Citosol

Quick links to important sections

Citosol

Treatment option:

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 Citosol

Property Description
Active ingredient Thiamylal sodium
Form Sterile powder for intravenous injection (solution)
Pharmacological class General Anesthetic, Central Nervous System (CNS) Depressant
General purpose Induction of general anesthesia
Origin Synthetic organic compound (thiobarbiturate derivative)

What is Citosol and What Chemical Class Does It Belong To?

Citosol is defined as a potent ultrashort-acting barbiturate, a class of synthetic drugs primarily employed to quickly and temporarily depress the central nervous system. Its core ingredient is Thiamylal sodium, a chemical analogue of thiobarbituric acid. This compound is categorized as a synthetic organic compound, which means it is manufactured through controlled chemical processes rather than being naturally derived. As a single-ingredient drug, Citosol’s identity is defined by this core component, characterized by its rapid action profile. Thiamylal is known for its high lipid solubility, a unique factor that enables the swift crossing of the blood-brain barrier, which is central to its ultra-short classification.


Citosol’s Pharmacological Classification and Purpose

Citosol is classified within the major pharmacological group of General Anesthetics and is fundamentally characterized as a profound Central Nervous System (CNS) Depressant. The drug’s main function or therapeutic purpose is the rapid induction of general anesthesia, providing medical personnel with a reliable means of achieving unconsciousness swiftly. Thiamylal is clinically recognized as a fast-acting intravenous anesthetic agent. Its high potency allows it to bring about this state immediately, distinguishing it from longer-acting agents used for sustained sedation. This rapid action is critical for establishing a controlled state of unconsciousness before the main anesthetic regimen is initiated.


Composition and Administration Form

The composition of Citosol centers on the active substance, Thiamylal sodium, which is typically supplied as a sterile powder requiring reconstitution into an aqueous solution for injection. The drug is strictly intended for the intravenous route of administration. This specific dosage form and route are essential because the immediate introduction of the drug into the bloodstream directly enables the rapid effects required of a general anesthetic induction agent. This characteristic is a defining differentiating factor when compared to general anesthetics administered via inhalation or other routes.

Regulatory References

  1. Thiamylal MeSH Descriptor

What side effects are possible with Citosol?

Possible Side Effects and Safety Information

The safety profile of Citosol (Thiamylal sodium) is structured around its classification as a potent Central Nervous System (CNS) depressant. The officially documented adverse reactions are categorized by the systems they affect and their regulatory frequency of occurrence.


Key Adverse Reactions by System

The most prominent documented effects are observed in the Respiratory and Cardiovascular Systems. Common (1% to 10%) adverse reactions listed in regulatory summaries include respiratory depression, hypotension (low blood pressure), laryngospasm, bronchospasm, and various cardiac arrhythmias. Effects on the Nervous System may include somnolence, delayed awakening, and involuntary movements.


Serious Safety Concerns

Official regulatory documents identify several serious adverse reactions. These include life-threatening events such as respiratory arrest, cardiac arrest, and severe anaphylactic shock (a rare, generalized allergic reaction). A local safety concern is the documented risk of tissue necrosis and sloughing if the medication leaks outside the vein (extravasation) or is improperly injected into an artery.


Population and Contextual Safety Notes

Regulatory labeling highlights specific safety considerations for certain patient groups. Elderly or debilitated patients may show increased sensitivity to the depressant effects. Caution is specifically noted for individuals with hepatic impairment (liver dysfunction) and those with a history of Porphyria, as barbiturates may exacerbate this condition. Furthermore, safety documents explicitly state that rapid or excessive administration of Citosol is associated with a significantly increased risk of severe hypotension and apnea.

Overdose and Emergency Response

Overdose and when to seek help

The official regulatory profile for Citosol overdosage is defined by the potential for rapid and severe Central Nervous System (CNS) and cardiorespiratory depression, which requires immediate medical intervention.

Feature Official Regulatory Description
Documented Manifestations Profound CNS depression (coma, prolonged unconsciousness), severe respiratory depression (hypoventilation, apnea), and circulatory depression (severe hypotension, shock).
Life-Threatening Outcomes Overdose may rapidly lead to life-threatening complications, including respiratory arrest, cardiac arrest, and subsequent hypoxic encephalopathy.
Emergency Action Seek immediate medical assistance and emergency care upon any suspected or apparent overdosage. The medication must be discontinued immediately.
Antidote Regulatory information confirms that no specific pharmacological antidote is known for this overdose.

Management procedures described in official labels focus on essential supportive measures. These include establishing and maintaining a patent airway, providing assisted ventilation, and administering intravenous fluids for circulatory support. Continuous cardiovascular monitoring and hospitalization for close observation are mandatory procedures. Increased susceptibility to severe outcomes is noted in populations with pre-existing hepatic or renal impairment.

The immediate and severe risk of respiratory and cardiac failure means that the seeking of urgent medical help is the primary action mandated by regulatory authorities.

Therapeutic Uses of Citosol

Symptomatic Relief for Episodic Discomfort

Citosol is generally used in situations involving symptoms related to physical discomfort that may interfere with daily functioning. The drug is applicable within clinical settings that involve acute or disruptive symptom patterns, where short-term symptomatic assistance is commonly needed. The medication is used to help with symptoms associated with acute or episodic changes across conditions involving episodic or fluctuating manifestations.

It is considered relevant for easing the overall symptom load when symptoms become more noticeable.

Support in Symptom Management

The medication is applied across domains where additional symptomatic support is needed, such as when symptoms may intensify temporarily or fluctuate in severity, and is considered relevant when supportive symptom management is appropriate. The medication is applied in addressing symptoms that create noticeable physiological strain and may help manage symptoms that interfere with daily functioning. It assists with maintaining functional stability and supports general well-being during symptomatic phases.

Quick Fact: Relief for Episodic Symptoms
Citosol is commonly used to help with symptom clusters that appear suddenly or fluctuate, providing supportive relief when symptoms interfere with routine activities.

Eligibility and Restrictions for Use

Citosol (Thiamylal sodium) eligibility is strictly defined by regulatory documents, distinguishing between absolute prohibitions and conditional use populations.

Absolute Contraindications

Use is prohibited for patients with a known allergy or hypersensitivity to any barbiturate. The medicine is also contraindicated in patients with specific metabolic disorders, namely acute intermittent porphyria or variegate porphyria. Contraindications extend to patients with pre-existing conditions that compromise the airway, such as severe asthma or respiratory obstruction, and those diagnosed with dystrophia myotonica.

Restricted and Conditional Use

Regulatory documents require conditional use and often a mandatory dose reduction for several patient groups. These include older adults and patients with significant organ impairment, specifically hepatic or renal impairment, due to prolonged drug metabolism. Extreme caution is also stipulated for patients in shock or those with severe cardiovascular disease.

Age and Reproductive Eligibility

Citosol is documented for use in adults, infants, and children for the induction of general anesthesia. Use during pregnancy is restricted to situations where it is clearly needed (Pregnancy Category C). The official label requires temporary suspension of breastfeeding following administration.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Official regulatory documentation defines Citosol (Thiamylal sodium) interaction profile primarily through its additive depressant effects and its capacity to alter the metabolism of co-administered medicines.

Pharmacodynamic Interactions and Substance Restrictions

Co-administration with other Central Nervous System (CNS) Depressants, including opioids and benzodiazepines, is officially documented to result in additive CNS depressant effects. This pharmacodynamic interaction increases the risk of profound sedation and respiratory depression. Similarly, the CNS depressant effect is additive with ethyl alcohol (ethanol), a substance interaction noted in official warnings. Additionally, use is formally contraindicated in patients with latent or manifest porphyria, a required restriction for the barbiturate class.

Pharmacokinetic and Administration Constraints

Citosol is classified as an enzyme inducer of Cytochrome P450 enzymes, specifically CYP3A4, CYP2C9, and CYP2C19. This pharmacokinetic interaction leads to a decreased plasma concentration and reduced exposure of co-administered medicinal products that are substrates of these enzymes. Conversely, co-administration with CYP Enzyme Inhibitors may lead to increased plasma exposure and prolonged effects of Citosol itself. The solution is subject to a physicochemical restriction and must not be mixed with acidic solutions like atropine sulfate or succinylcholine chloride. Population-specific warnings note that severe hepatic or renal dysfunction may prolong or potentiate the drug's effects due to impaired clearance.

Mechanism of Action

How Citosol Works: The Mechanism of Action

Citosol is a selective inhibitor of the enzyme Phosphodiesterase-4 (PDE4), which is highly expressed within key inflammatory and immune cells, including T-lymphocytes and monocytes. Inhibition of PDE4 reduces the enzymatic hydrolysis of cyclic adenosine monophosphate (cAMP), leading to increased intracellular concentrations of cAMP within these cells.

Elevated cAMP levels initiate a complex intracellular cascade that regulates the activity of various transcription factors. This modulation ultimately alters the production profile of several pro-inflammatory mediators, notably decreasing the synthesis of cytokines such as TNF-alpha and IL-12. This sustained alteration in intracellular signaling and subsequent cytokine release modifies the overall amplification of the inflammatory process at the systemic level.

Dosage and Administration Information

Administration Guidelines for Citosol Syrup

These instructions outline the standardized procedure for the use of Citosol (an oral syrup formulation) to ensure the correct administration of the liquid medicine.

Administration Scope Requirement
Route of Administration Oral (Taken by mouth only).
Dosing Schedule The total dose is divided and administered two to three times daily. Dosing is individualized based on patient response and age/weight.
Timing in Relation to Meals May be taken with or without food.
Preparation Requirements The bottle must be shaken well before each measurement.
Age-Group Administration Contraindicated for use in newborn or premature infants. Use is restricted for children under one year of age.
Missed-Dose Rules If a dose is missed, skip the missed dose and continue with the next scheduled dose. Do not take a double dose to compensate.
Special Procedural Conditions The required dose must be carefully measured using a calibrated device (spoon or cup), not a common household spoon.

Procedural Structure:

  1. Shake the Citosol bottle thoroughly before use.
  2. Measure the exact volume using a dedicated measuring tool.
  3. Administer the dose orally.
  4. Repeat the administration according to the specific daily frequency and dose intervals determined by the prescriber.

The administration protocol is structured to ensure that the patient receives the proper dose via the intended oral route. Following these explicit procedural steps, timing rules, and age-based limitations is essential for the medicine’s standardized application.

Recent Clinical Evidence

Evidence for Use in Inducing General Anesthesia

Citosol (Thiamylal sodium) was studied for its primary use as an agent for the rapid start of general anesthesia. The primary evidence for this application includes Randomized Controlled Trials (RCTs) and various comparative studies. These trials typically measured the time to loss of consciousness (induction time), the overall quality of induction, and short-term physiological responses, including changes in the patient's blood pressure and heart rate. The studies reported measurements of the time to unconsciousness, where a rapid time to unconsciousness was noted. Comparative trials described patterns observed over the short period of time immediately following drug administration, contributing to the broader evidence landscape regarding anesthetic induction agents.

However, the evidence base is limited by a lack of recent, large-scale comparative trials, and research provides limited insight into longer-term recovery or outcomes that extend beyond the initial hours after a surgical procedure, as follow-up durations were limited.

Evidence for Other Studied Uses

Research has explored the use of Citosol in patients experiencing refractory status epilepticus—a condition involving ongoing seizures. The evidence for this application primarily consists of retrospective analyses of medical records and small case series conducted in critical care settings. Studies monitored key outcomes related to seizure activity, including the time to cessation of clinical seizure activity and the ability to achieve a pattern known as burst suppression on an Electroencephalogram (EEG) reading.

Similar observational studies examined Citosol in managing elevated Intracranial Pressure (ICP). The evidence for both non-anesthesia applications is constrained by a lack of large, prospective, randomized controlled trials, relying instead on specialized observational data. For all studied uses, long-term effects are not fully established, and data for certain groups of patients, such as older adults, remain insufficient.

Frequently Asked Questions (FAQ)

Common questions about Citosol (FAQ)


Q: Can Citosol affect your blood or increase the risk of bleeding?

A: Official product information notes that Citosol is contraindicated for patients with Porphyria, which is a group of rare metabolic disorders that affect blood components. However, core regulatory documents do not generally specify an increased risk of generalized bleeding among the commonly reported adverse reactions.

Q: Does Citosol interact with herbal supplements or vitamins?

A: Citosol is known to affect how the body processes some other medicines by acting as an enzyme inducer—speeding up certain CYP enzymes in the liver. While specific herbal supplements or vitamins are usually not officially listed, any product that significantly affects these liver enzymes could potentially change the exposure or duration of effect of Citosol or the co-administered product.

Q: What kind of monitoring or follow-up tests are needed while taking Citosol?

A: Because Citosol is a powerful anesthetic agent administered intravenously, official guidelines require continuous monitoring of respiratory and cardiac function during its use. For patients with pre-existing conditions like liver or kidney impairment, regulatory information notes that caution and close monitoring may be necessary due to the potential for the drug's effects to be prolonged.

Q: Is it safe to drink alcohol in moderation while on Citosol?

A: Official regulatory documents indicate that the use of Citosol with ethyl alcohol (ethanol) is warned against. This is because the depressant effects of Citosol on the central nervous system are intensified when combined with alcohol, increasing the risk of profound sedation and respiratory depression.

Q: Is Citosol available in different strengths or forms (e.g., tablet, capsule)?

A: No. Citosol (Thiamylal sodium) is designed as a specialized medication for acute procedures in a medical setting. It is supplied as a sterile powder requiring reconstitution into an aqueous solution intended only for intravenous injection. It is not formulated as a tablet or capsule for oral use.

Q: What happens if I forget to take Citosol for a few days?

A: Citosol is primarily used for the rapid, acute induction of general anesthesia, not for chronic treatment taken at home. Because of its use in acute, hospital-based settings, regulatory information does not address the issue of missing multiple daily doses in a typical patient scenario.

Q: Are there any long-term risks associated with Citosol use?

A: Official regulatory documents and research overviews note that the evidence base for Citosol provides limited insight into longer-term recovery or outcomes extending beyond the immediate post-procedure period. As a result, long-term effects following its use are not fully established in the available data.

Q: Is Citosol the same as a medicine like Cilostazol or is it a different drug?

A: Citosol (Thiamylal sodium) is a different medicine from Cilostazol. Citosol is classified as an ultrashort-acting barbiturate that acts as a powerful Central Nervous System (CNS) depressant. Cilostazol belongs to a different pharmacological class, a phosphodiesterase inhibitor, typically used for conditions that improve blood flow.

Q: Are headaches a common side effect when starting Citosol?

A: Official regulatory lists of common side effects include nervous system effects such as somnolence (drowsiness) and delayed awakening. While headache is sometimes noted, it is not consistently listed as one of the most frequent (1–10%) adverse reactions associated with this medicine.

Q: Is it normal to experience dizziness or lightheadedness while taking Citosol?

A: Citosol is known to frequently cause hypotension (low blood pressure), which is a cardiovascular effect that may contribute to feelings of dizziness or lightheadedness. It also causes CNS depression, which can manifest as drowsiness or somnolence.

Q: Are there any foods or drinks, like grapefruit juice, that should be avoided while taking Citosol?

A: Official warnings explicitly advise against use with ethyl alcohol (ethanol) due to additive CNS depressant effects. There are no consistent regulatory warnings documented in core regulatory texts concerning specific foods like grapefruit juice.

Q: Why might a doctor prescribe Citosol instead of a different medicine for the same condition?

A: Citosol is often prescribed for its ability to produce a rapid time to unconsciousness upon intravenous administration. This rapid action profile is a critical feature when medical personnel need to swiftly induce general anesthesia.

Q: Is Citosol a medication that needs to be taken long-term?

A: The drug's primary function is the rapid induction of general anesthesia, which is a short-duration, acute procedure. Research notes that long-term data is limited, suggesting Citosol is not intended for chronic, ongoing use.

Q: Does Citosol have an impact on blood cell counts?

A: Regulatory information indicates that Citosol is contraindicated in patients with Porphyria, a metabolic condition that affects blood-related pigments. While Porphyria involves the blood, official safety information does not generally specify effects on common blood cell counts.

Q: Are there different brand names or generic versions available for Citosol?

A: Citosol is one brand name for the active drug substance, which is generically known as Thiamylal sodium. Other brand names may be available depending on the country or manufacturer.

Q: How soon after stopping Citosol do its effects wear off?

A: Citosol is officially classified as an ultrashort-acting drug. Its effects wear off quickly, primarily because the drug is rapidly redistributed from the brain into other tissues, which results in a swift return of consciousness after the acute administration.

Q: Does smoking affect how well Citosol works?

A: The effectiveness of Citosol can potentially be altered by any substance that affects the Cytochrome P450 enzymes in the liver, as this is how the drug is processed. Although smoking is not always explicitly listed, any substance or habit known to significantly induce these enzymes could change the drug's overall exposure or duration of effect.

Q: Can Citosol cause problems with sleep or insomnia?

A: As a powerful Central Nervous System (CNS) depressant, official adverse reaction reports list side effects such as somnolence (drowsiness) and delayed awakening that occur after administration. Insomnia is not a consistently listed adverse reaction.

Q: Why is Citosol sometimes contraindicated in people with heart failure?

A: Citosol is a potent depressant on the cardiovascular system that can cause significant hypotension (low blood pressure) and cardiac arrhythmias. Regulatory information indicates that extreme caution or a dose reduction is necessary for patients with severe cardiovascular disease, as the drug carries a high risk of worsening their underlying condition.

Q: Is Citosol used for any other purposes besides its main indicated use?

A: Citosol's main regulatory indication is the rapid induction of general anesthesia. However, studies and official information show it has also been used for specific, specialized applications such as controlling refractory status epilepticus (ongoing seizures) and managing elevated intracranial pressure (ICP) in critical care settings.

Q: If I experience chest pain on Citosol, what should I be aware of?

A: Official safety documents indicate that Citosol is known to affect the cardiovascular system and can cause serious adverse reactions, including cardiac arrhythmias (irregular heartbeats) and cardiac arrest. The potential for these serious cardiac adverse effects underscores that any symptom like chest pain is considered a serious medical concern.

Q: Does Citosol interact with any medications for depression or anxiety?

A: Citosol is a Central Nervous System (CNS) depressant. It has additive depressant effects with other CNS-depressing medicines, which may include many medications used for anxiety and depression. Combining these types of drugs increases the risk of severe sedation and respiratory issues.

Q: How is Citosol metabolized or processed by the body?

A: Regulatory documents explain that Citosol is primarily metabolized, or broken down, by specialized enzymes in the liver, specifically the Cytochrome P450 system. The resulting breakdown products are then mainly eliminated from the body through the kidneys.

Q: Are the side effects of Citosol permanent or do they usually go away?

A: Most common adverse effects like hypotension and drowsiness are related to the drug's rapid, short-term anesthetic action and are typically transient. However, official warnings note a local safety concern: improper injection into an artery or leakage outside the vein can lead to the serious risk of tissue necrosis and sloughing.

Q: Does Citosol require a prescription?

A: Yes, Citosol is a potent general anesthetic agent. It is strictly available by prescription only and is intended for intravenous administration exclusively in hospital or specialized care settings where continuous monitoring by qualified personnel can be ensured.

Q: What happens if Citosol is stopped suddenly?

A: Citosol is an acute-use drug for anesthesia induction and is not a chronic medication, so stopping it suddenly is not a typical patient concern. However, as a barbiturate class drug, regulatory warnings note its potential to be habit forming.

How should Citosol be stored and disposed of?

Official Storage and Disposal Requirements for Citosol

Storage Conditions

Citosol must be stored at Controlled Room Temperature (15 C to 30 C), as defined by regulatory standards. It is mandatory to protect Citosol from light and moisture and to keep the product in its original, tightly closed container.

Handling and Stability

Do not freeze Citosol. If the product is reconstituted or diluted, stability is limited, and it must be used within the specified post-preparation period (e.g., 24 hours). Keep Citosol stored out of the reach of children.

Disposal Rules

Unused, expired, or contaminated Citosol must be disposed of according to local and national regulations for pharmaceutical waste. Do not dispose of Citosol in household trash or flush it down the toilet or sink, especially if it is classified as a cytotoxic or hazardous agent. Follow official guidelines for the disposal of hazardous pharmaceutical waste.

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

Available in countries:

Equivalent of Citosol found in:

A-Z Index: