Isoflurane is an active pharmaceutical ingredient in the Halogenated Hydrocarbons group (N01AB). The information below is compiled per regulator from the product labels on record, with direct links to the original documents.
GBOfficial regulatory label· revised December 12, 2025[1]
Isoflurane is general inhalation anaesthetic for use in induction and maintenance.
How to take
GBOfficial regulatory label
CACanada· Health Canada
2 products
Uses
CAOfficial regulatory label· revised March 22, 2025[2]
AND CLINICAL USE ...................................................................................... 3 CONTRAINDICATIONS ............................................................................................................
3 WARNINGS AND PRECAUTIONS .......................................................................................... 4 ADVERSE REACTIONS ............................................................................................................
8 DRUG INTERACTIONS .......................................................................................................... 11 DOSAGE AND ADMINISTRATION ......................................................................................
13 OVERDOSAGE ......................................................................................................................... 15 STORAGE AND STABILITY ..................................................................................................
USUnited States· FDA
1 product
Uses
USOfficial regulatory label· revised November 26, 2025[3]
1 INDICATIONS AND USAGE Isoflurane USP may be used for induction and maintenance of general anesthesia. Adequate data have not been developed to establish its application in obstetrical anesthesia. Isoflurane USP, a general anesthetic, is an inhalation agent indicated for induction and maintenance of general anesthesia.
( 1 )
How to take
Drug interactions
Known interactions involving Isoflurane. Select one for details. This list is informational and not a complete interaction checker.
Interaction data compiled from DDInter (academic, CC-BY). Severity classification only - this is not a complete interaction checker and not medical advice.
[1]MHRA (UK) · PL370710002 · revised December 12, 2025
[2]Health Canada (DPD) · 02231929 · revised March 22, 2025
[3]FDA DailyMed · 13c9c37a-0c3d-45… · revised November 26, 2025 [PDF]
[4]OpenFDA adverse-event reports (US), 12 months ending June 4, 2026.
Information on this page is compiled from public regulatory records. Drugvu is not affiliated with any regulator or pharmaceutical manufacturer. This is not medical advice. Always consult a qualified healthcare professional.
Posology MAC values for Isoflurane vary with age. The table below indicates average MAC values for different age groups. 60% Premedication: Premedication drugs should be selected according to the needs of the patient. The respiratory depressant effect of Isoflurane should be taken into account.
The use of anticholinergic drugs is a matter of choice, but may we advisable for inhalation induction in paediatrics.
Induction:
As Isoflurane has a mild pungency, inhalation should usually be preceded by the use of a short acting barbiturate, or other intravenous induction agent, to prevent coughing. Alternatively, Isoflurane with oxygen or with an oxygen/ nitrous oxide mixture may be administered.
5%. 0% usually produce surgical anaesthesia in 7-10 minutes. 4). 5% in an oxygen/nitrous oxide mixture. 0%) may be required when Isoflurane is given with oxygen alone. 75% isoflurane in a mixture of oxygen/nitrous oxide is suitable to maintain anaesthesia for this procedure.
Arterial pressure levels during maintenance tend to be inversely related to alveolar Isoflurane concentration in the absence of other complicating factors. Provided there are no other complicating factors this is probably due to peripheral vasodilation.
Excessive falls in blood pressure may be due to the depth of anaesthesia and, in such circumstances, can be corrected by reducing the inspired Isoflurane concentration.
Elderly:
As with other agents, lesser concentrations of isoflurane are normally required to maintain surgical anaesthesia in elderly patients. See above for MAC values related to age.
Method of Administration:
Vaporisers specially calibrated for Isoflurane should be used so that the concentration of anaesthetic can be accurately controlled. Isoflurane is not recommended as an induction agent in children.
This is not medical advice. Consult a qualified healthcare professional.
Side effects & warnings
GBOfficial regulatory label· Adverse reactions· revised December 12, 2025[1]
a. Summary of the safety profile Adverse reactions encountered in the administration of Isoflurane are in general dose dependent extensions of pharmaco-physiological effects and include hypotension, respiratory depression and arrhythmias.
8). Shivering, nausea, vomiting, ileus, agitation and delirium have been observed in the post-operative period. Cardiac arrest, bradycardia and tachycardia have been observed with general inhalation anaesthetic drugs including isoflurane.
Reports of QT prolongation, associated with torsade de pointes (in exceptional cases, fatal) have been received. b. Tabulated summary of adverse reactions The following table displays adverse reactions reported in clinical trials and from post-marketing experience.
Frequency cannot be estimated from the available data, therefore it is "not known". 8(c). 4. 3In patients undergoing induced abortion. 4. 4May cause a slight decrease in intellectual function for 2-4 days after anaesthesia. 4. 5Small changes in moods and symptoms may persist for up to 6 days.
4. c. Description of selected adverse reactions Transient increases in blood bilirubin, blood glucose and serum creatinine with decrease in BUN, serum cholesterol and alkaline phosphatase have been observed. As with other general anaesthetics, transient elevations in white blood count have been observed even in the absence of surgical stress.
Rare reports of hypersensitivity (including dermatitis contact, rash, dyspnoea, wheezing, chest discomfort, swelling face, or anaphylactic reaction) have been received, especially in association with long-term occupational exposure to inhaled anaesthetic agents, including isoflurane.
, methacholine challenge). The etiology of anaphylactic reactions experienced during inhalational anaesthetic exposure is, however, unclear because of the exposure to multiple concomitant drugs, many of which are known to cause such reactions.
Minimally raised levels of serum inorganic fluoride occur during and after isoflurane anaesthesia, due to biodegradation of the agent. 4 μmol/l in one study) could cause renal toxicity, as these are well below the proposed threshold levels for kidney toxicity.
d. Paediatric population Use of inhaled anaesthetic agents has been associated with rare increases in serum potassium levels that have resulted in cardiac arrhythmias and death in paediatric patients during the post-operative period.
) During the induction of anaesthesia, saliva flow and tracheobronchial secretion can increase and can be the cause of laryngospasm. ) e.
Other special populations Neuromuscular disease:
Use of inhaled anaesthetic agents has been associated with rare increases in serum potassium levels that have resulted in cardiac arrhythmias and death in paediatric patients during the post-operative period. Patients with latent as well as overt neuromuscular disease, particularly Duchenne muscular dystrophy, appear to be most vulnerable.
4).
Elderly:
Lesser concentrations of isoflurane are normally required to maintain surgical anaesthesia in elderly patients. ) Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important.
It allows continued monitoring of the benefit/risk balance of the medicinal product. uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
GBOfficial regulatory label· Warnings and precautions· revised December 12, 2025[1]
Vaporisers specially calibrated for isoflurane should be used so that the concentration of anaesthetic delivered can be accurately controlled. Hypotension and respiratory depression increase as anaesthesia is deepened. Reports of QT prolongation, associated with torsade de pointes (in exceptional cases, fatal), have been received.
Caution should be exercised when administering isoflurane to patients at risk for QT prolongation. Caution should be exercised in administering general anaesthesia, including isoflurane, to patients with mitochondrial disorders. Isoflurane, like other inhalational agents, has relaxant effects on the uterus with the potential risk for uterine bleeding.
Clinical judgement should be observed when using isoflurane during obstetric anaesthesia. 6). , desflurane, enflurane and isoflurane). No clinically significant concentrations of carbon monoxide are produced in the presence of normally hydrated absorbents.
Care should be taken to follow manufacturer's instructions for CO2 absorbents. Isoflurane has been reported to interact with dry carbon dioxide absorbents during closed circuit anaesthesia, to form carbon monoxide. In order to minimize the risk of formation of carbon monoxide in rebreathing circuits and the possibility of elevated carboxyhaemoglobin levels, carbon dioxide adsorbents should not be allowed to dry out.
g. Baralyme). When a clinician suspects that the CO2 absorbent may be desiccated, it should be replaced before administration of isoflurane. The colour indicator of most CO2 absorbents does not necessarily change as a result of desiccation.
Therefore, the lack of significant colour change should not be taken as an assurance of adequate hydration. CO2 absorbents should be replaced routinely regardless of the state of the colour indicator. General Because levels of anaesthesia can be altered easily and quickly with Isoflurane, only vaporisers which produce a predictable concentration with a good degree of accuracy or techniques during which inspired or expired concentrations can be monitored, should be used.
The degree of hypotension and respiratory depression may provide some indication of anaesthetic depth. As with any potent general anaesthetic, isoflurane should only be administered in an adequately equipped anaesthetising environment by those who are familiar with the pharmacology of the drug and qualified by training and experience to manage the anaesthetised patient.
This is not medical advice. Consult a qualified healthcare professional.
Who should not take it
GBOfficial regulatory label· Contraindications· revised December 12, 2025[1]
Isoflurane is contraindicated in patients with known sensitivity to Isoflurane or to other halogenated anaesthetics. It is also contraindicated in patients with known or suspected genetic susceptibility to malignant hyperthermia.
This is not medical advice. Consult a qualified healthcare professional.
17 DOSAGE FORMS, COMPOSITION AND PACKAGING ..................................................... 18 PHARMACEUTICAL INFORMATION .................................................................................. 18 DETAILED PHARMACOLOGY .............................................................................................
9% None INDICATIONS AND CLINICAL USE Isoflurane is indicated for: induction and maintenance of general anesthesia.
Geriatrics (> 65 years of age):
The minimum alveolar concentration (MAC) of isoflurane decreases with increasing patient age. The dose should be adjusted accordingly. See table in DOSAGE AND ADMINISTRATION.
Pediatrics (0 ‒ 16 years of age):
MAC values for children up to 5 years of age, including those for preterm neonates, are available. Isoflurane MAC decreases with increasing age, except for both term and preterm neonates, measured approximately at 1 month of age. See table in DOSAGE AND ADMINISTRATION.
CONTRAINDICATIONS Isoflurane is contraindicated in patients: with known hypersensitivity to isoflurane or to other halogenated inhalational anesthetics. with a history of hepatitis due to a halogenated inhalational anesthetic or in whom liver dysfunction, jaundice or unexplained fever, leucocytosis, or eosinophilia has occurred after a previous halogenated anesthetic administration (see WARNINGS AND PRECAUTIONS).
with known or suspected genetic susceptibility to malignant hyperthermia, or with a history of malignant hyperthermia (see WARNINGS AND PRECAUTIONS). in whom general anesthesia is contraindicated. Isoflurane USP - Product Monograph Page 4 of 26 WARNINGS AND PRECAUTIONS Serious Warnings and Precautions Isoflurane should be administered only by persons trained in the administration of general anesthesia.
Facilities for maintenance of a patent airway, artificial ventilation, oxygen enrichment, and circulatory resuscitation must be immediately available. Isoflurane may trigger Malignant Hyperthermia in susceptible individuals and fatal outcomes have been reported (see Malignant Hyperthermia section below).
Isoflurane use may lead to Perioperative Hyperkalemia in patients with neuromuscular disorders (see Hyperkalemia section below). General Deliver isoflurane from a vaporizer specifically designed and designated for use with isoflurane.
Monitoring of end-tidal concentration may be considered. The safety of repeated anesthesia with isoflurane has not been studied. As with all halogenated anesthetics, repeated anesthesia within a short period of time should be approached with caution.
Patients should be advised that performance of activities requiring mental alertness and motor coordination, such as driving a vehicle or operating machinery, may be impaired for at least 24 hours following administration of general anesthesia.
The following reactions have been reported following occupational exposure to isoflurane: dyspnea, bronchospasm, stridor, cough, dizziness, paresthesia, hepatic reactions, flushing, rash, contact dermatitis, erythema, periorbital edema, eye irritation, conjunctival hyperemia, and headache.
See ADVERSE REACTIONS, Post-Market Adverse Drug Reactions. Cardiovascular Use in Patients With or at Risk for Elevations of Intracranial Pressure Isoflurane can increase cerebral blood flow and hence intracranial pressure (ICP), and therefore should be used with special care in patients with pre-existing increases in intracranial pressure.
, optimized hyperventilation). Use in Hypovolemic, Hypotensive, or Hemodynamically Compromised Patients Isoflurane causes a dose-dependent reduction in systemic vascular resistance and blood pressure. Particular care must be taken when selecting the dosage for patients who are hypovolemic, hypotensive, or otherwise hemodynamically compromised, for example, due to concomitant medications.
Excessive decreases in blood pressure may be related to depth of anesthesia and Isoflurane USP - Product Monograph Page 5 of 26 respond to reducing the inspired concentration of isoflurane. Use in Patients with Coronary Artery Disease In patients with coronary artery […]
Side effects & warnings
CAOfficial regulatory label· Warnings and precautions· revised March 22, 2025[2]
Serious Warnings and Precautions Isoflurane should be administered only by persons trained in the administration of general anesthesia. Facilities for maintenance of a patent airway, artificial ventilation, oxygen enrichment, and circulatory resuscitation must be immediately available.
Isoflurane may trigger Malignant Hyperthermia in susceptible individuals and fatal outcomes have been reported (see Malignant Hyperthermia section below). Isoflurane use may lead to Perioperative Hyperkalemia in patients with neuromuscular disorders (see Hyperkalemia section below).
General Deliver isoflurane from a vaporizer specifically designed and designated for use with isoflurane. Monitoring of end-tidal concentration may be considered. The safety of repeated anesthesia with isoflurane has not been studied.
As with all halogenated anesthetics, repeated anesthesia within a short period of time should be approached with caution. Patients should be advised that performance of activities requiring mental alertness and motor coordination, such as driving a vehicle or operating machinery, may be impaired for at least 24 hours following administration of general anesthesia.
The following reactions have been reported following occupational exposure to isoflurane: dyspnea, bronchospasm, stridor, cough, dizziness, paresthesia, hepatic reactions, flushing, rash, contact dermatitis, erythema, periorbital edema, eye irritation, conjunctival hyperemia, and headache.
See ADVERSE REACTIONS, Post-Market Adverse Drug Reactions. Cardiovascular Use in Patients With or at Risk for Elevations of Intracranial Pressure Isoflurane can increase cerebral blood flow and hence intracranial pressure (ICP), and therefore should be used with special care in patients with pre-existing increases in intracranial pressure.
, optimized hyperventilation). Use in Hypovolemic, Hypotensive, or Hemodynamically Compromised Patients Isoflurane causes a dose-dependent reduction in systemic vascular resistance and blood pressure. Particular care must be taken when selecting the dosage for patients who are hypovolemic, hypotensive, or otherwise hemodynamically compromised, for example, due to concomitant medications.
Excessive decreases in blood pressure may be related to depth of anesthesia and Isoflurane USP - Product Monograph Page 5 of 26 respond to reducing the inspired concentration of isoflurane. Use in Patients with Coronary Artery Disease In patients with coronary artery disease, maintenance of normal hemodynamics is important in order to avoid myocardial ischemia.
Isoflurane can cause dose dependent coronary vasodilation and has been shown to divert blood from collateral-dependent myocardium to normally perfused areas in an animal model (“coronary steal”). The extent to which coronary steal occurs in patients with steal-prone coronary anatomy is unclear.
Isoflurane should be used with caution in such patients. QT Prolongation Caution should be exercised when administering isoflurane to susceptible patients. Isoflurane can prolong the QT interval in adults and children. , patients with congenital Long QT Syndrome or patients taking drugs that can prolong the QT interval).
Isolated post-market cases of cardiac arrhythmia associated with the QT prolongation have been reported. There are very rare reports of torsade de pointes. Endocrine and Metabolism Malignant Hyperthermia In susceptible individuals, isoflurane anesthesia may trigger a skeletal muscle hypermetabolic state leading to high oxygen demand and the clinical syndrome known as malignant hyperthermia.
The syndrome includes features such as high core body temperature, muscle rigidity, tachycardia, tachypnea, cyanosis, arrhythmias, and unstable blood pressure. An increase in overall metabolism may be reflected in an elevated temperature (which may rise rapidly early or late in the case, but usually is not the first sign of augmented metabolism) and an increased usage of the CO2 absorption system (hot canister).
PaO2 and pH may decrease, and hyperkalemia and a base deficit may appear. , isoflurane), administration of intravenous dantrolene sodium, and application of supportive therapy. Such therapy includes vigorous efforts to decrease the patient’s body temperature to normal, respiratory and circulatory support as indicated, and management of electrolyte-fluid-acid-base derangements.
Renal failure may appear later, and urine flow should be sustained if possible. A number of fatal outcomes from malignant hyperthermia have been reported with isoflurane. See CONTRAINDICATIONS. Hyperkalemia Use of inhaled anesthetic agents has been associated with rare increases in serum potassium levels that have resulted in cardiac arrhythmias and death in pediatric patients intraoperatively and postoperatively.
Patients with latent as well as overt neuromuscular disease, particularly Duchenne muscular dystrophy, appear to be most vulnerable. Concomitant use of succinylcholine has been associated with most, but not all, of these cases. These patients also experienced significant elevations in serum creatinine kinase levels and, in some cases, changes in urine consistent with myoglobinuria.
Despite the similarity in presentation to malignant hyperthermia, none of these patients exhibited signs or symptoms of muscle rigidity or hypermetabolic state. Early and aggressive intervention to treat the hyperkalemia and resistant Isoflurane USP - Product Monograph Page 6 of 26 arrhythmias is recommended, as is subsequent evaluation for latent neuromuscular disease.
Hematologic Intraoperative elevation of blood glucose and white blood count may occur. The effect of general anesthetics […]
This is not medical advice. Consult a qualified healthcare professional.
2 DOSAGE AND ADMINISTRATION • Isoflurane USP should be administered only by persons trained in the administration of general anesthesia. Isoflurane USP should only be delivered using a vaporizer specifically designed and designated for use with isoflurane.
( 2 ) • The administration of general anesthesia must be individualized and titrated based on the patient’s age and clinical status. 1 Important Dosage and Administration Information Isoflurane should be administered only by persons trained in the administration of general anesthesia.
Facilities for maintenance of a patent airway, artificial ventilation, oxygen enrichment, and circulatory resuscitation must be immediately available. Isoflurane is administered by inhalation. Isoflurane should be delivered from a vaporizer specifically designed for use with isoflurane.
Dosage for induction and maintenance must be individualized and titrated to the desired effect according to the patient’s age and clinical status. With the exception of neonates, the minimum alveolar concentration (MAC) of isoflurane decreases with increasing patient age.
Nitrous oxide decreases the MAC of isoflurane (see Table 1 ). Opioids decrease the MAC of isoflurane [see Drug Interactions (7) ]. Isoflurane potentiates the muscle relaxant effect of all neuromuscular blockers and decreases the required doses of neuromuscular blocking agents [see Drug Interactions (7) ] .
The dose should be adjusted accordingly. , monitoring of the electrocardiogram, blood pressure, oxygen saturation, and end tidal CO 2 ). Isoflurane is a profound respiratory depressant. Excessive respiratory depression may be related to depth of anesthesia and respond to decreasing the inspired concentration of isoflurane.
The depressant effect is accentuated by concurrent use of opioids and other respiratory depressants. Respiration should be closely monitored and assisted or controlled ventilation employed when necessary. 2 Premedication Premedication should be selected according to the need of the individual patient, taking into account that secretions are weakly stimulated by Isoflurane USP, and the heart rate tends to be increased.
3 Induction Induction with isoflurane in oxygen or in combination with oxygen-nitrous oxide mixtures may produce coughing, breath holding, laryngospasm and bronchospasm, which increases with the concentration of isoflurane. These difficulties may be avoided by the use of a hypnotic dose of an ultra-short-acting barbiturate.
5 to 3% isoflurane usually produce surgical anesthesia in 7 to 10 minutes. 37% Dosage for induction and maintenance must be individualized and titrated to the desired effect according to the patient’s age and clinical status. 5% concentration when nitrous oxide is used concomitantly.
5 to 1% may be required when isoflurane is given using oxygen alone. If added relaxation is required, supplemental doses of neuromuscular blocking agents may be used. The level of blood pressure during maintenance is an inverse function of isoflurane concentration in the absence of other complicating problems.
Excessive decreases may be due to depth of anesthesia and in such instances may be corrected by lightening anesthesia. Isoflurane causes a dose-dependent reduction in systemic vascular resistance and blood pressure. , due to concomitant medications.
Isoflurane USP markedly increases cerebral blood flow at deeper levels of anesthesia to produce a transient increase in intracranial pressure. In patients with or at risk for elevations of intracranial pressure (ICP), administer isoflurane in conjunction with ICP- reducing strategies, as clinically appropriate.
5 Use in Patients with Coronary Artery Disease Regardless of the anesthetics employed, maintenance of normal hemodynamics is important to the avoidance of myocardial ischemia in patients with coronary artery disease. Isoflurane can cause dose-dependent coronary vasodilation and has been shown to divert blood from collateral-dependent myocardium to normally perfused areas in an animal model (“coronary steal”).
The extent to which coronary steal occurs in patients with steal-prone coronary anatomy is unclear. , ECG, blood pressure) during isoflurane administration. Consider additional cardiac monitoring in patients with known coronary artery disease, as clinically necessary.
This is not medical advice. Consult a qualified healthcare professional.
Most-reported reactions to the US regulator (12 mo to June 4, 2026): 56 reports total. [4]
Off Label Use 10
Hyperthermia Malignant 7
Dyskinesia 6
Brain Injury 5
Drug Withdrawal Syndrome 5
Hypotension 5
Renal Failure 5
Rhabdomyolysis 5
Seizure 5
Subdural Effusion 5
Bradycardia 4
Drug Ineffective 4
Side effects & warnings
USOfficial regulatory label· Adverse reactions· revised November 26, 2025[3]
6 ADVERSE REACTIONS Most common adverse reactions (incidence > 5%) are agitation, cough, breath holding, nausea, chills/shivering, vomiting, laryngospasm, delirium. 1 ) To report SUSPECTED ADVERSE REACTIONS, contact Piramal Critical Care, Inc.
gov/medwatch. 1 Clinical Trials Experience The following adverse reactions were identified from controlled clinical trials of adult and pediatric subjects exposed to Isoflurane USP. The trials were conducted using a variety of pre-medications, other anesthetics, and surgical procedures of varying lengths.
The most serious reported adverse reactions in alphabetical order are agitation, arrhythmia, breath holding, elevated liver enzyme, hypotension and laryngospasm. The most frequent adverse reactions (incidence ³ 5%) described in Table 1 are agitation, breath holding, chills/shivering, cough, delirium, laryngospasm, nausea, and vomiting.
Adverse reactions with an incidence between 1% and 5% are provided in Table 2. Adverse reactions with an incidence less than 1% are provided in Table 3. Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
, patients receiving inhalation induction). 2 Reflects the number of patients with recorded body temperature measurements. , patients receiving inhalation induction). 0% (N=359) 3 1 Reflects the number of patients interviewed by a physician in the recovery period.
2 Reflects the number of recorded electroencephalograms. , patients receiving inhalation induction). The following adverse reactions (see Table 5 ) were observed, but due to limited data, frequency could not be determined. 2 Post-Marketing Experience The following adverse reactions have been identified during post-approval use of Isoflurane USP.
Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Post-marketing adverse reactions are listed by MedDRA System Organ Class (SOC), then by preferred term in order of decreasing severity.
BLOOD AND LYMPHATIC SYSTEM DISORDERS:
Carboxyhemoglobin increased IMMUNE SYSTEM DISORDERS: Anaphylactic reaction METABOLISM AND NUTRITION DISORDERS: Hyperkalemia in patients with underlying myopathies PSYCHIATRIC DISORDERS: Withdrawal syndrome (following multi-day exposure; symptoms include seizure, hallucination, ataxia, agitation, confusion) NERVOUS SYSTEM DISORDERS: Brain edema, Intracranial pressure increased, Migraine, Myoclonus, Nystagmus, Pupils unequal, Headache CARDIAC DISORDERS: Cardiac arrest, Ventricular fibrillation, Torsade de pointes, Myocardial infarction, Myocardial ischemia, Atrioventricular block complete, Atrioventricular block second degree, Atrial fibrillation, Electrocardiogram QT prolonged, Atrioventricular block first degree, Ventricular tachycardia, Ventricular extrasystoles, Tachycardia, Bradycardia, Cardiac output decreased VASCULAR DISORDERS: Flushing RESPIRATORY, THORACIC, AND MEDIASTINAL DISORDERS: Apnea, Hypoxia, Bronchospasm, Airway obstruction, Respiratory depression, Hypercapnia, Stridor, Hiccough GASTROINTESTINAL DISORDERS: Pancreatitis HEPATOBILIARY DISORDERS: Hepatic necrosis, Hepatic failure, Hepatitis fulminant, Cholestatic hepatitis, Hepatitis, Hepatic steatosis, Jaundice, Gamma- glutamyltransferase increased SKIN AND SUBCUTANEOUS TISSUE DISORDERS: Rash MUSCULOSKELETAL, CONNECTIVE TISSUE AND BONE DISORDERS: Rhabdomyolysis RENAL AND URINARY DISORDERS: Acute renal failure**, Oliguria** GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS: Malignant hyperthermia, hypothermia INJURY, POISONING, AND PROCEDURAL COMPLICATIONS*: Unwanted awareness during anesthesia; Dyspnea, Bronchospasm, Stridor, Cough, Dizziness, Paresthesia, Hepatic reactions, Flushing, Rash, Contact dermatitis, Erythema, Periorbital edema, Eye irritation, Conjunctival hyperemia, Headache *All reactions categorized within this SOC, with the exception of, Unwanted awareness during anesthesia, were from occupational exposure in non-patients.
**Cases of acute renal failure and oliguria have been reported after isoflurane anesthesia. These events may be secondary to hypotension or other effects of isoflurane.
USOfficial regulatory label· Warnings and precautions· revised November 26, 2025[3]
5 WARNINGS AND PRECAUTIONS • Malignant Hyperthermia : Malignant hyperthermia may occur, especially in individuals with known or suspected susceptibility based on genetic factors or family history. Discontinue triggering agents, administer intravenous dantrolene sodium, and apply supportive therapies.
1 ) • Perioperative Hyperkalemia : Perioperative hyperkalemia may occur. Patients with latent or overt neuromuscular disease, particularly with Duchenne muscular dystrophy, appear to be most vulnerable. Early, aggressive intervention is recommended.
2 ) • Hepatic Reactions : May cause sensitivity hepatitis in patients sensitized by previous exposure to halogenated anesthetics. Approach repeated anesthesia with caution. 3 ) • Hypersensitivity Reactions : Allergic-type hypersensitivity reactions, including anaphylaxis, have been reported with isoflurane.
4 ) • Abortions : Increased blood loss comparable to that seen with halothane has been observed in patients undergoing abortions. 5 ) • QT Prolongation : Carefully monitor cardiac rhythm when administering Isoflurane USP to susceptible patients.
6 ) • Interactions with Desiccated Carbon Dioxide (CO 2 ) Absorbents: May react with desiccated CO 2 absorbents to produce carbon monoxide. Replace desiccated CO 2 absorbent before administration of Isoflurane USP. 7 ) • Pediatric Neurotoxicity : In developing animals, exposures greater than 3 hours cause neurotoxicity.
Weigh benefits against potential risks when considering elective procedures in children under 3 years old. 1 Malignant Hyperthermia In susceptible individuals, volatile anesthetic agents, including Isoflurane USP, may trigger malignant hyperthermia, a skeletal muscle hypermetabolic state leading to high oxygen demand.
Fatal outcomes of malignant hyperthermia have been reported. The risk of developing malignant hyperthermia increases with the concomitant administration of succinylcholine and volatile anesthetic agents. 5) ]. , particularly that unresponsive to deepening anesthesia or analgesic medication administration), tachypnea, cyanosis, arrhythmias, hypovolemia, and hemodynamic instability.
Skin mottling, coagulopathies, and renal failure may occur later in the course of the hypermetabolic process. Successful treatment of malignant hyperthermia depends on early recognition of the clinical signs. , volatile anesthetic agents and succinylcholine), administer intravenous dantrolene sodium, and initiate supportive therapies.
This is not medical advice. Consult a qualified healthcare professional.
Who should not take it
USOfficial regulatory label· Contraindications· revised November 26, 2025[3]
4 CONTRAINDICATIONS Isoflurane USP is contraindicated in patients: • in whom general anesthesia is contraindicated. 3 )]. 5 )]. , jaundice associated with fever and/or eosinophilia) after anesthesia with isoflurane or other halogenated inhalational anesthetics.
, jaundice associated with fever and/or eosinophilia) after anesthesia with Isoflurane USP or other halogenated inhalational anesthetics ( 4 )
This is not medical advice. Consult a qualified healthcare professional.
Reports demonstrate that Isoflurane can produce hepatic injury ranging from mild transient increases of liver enzymes to fatal hepatic necrosis in very rare instances. It has been reported that previous exposure to halogenated hydrocarbon anaesthetics, especially if the interval is less than 3 months, may increase the potential for hepatic injury.
Cirrhosis, viral hepatitis or other pre-existing liver disease can be a reason to select an anaesthetic other than a halogenated anaesthetic. Regardless of the anaesthetics employed, maintenance of normal haemodynamics is important to the avoidance of myocardial ischaemia in patients with coronary artery disease.
Isoflurane markedly increases cerebral blood flow at deeper levels of anaesthesia. There may be a transient rise in cerebral spinal fluid pressure which is fully reversible with hyperventilation. Isoflurane must be used with caution in patients with increased intracranial pressure.
In such cases hyperventilation may be necessary. Use of isoflurane in hypovolaemic, hypotensive and debilitated patients has not been extensively investigated. A lower concentration of isoflurane is recommended for use in these patients.
All commonly used muscle relaxants are markedly potentiated by isoflurane, the effect being most profound with non-depolarising agents. Isoflurane may cause a slight decrease in intellectual function for 2-4 days following anaesthesia.
Small changes in moods and symptoms may persist for up to 6 days after administration. 7). A potentiation of neuromuscular fatigue can be seen in patients with neuromuscular diseases, such as myasthenia gravis. Isoflurane should be used with caution in these patients.
8). Isoflurane may cause respiratory depression which may be augmented by narcotic premedication or other agents causing respiratory depression. 8). 8). Paediatric Population Children under two years of age Caution should be exercised when Isoflurane is used in small children due to limited experience with this patient group.
During the induction of anaesthesia, saliva flow and tracheobronchial secretion can increase and can be the cause of laryngospasm, particularly in children. Malignant Hyperthermia In susceptible individuals, isoflurane anaesthesia may trigger a skeletal muscle hypermetabolic state leading to high oxygen demand and the clinical syndrome known as malignant hyperthermia.
The syndrome includes nonspecific features such as […]
Consult prescribing information for intravenous dantrolene sodium for additional information on patient management. Supportive therapies include administration of supplemental oxygen and respiratory support based on clinical need, maintenance of hemodynamic stability and adequate urinary output, management of fluid and electrolyte balance, correction of acid base derangements, and institution of measures to control rising temperature.
2 Perioperative Hyperkalemia Use of inhaled anesthetic agents has been associated with rare increases in serum potassium levels that have resulted in cardiac arrhythmias and death in pediatric patients during the postoperative period.
Patients with latent as well as overt neuromuscular disease, particularly Duchenne muscular dystrophy, appear to be most vulnerable. Concomitant use of succinylcholine has been associated with most, but not all, of these cases. These patients also experienced significant elevations in serum creatinine kinase levels and, in some cases, changes in urine consistent with myoglobinuria.
Despite the similarity in presentation to malignant hyperthermia, none of these patients exhibited signs or symptoms of muscle rigidity or hypermetabolic state. Early and aggressive intervention to treat the hyperkalemia and resistant arrhythmias is recommended, as is subsequent evaluation for latent neuromuscular disease.
3 Hepatic Reactions Cases of mild, moderate and severe postoperative hepatic dysfunction or hepatitis with or without jaundice, including fatal hepatic necrosis and hepatic failure, have been reported with isoflurane. Such reactions can represent hypersensitivity hepatitis, a known risk of exposure to halogenated anesthetics, including isoflurane.
As with other halogenated anesthetic agents, Isoflurane USP may cause sensitivity hepatitis in patients who have been sensitized by previous exposure to halogenated anesthetics [see Contraindications ( 4 )]. Clinical judgment should be exercised when isoflurane is used in patients with underlying hepatic conditions or under treatment with drugs known to cause hepatic dysfunction.
[see Contraindications (4) ]. As with all halogenated anesthetics, repeated anesthetics within a short period of time may result in increased effects, particularly in patients with underlying hepatic conditions, or additive effects in patients treated with drugs known to cause hepatic dysfunction.
Evaluate the need for repeated exposure in each individual patient and adjust the dose of isoflurane based on signs and symptoms of adequate depth of anesthesia if repeated exposure in a short period of time is clinically indicated.
4 Hypersensitivity Reactions Allergic-type hypersensitivity reactions, including anaphylaxis, have been reported with isoflurane. Manifestations of such reactions have included hypotension, rash, difficulty breathing and cardiovascular collapse.
5 Abortions Increased blood loss comparable to that seen with halothane has been observed in patients undergoing abortions. 6 QT Prolongation QT prolongation, with rare instances of torsade de pointes, have been reported. , patients with congenital Long QT Syndrome or patients taking drugs that can prolong the QT interval).
7 Interactions with Desiccated Carbon Dioxide Absorbents Isoflurane USP, like some other inhalational anesthetics, can react with desiccated carbon dioxide (CO 2 ) absorbents to produce carbon monoxide, which may result in elevated levels of carboxyhemoglobin in some patients.
Barium hydroxide lime and soda lime become desiccated when fresh gases are passed through the CO 2 absorber canister at highflow rates over many hours or days. When a clinician suspects that CO 2 absorbent may be desiccated, it should be replaced before the administration of Isoflurane USP.
The color indicator of most CO 2 absorbents does not necessarily change as a result of desiccation. Therefore, the lack of significant color change should not be taken as assurance of adequate hydration of the CO 2 absorbent material.
CO 2 absorbents should be replaced routinely regardless of the state of color indicator following current manufacturer’s guidelines for use of anesthesiology equipment. 8 Pediatric Neurotoxicity Published animal studies demonstrate that the administration of anesthetic and sedation drugs that block NMDA receptors and/or potentiate GABA activity increase neuronal apoptosis in the developing brain and result in long-term cognitive deficits when used for longer than 3 hours.
The clinical significance of these findings is not clear. 2) ]. Some published studies in children suggest that similar deficits may occur after repeated or prolonged exposures to anesthetic agents early in life and may result in adverse cognitive or behavioral effects.
These studies have substantial limitations, and it is not clear if the observed effects are due to the anesthetic/sedation drug administration or other factors such as the surgery or underlying illness. Anesthetic and sedation drugs are a necessary part of the care of children needing surgery, other procedures, or tests that cannot be delayed, and no specific medications have been shown to be safer than any other.
Decisions regarding the timing of any elective procedures requiring anesthesia should take into consideration the benefits of the procedure weighed against the potential risks. 9 Laboratory Tests Transient increases in BSP retention, blood glucose and serum creatinine with decrease in BUN, serum cholesterol and alkaline phosphatase have been observed.