Isoflo

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Isoflo

Treatment option: Anesthesia, General Anesthesia

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 Isoflo

What is Isoflo? (Isoflurane)

This section defines the core identity and general purpose of the medicine Isoflo, which contains the active ingredient Isoflurane, a synthetic compound used in controlled medical settings.

Property Description
Active Ingredient Isoflurane (INN)
Form Volatile liquid for vaporization
Pharmacological Class General anesthetic (Inhalational)
Common Use Induction and maintenance of general anesthesia
Origin Synthetic compound (Halogenated ether)

What Type of Medicine is Isoflo? (Definition and Classification)

Isoflo is a brand of prescription-only medicine whose active component is Isoflurane, a synthetic compound classified as an inhalational anesthetic. It belongs to the high-level pharmacological class of general anesthetics, which are chemically categorized as halogenated ethers, defining its primary method of use and chemical structure. The effectiveness of this medicine in achieving deep and stable unconsciousness is characterized by its pharmacological properties. The medicine is indicated for both the induction and maintenance of general anesthesia. As an inhalational agent, it is administered to the body via the respiratory system, offering anesthetists rapid control over the patient's depth of unconsciousness.

Composition and Form: The Volatile Liquid for Inhalation

Isoflo is supplied as a pure volatile liquid which must be converted into a vapor for patient delivery, confirming its required route of administration by inhalation. It is a single-component product comprised solely of Isoflurane, a clear, colorless, stable liquid containing no additives or chemical stabilizers. This formulation, distinguished from intravenous anesthetics, is used primarily in institutional settings. The specialized form of this volatile liquid is integral to its function, enabling its rapid diffusion across the lungs into the bloodstream and, subsequently, the brain. This characteristic facilitates precise control during both the induction and efficient maintenance of general anesthesia.

The General Purpose of an Inhalational Anesthetic

The overarching goal of Isoflurane is to safely facilitate surgical or complex medical procedures by creating a controlled state of central nervous system depression. This action temporarily blocks sensation, movement, and the formation of memory. A typical use scenario involves using Isoflo to maintain a steady level of anesthesia in a patient during a prolonged surgery. The medicine's purpose is limited to establishing this anesthetic state; the controlled, temporary physiological action ensures the patient remains unaware and pain-free for the procedure's duration, upholding the fundamental benefit of general anesthesia.

Regulatory References

  1. Isoflurane FDA Approval - NIH

What side effects are possible with Isoflo?

Possible Side Effects and Safety Information

The safety profile of Isoflo (Isoflurane) is systematically classified by regulatory authorities based on the physiological systems affected and the frequency of occurrence. Documented adverse reactions are grouped into categories such as Cardiovascular, Respiratory, Thoracic and Mediastinal, and Hepatobiliary disorders.


Documented Adverse Reaction Categories

Classification Examples of Documented Reactions
Common (1%) Nausea, Vomiting, Postoperative Shivering, Chills
Dose-Dependent Hypotension, Respiratory Depression (increasing with deeper anesthesia)

Serious Adverse Reactions and Safety Constraints

Official prescribing information highlights specific serious adverse reactions. The most critical include the life-threatening hypermetabolic state Malignant Hyperthermia (MH) and Perioperative Hyperkalemia, which is a severe rise in serum potassium that may lead to cardiac events. Fatal cases of Hepatic Necrosis and Severe Hepatic Failure have also been reported in post-marketing experience with halogenated anesthetics.

Safety notes specify restrictions for certain groups. The medicine is contraindicated in individuals with known or suspected genetic susceptibility to MH and is cautioned in those with a history of severe hepatic dysfunction following previous exposure to halogenated agents. Pediatric patients, especially those with latent neuromuscular disease, are noted to have an increased vulnerability to perioperative hyperkalemia. Furthermore, the label notes a chemical risk: the drug can react with desiccated CO2 absorbents to produce Carbon Monoxide, which may elevate carboxyhemoglobin levels.

Overdose and Emergency Response

Overdose and When to Seek Help: Official Regulatory Information

Excessive inspired concentrations of Isoflo (isoflurane) may result in an overdose state defined by official regulatory bodies. The principal documented manifestations are dose-dependent decreases in blood pressure (hypotension) and profound respiratory depression, potentially leading to hypercapnia and excessively deep levels of anesthesia.

Documented Severe Outcomes

Overdose scenarios and acute exposure are associated with severe, life-threatening outcomes detailed in regulatory labeling. Isoflurane may trigger Malignant Hyperthermia (MH), a hypermetabolic syndrome that requires immediate intervention. Furthermore, Perioperative Hyperkalemia has been reported, especially in pediatric patients, leading to severe cardiac arrhythmias and death. Other severe complications documented include hepatic failure and fatal hepatic necrosis.

Emergency Actions and Required Help

Official documentation mandates specific actions when overdose or excessive anesthetic depth is observed. The inspired concentration of Isoflo must be decreased immediately. Respiration must be monitored closely and supported with artificial ventilation and oxygen enrichment as needed. Urgent medical assistance is required if signs of MH or severe cardiovascular instability are observed. While there is no specific antidote for general overdose, intravenous dantrolene sodium is the mandated treatment for Malignant Hyperthermia.

Therapeutic Uses of Isoflo

What Isoflo Treats: Main Uses and Benefits

Isoflo (Isoflurane) is a specialized medication whose use is applied in clinical settings that involve acute or unstable symptom patterns where the rapid and precise management of key physiological states is critical. Its primary application generally involves producing a deep, temporary state of central nervous system depression. The primary therapeutic application of the medication is general anesthesia.


Management of Consciousness for Surgical Procedures

This therapeutic domain addresses the need to temporarily manage symptoms related to awareness, memory formation, and the sensation of pain during operations. Isoflo is commonly used for both the initiation and maintenance of General Anesthesia in adults and children. The supportive relief helps maintain a sense of stability when symptoms are more noticeable, which assists with maintaining functional stability during procedures.


Sustaining Sedation in Intensive Care

Isoflo is also utilized to provide moderate-to-deep continuous sedation for critically ill patients, particularly those requiring prolonged mechanical ventilation in the Intensive Care Unit (ICU). This application helps address groups of symptoms that may become intense or disruptive, such as agitation and distress. This supportive therapeutic relief helps maintain a sense of stability, supports the patient during difficult episodes, and assists with maintaining functional stability during phases when symptoms become more noticeable.


Supportive Care for Refractory Crises

The medication plays a role in managing conditions characterized by periods of heightened symptoms that have become refractory (unresponsive) to standard pharmacological treatments. This includes the clinical situation of Refractory Status Asthmaticus, where its use helps address severe airway constriction, and certain instances of Super-refractory Status Epilepticus (continuous seizures). In these acute settings, Isoflo may assist with addressing distressing manifestations and contributes to easing the overall symptom load during the acute phase, and is applied when supportive symptom management is appropriate.


Quick Fact: Relief for Unconsciousness
The drug assists with managing symptoms related to awareness and memory formation by supporting a stable, reversible state of deep central nervous system depression.

Regulatory References

  1. NIH DailyMed Label for ISOFLURANE

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Isoflo

The eligibility for Isoflo (Isoflurane) is determined by specific population rules and contraindications documented in regulatory labeling.

Populations for Whom Use is Contraindicated Isoflo is strictly contraindicated for individuals with a known or suspected genetic susceptibility to Malignant Hyperthermia (MH). Use is also prohibited in patients who have a confirmed history of hepatitis or unexplained moderate to severe hepatic dysfunction (such as jaundice or fever) following previous exposure to Isoflurane or other halogenated anesthetic agents.

Age-Group Eligibility The medicine is approved for the maintenance of general anesthesia in adults and pediatric patients, including infants older than one month. However, it is not recommended for the induction of anesthesia in infants and children due to a higher incidence of specific respiratory events. Older adult patients typically require lower concentrations for maintenance.

Conditional Use and Restrictions Specific caution is required for patients with pre-existing conditions. These include individuals with Coronary Artery Disease, increased Intracranial Pressure (ICP), and neuromuscular disorders, where administration requires clinical precautions as outlined in the prescribing information. For pregnancy, use is advised only if the potential benefit justifies the risk, as safety for labor and vaginal delivery is not established. Caution is also advised when administering to a nursing woman.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The regulatory profile for Isoflurane defines specific, documented interactions primarily within the category of pharmacodynamic effects. A critical restriction is the co-administration with Succinylcholine, which is formally recognized in labeling as carrying an increased risk of Malignant Hyperthermia (MH).

The drug markedly potentiates the effect of non-depolarizing muscle relaxants, such as Vecuronium and Rocuronium, a clinically significant interaction that reduces the required dose of the paralytic agent. Furthermore, the co-administration of Opioids/Narcotics or Nitrous oxide (N₂O) officially results in a dose-sparing effect, reducing the required inspired concentration of Isoflurane. Amiodarone is also documented to potentially increase cardiodepressant activities.

Regarding substance interactions, chronic alcohol ingestion is noted to cause cross-tolerance, potentially necessitating a higher concentration of Isoflurane for the desired effect. The label also documents that Isoflurane may increase the hepatotoxic activities of Acetaminophen. For patients with underlying hepatic conditions or those receiving drugs known to cause hepatic dysfunction, caution is warranted concerning repeated administration due to the risk of additive effects. There are no mandatory timing separation rules explicitly documented.

Mechanism of Action

Isoflurane, a halogenated ether, exerts its pharmacological effects through a multifaceted modulation of neural activity, primarily within the Central Nervous System (CNS). Its mechanism involves influencing several key receptor and ion channel systems, which alters the membrane potential of neurons and modifies synaptic transmission.


Amplification of Inhibitory Neurotransmission

Isoflurane acts as a positive allosteric modulator of the gamma-aminobutyric acid ( GABA A) receptor, increasing its sensitivity to GABA. This results in an augmented influx of chloride ions, which hyperpolarizes the neuron, thereby decreasing neuronal excitability. The drug also potentiates inhibitory currents mediated by glycine receptors in the spinal cord.


Suppression of Excitatory Pathways

Isoflurane engages mechanisms that curb excitatory signaling by functioning as an inhibitor of N-methyl-D-aspartate (NMDA) glutamate receptors. By blocking these primary mediators of fast excitatory synaptic transmission, the drug suppresses the flow of excitatory signals, resulting in decreased global electroencephalographic activity.


Modulation of Ion Channels and Systemic Effects

Beyond the main neurotransmitter systems, Isoflurane modulates certain potassium channels, which induces additional neuronal hyperpolarization. Furthermore, the agent causes peripheral vasodilation, leading to a dose-dependent decrease in systemic vascular resistance, which modifies cardiac output.

Dosage and Administration Information

Isoflo (isoflurane, USP) is a volatile liquid inhalation anesthetic and should only be administered by individuals trained in the delivery of general anesthesia and in an adequately equipped setting. The level of anesthesia can be adjusted rapidly due to the drug's properties.

Administration Method

Isoflurane must be administered using a precision vaporizer specifically designed and calibrated for isoflurane to ensure the delivery of a predictable and controlled percentage concentration.

  • Induction: Initial inspired concentrations typically range from 1.5% to 3.0% of isoflurane, combined with oxygen or an oxygen-nitrous oxide mixture, to achieve surgical anesthesia within approximately 7 to 10 minutes.
  • Maintenance: Surgical levels of anesthesia are usually sustained with a lower concentration, typically between 1.0% and 2.5%, often depending on whether nitrous oxide is used concomitantly.

Safety and Monitoring

Continuous, close monitoring of the patient's respiration and hemodynamics (e.g., blood pressure, heart rate) is mandatory throughout the anesthetic procedure, as isoflurane is a profound respiratory depressant and can cause dose-dependent hypotension. Facilities for the maintenance of a patent airway, artificial ventilation, and circulatory resuscitation must be immediately available.

Adequate ventilation and scavenging systems must be used in the operating environment to prevent the accumulation of waste anesthetic gases (WAG). Isoflurane can react with desiccated carbon dioxide absorbents (like soda lime or barium hydroxide lime) to produce carbon monoxide, so absorbents must be checked and replaced if desiccation is suspected. Patients should not undertake hazardous tasks for at least 24 hours post-administration.

Recent Clinical Evidence

Research Evidence / Overview of studies for Isoflo

Evidence for use in General Anesthesia: Induction and Maintenance

The body of research describing Isoflo (Isoflurane) is primarily comprised of a large number of Randomized Controlled Trials (RCTs) and comprehensive Systematic Reviews. Research examined the use of Isoflurane to establish and maintain the reversible state of deep central nervous system depression in research contexts involving fluctuating or unstable symptoms. These research scenarios involved examining the medication against other inhalational agents and intravenous methods of anesthesia.

Study Focus: Time, Emergence, and Recovery

Research was studied for several key temporal outcomes related to the procedure. Trials monitored the time interval needed for a patient to reach the required state of unconsciousness (induction) and the time until the patient awakened after the agent was discontinued (emergence). Studies also monitored outcomes related to systemic or functional imbalance, such as changes in vital signs, during the procedure. The findings describe patterns observed in the studies related to these time points, which help contextualize how patients reported their experience in the immediate post-operative phase.

The evidence level for this core use is generally described as high, supported by regulator-referenced studies. However, research highlights changes measured during the study period, and long-term effects are not fully established. Some older comparative trials may have limitations compared to modern study designs, particularly when exploring outcomes related to specific comparator agents.

Evidence for use in Sustaining Sedation in Intensive Care

Research has explored the use of Isoflo to be evaluated in settings of continuous sedation for critically ill patients who require prolonged support from mechanical ventilation. This research, which includes newer Randomized Controlled Trials and Retrospective Observational Studies, examined temporary physiological imbalance in patients whose conditions involved periods of heightened symptoms, such as agitation and distress.

Studies monitored outcomes reflecting daily functioning or activity level, specifically measuring the time until patients were ready to be removed from the ventilator and the overall length of stay in the Intensive Care Unit (ICU). Findings describe patterns observed in the studies related to these metrics. Data show patterns related to the monitored depth of sedation, which was measured using validated scoring systems.

What is Still Uncertain About Isoflo

Research highlights what is known — and what is still uncertain — about Isoflo. A key limitation is the scarcity of high-level evidence for its use in refractory crises, where data are still emerging and certainty remains low. Furthermore, the overall research provides limited insight into long-term functional outcomes across all indications, as the focus is heavily concentrated on immediate, short-term changes measured during the study period. Comparative evidence is lacking in some contexts, and the research does not determine whether an individual will respond similarly to the patterns observed in group studies.

Key Studies & References

  1. Isoflurane liquid for inhalation, drug label (DailyMed)

Frequently Asked Questions (FAQ)

Common questions about Isoflo (FAQ)


Q: Does Isoflo have a generic name?

Yes, the active ingredient contained in Isoflo is isoflurane. This is the generic name for the compound, which is classified chemically as a halogenated ether.


Q: Why is Isoflo sometimes used for animals?

Official product information notes its restricted use as an inhalation anesthetic in specific animal species, such as dogs and horses.


Q: Are there any long-term side effects associated with Isoflo use?

Regulatory documents state that research on Isoflo focuses heavily on short-term outcomes measured during and immediately after its use in a procedure. Due to this focus, official information provides limited insight into long-term functional outcomes or effects.


Q: Does Isoflo interact with common pain relievers?

Official documentation states that isoflurane may increase the hepatotoxic effects when used alongside acetaminophen, a common pain reliever. It also notes a dose-sparing effect when co-administered with opioids/narcotics.


Q: Can consuming alcohol affect the use of Isoflo?

Official documents state that a history of chronic alcohol ingestion is noted to cause cross-tolerance. This may be associated with needing a higher concentration of the medicine for the intended effect.


Q: Is Isoflo ever used for chronic (long-term) conditions?

The official purpose is for the induction and maintenance of general anesthesia, which are acute, procedure-based uses. It is not indicated in the regulatory documents for long-term chronic conditions.


Q: Is Isoflo used in minor or major procedures?

The official purpose of Isoflo is to facilitate surgical or complex medical procedures by creating a controlled state of central nervous system depression. It is intended to maintain a steady level of anesthesia during procedures that require the patient to be unaware and pain-free.


Q: Does Isoflo cause drowsiness or sleepiness afterward?

Regulatory guidance advises that for a period of at least 24 hours after receiving a general anesthetic, patients should avoid undertaking hazardous tasks due to potential temporary impairment of alertness and mental function.


Q: Is it true that Isoflo is sometimes called an 'ether'?

Yes, this is based on its chemical classification. Isoflo is a type of synthetic compound that is chemically categorized as a halogenated ether, defining its structure and pharmacological class.


Q: Has Isoflo been studied for its effect on memory?

Clinical studies have examined emergence time, which is the time until a patient awakens after the medicine is discontinued. These studies also include monitoring related to temporary mental function, such as the ability to perform psychometric tests in the immediate post-operative period.


Q: Is Isoflo flammable or explosive?

No, the official description of the active ingredient, isoflurane, states that it is a nonflammable and nonexplosive general inhalation anesthetic agent.


Q: Does Isoflo contain latex or other common allergens?

Official information regarding the product’s composition states that Isoflo is supplied as a clear, colorless, stable liquid containing no additives or chemical stabilizers.


Q: How is Isoflo eliminated from the body?

Isoflurane is minimally processed by the body. It is primarily eliminated from the body via the lungs (respiratory washout) after the administration of the medicine is stopped.


Q: Are there specific warnings for elderly patients using Isoflo?

Regulatory documents indicate that older adult patients typically require lower inspired concentrations for the maintenance of anesthesia compared to younger adults.


Q: What if I have an allergic reaction to Isoflo?

Post-marketing reports document a serious adverse reaction called anaphylaxis associated with halogenated anesthetics.


Q: Does Isoflo affect mood or mental clarity after it wears off?

Less common adverse reactions documented in the post-operative period may include temporary occurrences of mood changes or confusion.


Q: Can Isoflo be used if a patient has a history of breathing problems like asthma?

Caution is advised for patients with a history of asthma or other pre-existing respiratory issues, as the drug is a profound respiratory depressant.


Q: Why is Isoflo always given with oxygen?

The required method of administration dictates that Isoflo must be combined with oxygen or an oxygen/nitrous-oxide mixture. Additionally, the safety information specifies that facilities for oxygen enrichment should be immediately available.


Q: Are there specific genetic conditions that affect how Isoflo works?

Isoflo is contraindicated for individuals with known or suspected genetic susceptibility to Malignant Hyperthermia (MH). Patients with certain neuromuscular disorders are also noted to be vulnerable to perioperative hyperkalemia.


Q: What is the stability requirement for Isoflo during storage?

Official labeling requires Isoflo to be stored at Controlled Room Temperature, typically 20 to 25 C. The container must be kept tightly closed to maintain product integrity.


Q: How quickly does Isoflo start to work?

For adults, initial inspired concentrations are typically used to achieve a surgical level of anesthesia within approximately 7 to 10 minutes.


Q: How long does the effect of Isoflo usually last?

Isoflo is a volatile liquid, a property that allows the level of anesthesia to be adjusted rapidly by the specialist. Studies monitor the time until the patient awakened after the medicine was discontinued.


Q: What are the most commonly reported side effects of Isoflo?

According to official product information, the most common reported adverse reactions are those with an incidence of 1%. These typically include nausea, vomiting, postoperative shivering, and chills.


Q: Can taking other prescription medicines interfere with Isoflo?

Yes, regulatory documents describe several interactions. For example, co-administration with other medicines like non-depolarizing muscle relaxants (e.g., Vecuronium) and opioids/narcotics may significantly affect the required concentration of Isoflo.


Q: What should I do if I forget to mention a medicine to my doctor?

Regulatory documents require the treating professional to be aware of all concurrent medicines, as several known drug interactions (e.g., with Succinylcholine) can cause severe or life-threatening reactions. It is important for the specialist to have a complete and accurate list of all medicines used.


Q: Does Isoflo affect the liver or kidneys?

Isoflo is contraindicated in patients with a known history of severe hepatic (liver) dysfunction following previous exposure to similar agents. However, there is no similar documented warning or contraindication regarding the kidneys.


Q: What is known about using Isoflo during pregnancy?

Caution is advised when administering to a nursing woman, as it is not officially known if the drug is excreted into human milk. The use of Isoflo during pregnancy is generally advised only if the potential benefit justifies the risk.


Q: What does the FDA or other regulatory agencies say about Isoflo?

Isoflurane is an FDA-approved prescription medicine. It is officially indicated for the induction and maintenance of general anesthesia in controlled institutional settings.


Q: Is there a risk of fever after using Isoflo?

While fever is not a listed common side effect, a critical, life-threatening hypermetabolic state called Malignant Hyperthermia can be triggered by Isoflo. This condition is characterized by a rapid and severe rise in body temperature.


Q: Does Isoflo require special monitoring during its use?

Yes, official safety documents mandate continuous, close monitoring of the patient's respiration and hemodynamics (such as blood pressure and heart rate) throughout the anesthetic procedure.


Q: What is the typical concentration or amount used in medicine?

The amount is measured in percentage of inspired concentration. The regulatory labeling provides typical concentration ranges for the specialist to reference, such as 1.5% to 3.0% for induction in adults.

How should Isoflo be stored and disposed of?

Storage and Disposal Requirements for Isoflurane

Isoflurane (Isoflo) must be stored at Controlled Room Temperature, officially defined as mathbf20 to mathbf25 C (mathbf68 to mathbf77 F), with permitted excursions up to mathbf30 C. The product must be stored in its amber-colored bottle and kept tightly closed to maintain container integrity.

Stability and Handling

It is mandatory to keep out of the sight and reach of children.

A specific stability rule requires that carbon dioxide absorbents in the anesthetic circuit should not be allowed to dry out to prevent the formation of carbon monoxide. If the absorbent is suspected to be desiccated, it must be replaced prior to administering Isoflurane.

Disposal

Any unused medicinal product or waste material must be disposed of in accordance with local requirements. Disposal must comply with Federal, State, and local regulations, and spent waste gas charcoal canisters are typically managed as hazardous chemical waste in institutional settings.

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

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