иммунной системой?

The medicine is classified as an antiviral agent, and its physiological action is strictly focused on disrupting viral replication. By stopping the production of new viral particles, this targeted mechanism helps the body's immune system gain control over the viral outbreak.


Q: Можно ли найти Цикловакс без рецепта?

Systemic forms of the medicine, such as tablets, capsules, and IV solutions, are generally classified as prescription-only medicines. Topical formulations, such as the cream or ointment used for localized application, may be available for purchase without a prescription.


Q: Почему Цикловакс иногда называют 'поддерживающим' средством?

The medicine is sometimes described in this way because it is officially used for long-term suppressive courses. This is a form of ongoing, planned use, often lasting up to 12 months, aimed at managing the recurrence of certain viral episodes.


Q: Можно ли водить машину после приема Цикловакс?

Official documents state that the patient's overall state of health and the risk of adverse effects, such as dizziness or neurological reactions, should be carefully considered. The effect of the medicine on the ability to drive or use machinery has not been specifically studied.


Q: Как часто нужно сдавать анализы при приеме Цикловакс?

Official documents mandate that dose adjustments must be made based on laboratory measurements (creatinine clearance) for patients with renal impairment. The frequency of any required laboratory monitoring for this medicine is determined by a healthcare professional based on the individual patient's condition.


Q: Влияет ли Цикловакс на результаты анализов крови?

The regulatory safety profile documents rare and very rare events that may affect laboratory values. These include reversible increases in blood urea, creatinine, bilirubin, and liver-related enzymes. Very rare changes such as anemia, leukopenia, and thrombocytopenia are also noted.


Q: Может ли Цикловакс повлиять на менструальный цикл?

Regulatory documentation on adverse effects includes reports of menstrual abnormalities. It is important to note that the frequency of this event is generally not categorized as common.


Q: Взаимодействует ли Цикловакс с алкоголем?

Official documents do not include a specific contraindication or warning against the consumption of alcohol while using this medicine. No explicit interaction with alcohol is listed in the regulatory profile.


Q: Влияет ли Цикловакс на артериальное давление?

Low blood pressure (hypotension) is documented as a possible side effect in the regulatory safety profile of the medicine. This is a potential adverse event that is noted in official documents.


How should Цикловакс be stored and disposed of?

How to Store and Dispose of Цикловакс?

Цикловакс must be stored carefully to maintain its effectiveness and stability. Keep the product refrigerated at a temperature between 2 C and 8 C (36 F and 46 F). It is essential to not freeze the product; any vials or syringes that have been frozen must be immediately discarded. Store the container in the original outer carton to protect it from light. Do not shake the product vigorously.

Keep Цикловакс out of the reach of children. The proper disposal of unused medication and packaging should be carried out in accordance with all applicable federal, state, and local regulations. Do not use the product past the expiration date printed on the packaging.

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

Available in countries:

Equivalent of Цикловакс found in:

A-Z Index: