Note: Coughing, breath-holding, bronchospasm, or laryngospasm may occur during induction; use of an ultra short-acting barbiturate may avoid these symptoms. MAC is increased in the young and decreased in the elderly. Premedication should be selected according to the need of the individual patient, taking into account that secretions are weakly stimulated by isoflurane, and the heart rate tends to be increased. Dosage must be individualized based on patient response.
Anesthesia: Inhalation:
Induction: 1.5% to 3% isoflurane with oxygen or oxygen-nitrous oxide mixture.
Maintenance: With nitrous oxide: 1% to 2.5%; additional 0.5% to 1% with oxygen alone.
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in the manufacturer’s labeling.
There are no dosage adjustments provided in the manufacturer’s labeling; use with caution.
Anesthesia: Inhalation: Refer to adult dosing.
There are no dosage adjustments provided in the manufacturer’s labeling.
There are no dosage adjustments provided in the manufacturer’s labeling.
Refer to adult dosing. Minimum alveolar concentration is decreased in the elderly.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Inhalation:
Forane: USP: >= 99.9 mL/100 mL (100 mL, 250 mL)
Terrell: USP: >= 99.9 mL/100 mL (100 mL, 250 mL)
Generic: USP: >= 99.9 mL/100 mL (100 mL, 250 mL)
Yes
Via isoflurane-specific calibrated vaporizer or vaporizer with calculated flow required
Inhalation: Administer via isoflurane-specific calibrated vaporizer or vaporizer with calculated flow required
Anesthesia: For induction and maintenance of general anesthesia. Adequate data have not been developed to establish its application in obstetrical anesthesia.
Isoflurane may be confused with enflurane
The Institute for Safe Medication Practices (ISMP) includes this medication among its list of drug classes which have a heightened risk of causing significant patient harm when used in error.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Adverse reactions reported in adult and pediatric patients.
>10%:
Gastrointestinal: Nausea (recovery: 15%)
Nervous system: Agitation (induction: 52%), chills (≤14%), shivering (≤14%)
Respiratory: Breath-holding (induction: 24%; maintenance: 1%), cough (induction: 28%; maintenance: 4%)
1% to 10%:
Cardiovascular: Atrial arrhythmia (intraoperative: 2%), atrioventricular nodal arrhythmia (intraoperative: 2% to 4%), cardiac arrhythmia (postoperative: 1%), ventricular arrhythmia (intraoperative: 2% to 3%)
Gastrointestinal: Retching (induction and maintenance: ≤1%), vomiting (recovery: 10%; induction: <1%)
Nervous system: Delirium (6%), involuntary muscle movements (maintenance: 2%)
Neuromuscular & skeletal: Laryngospasm (induction: 8%; maintenance: <1%)
<1%:
Cardiovascular: Hypertension (intraoperative and postoperative), hypotension (intraoperative and postoperative)
Dermatologic: Diaphoresis (induction)
Nervous system: Abnormal electroencephalogram (convulsive pattern), mood changes, nightmares, seizure
Respiratory: Change in bronchial secretions (induction and maintenance)
Frequency not defined:
Endocrine & metabolic: Decreased blood urea nitrogen, decreased serum cholesterol, increased lactate dehydrogenase, increased serum glucose
Gastrointestinal: Intestinal obstruction
Hematologic & oncologic: Leukocytosis
Hepatic: Abnormal hepatic function tests (bromsulphthalein clearance decreased), decreased serum alkaline phosphatase, increased serum alanine aminotransferase, increased serum alkaline phosphatase, increased serum aspartate aminotransferase, increased serum bilirubin
Nervous system: Ataxia, cognitive dysfunction, confusion, dizziness, drowsiness, fatigue, nervousness
Neuromuscular & skeletal: Asthenia, myalgia
Renal: Increased serum creatinine
Postmarketing:
Cardiovascular: Acute myocardial infarction, atrial fibrillation, bradycardia, complete atrioventricular block, first degree atrioventricular block, flushing, ischemic heart disease, low cardiac output, prolonged QT interval on ECG, second degree atrioventricular block, tachycardia, torsades de pointes, ventricular fibrillation, ventricular premature contractions, ventricular tachycardia
Dermatologic: Skin rash
Endocrine & metabolic: Hyperkalemia (with underlying myopathies or perioperative), increased gamma-glutamyl transferase
Gastrointestinal: Hiccups, pancreatitis
Genitourinary: Oliguria
Hematologic & oncologic: Increased hemoglobin (carboxyhemoglobin)
Hepatic: Cholestatic hepatitis, fulminant hepatitis, hepatic failure, hepatic necrosis, hepatitis, hepatotoxicity (idiosyncratic; Chalasani 2014), jaundice, liver steatosis
Hypersensitivity: Anaphylaxis, hypersensitivity reaction
Nervous system: Awareness under anesthesia without pain, brain edema, headache, hypothermia, increased intracranial pressure, malignant hyperthermia, migraine, myoclonus, withdrawal syndrome (following multi-day exposure)
Neuromuscular & skeletal: Rhabdomyolysis
Ophthalmic: Anisocoria, nystagmus disorder
Renal: Acute kidney injury
Respiratory: Airway obstruction, apnea, bronchospasm, hypercapnia, hypoxia, respiratory depression, stridor
Known sensitivity to isoflurane, other halogenated agents, or any component of the formulation; patients in whom general anesthesia is contraindicated; known or suspected genetic susceptibility to malignant hyperthermia; history of hepatitis due to a halogenated inhalational anesthetic or a history of unexplained moderate to severe liver dysfunction (eg, jaundice associated with fever and/or eosinophilia) after anesthesia with isoflurane or other halogenated inhalational anesthetics.
Concerns related to adverse effects:
• Cardiovascular effects: Decrease in BP is dose dependent due to peripheral vasodilation; cardiac output is maintained. Use caution in patients who are hypovolemic, hypotensive, or hemodynamically compromised; use caution in patients with coronary artery disease to avoid risk of myocardial ischemia. May prolong the QT interval and rarely torsades de pointes; use caution in patients at risk of QT prolongation. May produce cardiac steal (due to coronary vasodilation) and reflex tachycardia, but does not depress cardiac conduction nor does it sensitize the myocardium to catecholamine-induced arrhythmias like halothane (not available in the United States) (Golembiewski 2004).
• CNS depression: Advise patients to wait at least 24 hours after administration before engaging in activities which require mental alertness (operating machinery or driving).
• Decreased blood flow: May cause decrease in hepatic, renal, and splenic blood flow (Gelman 1984).
• Hepatic effects: Postoperative mild to severe hepatic dysfunction (including fatal hepatic necrosis and hepatic failure) and hepatitis with or without jaundice have been reported; may cause sensitivity hepatitis in patients who have been sensitized by previous exposure to halogenated anesthetics. Risk may be increased with repeated isoflurane exposure in a short time.
• Hyperkalemia: Use of inhaled anesthetics has been associated with rare cases of perioperative hyperkalemia that have resulted in cardiac arrhythmias (including fatalities) in pediatric patients; concomitant use of succinylcholine was associated with many of the reported cases, but not all. Risk of hyperkalemia is increased in pediatric patients with underlying neuromuscular disease (eg, Duchenne muscular dystrophy). Other abnormalities may include elevation in creatinine kinase (CK) and myoglobinuria. Monitor closely for hyperkalemic-associated arrhythmias; aggressively identify and treat.
• Hypersensitivity: Hypersensitivity reactions (eg, anaphylaxis, cardiovascular collapse, difficulty breathing, hypotension, rash) have been reported.
• Increased intracranial pressure: Dilates the cerebral vasculature and may, in certain conditions, increase intracranial pressure.
• Malignant hyperthermia: May trigger malignant hyperthermia; some reported cases have been fatal. Use is contraindicated in patients susceptible to malignant hyperthermia.
• Obstetrical anesthesia: Increased blood loss comparable with that seen with halothane has been reported during abortions.
• Respiratory depression: Causes dose-dependent respiratory depression and blunted ventilatory response to hypoxia and hypercapnia (Golembiewski 2004).
Disease-related concerns:
• Heart failure: In a scientific statement from the American Heart Association, isoflurane has been determined to be an agent that may exacerbate underlying myocardial dysfunction (magnitude: major) (AHA [Page 2016]).
• Hepatic impairment: Use with caution in patients with history of hepatic impairment or taking medications known to cause hepatic impairment; evaluate need for repeated exposure in a short time as clinically indicated.
Special populations:
• Pediatric neurotoxicity: In pediatric and neonatal patients <3 years and patients in third trimester of pregnancy (ie, times of rapid brain growth and synaptogenesis), the repeated or lengthy exposure to sedatives or anesthetics during surgery/procedures may have detrimental effects on child or fetal brain development and may contribute to various cognitive and behavioral problems. Epidemiological studies in humans have reported various cognitive and behavioral problems including neurodevelopmental delay (and related diagnoses), learning disabilities, and ADHD. Human clinical data suggest that single, relatively short exposures are not likely to have similar negative effects. No specific anesthetic/sedative has been found to be safer. For elective procedures, risk vs benefits should be evaluated and discussed with parents/caregivers/patients; critical surgeries should not be delayed.
Special handling:
• Occupational caution: There is no specific work exposure limit established for isoflurane. However, the National Institute for Occupational Safety and Health (NIOSH) recommends no worker be exposed to >2 ppm (ceiling concentrations) over a period of 1 hour. Precautions (eg, adequate ventilation, scavenging-systems, minimizing leaks/spills) can help to lessen any potential risk.
Other warnings/precautions:
• Desiccated absorbents: Reaction of isoflurane with desiccated CO2 absorbents produce carbon monoxide, which may result in elevated carboxyhemoglobin levels in some patients.
Substrate of CYP2E1 (minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential
Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Risk C: Monitor therapy
Alfuzosin: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Alizapride: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Amifostine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Amifostine. Management: When used at chemotherapy doses, hold blood pressure lowering medications for 24 hours before amifostine administration. If blood pressure lowering therapy cannot be held, do not administer amifostine. Use caution with radiotherapy doses of amifostine. Risk D: Consider therapy modification
Amisulpride (Oral): May enhance the hypotensive effect of Hypotension-Associated Agents. Risk C: Monitor therapy
Antipsychotic Agents (Second Generation [Atypical]): Blood Pressure Lowering Agents may enhance the hypotensive effect of Antipsychotic Agents (Second Generation [Atypical]). Risk C: Monitor therapy
Azelastine (Nasal): May enhance the CNS depressant effect of CNS Depressants. Risk X: Avoid combination
Bambuterol: May enhance the arrhythmogenic effect of Inhalational Anesthetics. Management: Some labels recommend specifically avoiding halothane; others recommend separating administration by at least 6 hours; other bambuterol labels do not mention this possible interaction. Monitor for increased sensitivity to arrhythmias if coadministered. Risk D: Consider therapy modification
Barbiturates: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Benperidol: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Blonanserin: CNS Depressants may enhance the CNS depressant effect of Blonanserin. Management: Use caution if coadministering blonanserin and CNS depressants; dose reduction of the other CNS depressant may be required. Strong CNS depressants should not be coadministered with blonanserin. Risk D: Consider therapy modification
Blood Pressure Lowering Agents: May enhance the hypotensive effect of Hypotension-Associated Agents. Risk C: Monitor therapy
Brexanolone: CNS Depressants may enhance the CNS depressant effect of Brexanolone. Risk C: Monitor therapy
Brimonidine (Topical): May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Brimonidine (Topical): May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Bromopride: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Bromperidol: May diminish the hypotensive effect of Blood Pressure Lowering Agents. Blood Pressure Lowering Agents may enhance the hypotensive effect of Bromperidol. Risk X: Avoid combination
Bromperidol: May enhance the CNS depressant effect of CNS Depressants. Risk X: Avoid combination
Buprenorphine: CNS Depressants may enhance the CNS depressant effect of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine at lower doses in patients already receiving CNS depressants. Risk D: Consider therapy modification
Cannabinoid-Containing Products: CNS Depressants may enhance the CNS depressant effect of Cannabinoid-Containing Products. Risk C: Monitor therapy
Chlormethiazole: May enhance the CNS depressant effect of CNS Depressants. Management: Monitor closely for evidence of excessive CNS depression. The chlormethiazole labeling states that an appropriately reduced dose should be used if such a combination must be used. Risk D: Consider therapy modification
Chlorphenesin Carbamate: May enhance the adverse/toxic effect of CNS Depressants. Risk C: Monitor therapy
CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Risk C: Monitor therapy
Daridorexant: May enhance the CNS depressant effect of CNS Depressants. Management: Dose reduction of daridorexant and/or any other CNS depressant may be necessary. Use of daridorexant with alcohol is not recommended, and the use of daridorexant with any other drug to treat insomnia is not recommended. Risk D: Consider therapy modification
Dexmethylphenidate-Methylphenidate: May enhance the hypertensive effect of Inhalational Anesthetics. Risk X: Avoid combination
Diazoxide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Difelikefalin: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Dimethindene (Topical): May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
DOPamine: Inhalational Anesthetics may enhance the arrhythmogenic effect of DOPamine. Management: Avoid use of dopamine in patients receiving halogenated hydrocarbon anesthetics. If concomitant treatment cannot be avoided, monitor for arrhythmia. Dopamine induced ventricular arrhythmia may be reversible with propranolol based on animal data. Risk X: Avoid combination
Doxylamine: May enhance the CNS depressant effect of CNS Depressants. Management: The manufacturer of Diclegis (doxylamine/pyridoxine), intended for use in pregnancy, specifically states that use with other CNS depressants is not recommended. Risk C: Monitor therapy
Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (eg, opioids, barbiturates) with concomitant use. Risk D: Consider therapy modification
DULoxetine: Blood Pressure Lowering Agents may enhance the hypotensive effect of DULoxetine. Risk C: Monitor therapy
Ephedra: May enhance the arrhythmogenic effect of Inhalational Anesthetics. Risk X: Avoid combination
EPHEDrine (Nasal): May enhance the arrhythmogenic effect of Inhalational Anesthetics. Risk X: Avoid combination
EPHEDrine (Systemic): May enhance the arrhythmogenic effect of Inhalational Anesthetics. Risk X: Avoid combination
EPINEPHrine (Nasal): Inhalational Anesthetics may enhance the arrhythmogenic effect of EPINEPHrine (Nasal). Risk C: Monitor therapy
EPINEPHrine (Oral Inhalation): Inhalational Anesthetics may enhance the arrhythmogenic effect of EPINEPHrine (Oral Inhalation). Risk C: Monitor therapy
EPINEPHrine (Systemic): Inhalational Anesthetics may enhance the arrhythmogenic effect of EPINEPHrine (Systemic). Management: Administer epinephrine with added caution in patients receiving, or who have recently received, inhalational anesthetics. Use lower than normal doses of epinephrine and monitor for the development of cardiac arrhythmias. Risk D: Consider therapy modification
Esketamine: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Fenoterol: Inhalational Anesthetics may enhance the arrhythmogenic effect of Fenoterol. Risk C: Monitor therapy
Flunitrazepam: CNS Depressants may enhance the CNS depressant effect of Flunitrazepam. Management: Reduce the dose of CNS depressants when combined with flunitrazepam and monitor patients for evidence of CNS depression (eg, sedation, respiratory depression). Use non-CNS depressant alternatives when available. Risk D: Consider therapy modification
Formoterol: Inhalational Anesthetics may enhance the arrhythmogenic effect of Formoterol. Risk C: Monitor therapy
Haloperidol: QT-prolonging Agents (Indeterminate Risk - Caution) may enhance the QTc-prolonging effect of Haloperidol. Risk C: Monitor therapy
Herbal Products with Blood Pressure Lowering Effects: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
HydrOXYzine: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Hypotension-Associated Agents: Blood Pressure Lowering Agents may enhance the hypotensive effect of Hypotension-Associated Agents. Risk C: Monitor therapy
Isoproterenol: Inhalational Anesthetics may enhance the arrhythmogenic effect of Isoproterenol. Risk X: Avoid combination
Kava Kava: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Kratom: May enhance the CNS depressant effect of CNS Depressants. Risk X: Avoid combination
Lemborexant: May enhance the CNS depressant effect of CNS Depressants. Management: Dosage adjustments of lemborexant and of concomitant CNS depressants may be necessary when administered together because of potentially additive CNS depressant effects. Close monitoring for CNS depressant effects is necessary. Risk D: Consider therapy modification
Levodopa-Containing Products: Blood Pressure Lowering Agents may enhance the hypotensive effect of Levodopa-Containing Products. Risk C: Monitor therapy
Lisuride: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Lofexidine: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Lormetazepam: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Metaraminol: Inhalational Anesthetics may enhance the arrhythmogenic effect of Metaraminol. Risk X: Avoid combination
Methotrimeprazine: CNS Depressants may enhance the CNS depressant effect of Methotrimeprazine. Methotrimeprazine may enhance the CNS depressant effect of CNS Depressants. Management: Reduce the usual dose of CNS depressants by 50% if starting methotrimeprazine until the dose of methotrimeprazine is stable. Monitor patient closely for evidence of CNS depression. Risk D: Consider therapy modification
Metoclopramide: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
MetyroSINE: CNS Depressants may enhance the sedative effect of MetyroSINE. Risk C: Monitor therapy
Minocycline (Systemic): May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Molsidomine: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Naftopidil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Neuromuscular-Blocking Agents: Isoflurane may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Risk C: Monitor therapy
Neuromuscular-Blocking Agents (Nondepolarizing): Inhalational Anesthetics may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents (Nondepolarizing). Management: When initiating a non-depolarizing neuromuscular blocking agent (NMBA) in a patient receiving an inhalational anesthetic, initial NMBA doses should be reduced 15% to 25% and doses of continuous infusions should be reduced 30% to 60%. Risk D: Consider therapy modification
Nicergoline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Nicorandil: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Nitroprusside: Blood Pressure Lowering Agents may enhance the hypotensive effect of Nitroprusside. Risk C: Monitor therapy
Nitrous Oxide: Isoflurane may enhance the CNS depressant effect of Nitrous Oxide. Nitrous Oxide may enhance the therapeutic effect of Isoflurane. Specifically, isoflurane MAC values may be decreased. Risk C: Monitor therapy
Norepinephrine: Inhalational Anesthetics may enhance the arrhythmogenic effect of Norepinephrine. Risk C: Monitor therapy
Obinutuzumab: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Management: Consider temporarily withholding blood pressure lowering medications beginning 12 hours prior to obinutuzumab infusion and continuing until 1 hour after the end of the infusion. Risk D: Consider therapy modification
Olopatadine (Nasal): May enhance the CNS depressant effect of CNS Depressants. Risk X: Avoid combination
Opioid Agonists: CNS Depressants may enhance the CNS depressant effect of Opioid Agonists. Management: Avoid concomitant use of opioid agonists and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Risk D: Consider therapy modification
Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Risk X: Avoid combination
Oxomemazine: May enhance the CNS depressant effect of CNS Depressants. Risk X: Avoid combination
Oxybate Salt Products: CNS Depressants may enhance the CNS depressant effect of Oxybate Salt Products. Management: Consider alternatives to this combination when possible. If combined, dose reduction or discontinuation of one or more CNS depressants (including the oxybate salt product) should be considered. Interrupt oxybate salt treatment during short-term opioid use Risk D: Consider therapy modification
OxyCODONE: CNS Depressants may enhance the CNS depressant effect of OxyCODONE. Management: Avoid concomitant use of oxycodone and benzodiazepines or other CNS depressants when possible. These agents should only be combined if alternative treatment options are inadequate. If combined, limit the dosages and duration of each drug. Risk D: Consider therapy modification
Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Risk X: Avoid combination
Pentoxifylline: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Perampanel: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Pholcodine: Blood Pressure Lowering Agents may enhance the hypotensive effect of Pholcodine. Risk C: Monitor therapy
Phosphodiesterase 5 Inhibitors: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Piribedil: CNS Depressants may enhance the CNS depressant effect of Piribedil. Risk C: Monitor therapy
Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Risk C: Monitor therapy
Prostacyclin Analogues: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
QT-prolonging Agents (Highest Risk): QT-prolonging Agents (Indeterminate Risk - Caution) may enhance the QTc-prolonging effect of QT-prolonging Agents (Highest Risk). Management: Monitor for QTc interval prolongation and ventricular arrhythmias when these agents are combined. Patients with additional risk factors for QTc prolongation may be at even higher risk. Risk C: Monitor therapy
Quinagolide: May enhance the hypotensive effect of Blood Pressure Lowering Agents. Risk C: Monitor therapy
Ritodrine: May enhance the adverse/toxic effect of Inhalational Anesthetics. Risk C: Monitor therapy
Ropeginterferon Alfa-2b: CNS Depressants may enhance the adverse/toxic effect of Ropeginterferon Alfa-2b. Specifically, the risk of neuropsychiatric adverse effects may be increased. Management: Avoid coadministration of ropeginterferon alfa-2b and other CNS depressants. If this combination cannot be avoided, monitor patients for neuropsychiatric adverse effects (eg, depression, suicidal ideation, aggression, mania). Risk D: Consider therapy modification
ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Risk C: Monitor therapy
Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Risk C: Monitor therapy
Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Risk C: Monitor therapy
Suvorexant: CNS Depressants may enhance the CNS depressant effect of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Risk D: Consider therapy modification
Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Risk X: Avoid combination
Trimeprazine: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Valerian: May enhance the CNS depressant effect of CNS Depressants. Risk C: Monitor therapy
Zolpidem: CNS Depressants may enhance the CNS depressant effect of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Risk D: Consider therapy modification
Isoflurane crosses the placenta (Dwyer 1995; Satoh 1995).
Based on animal data, repeated or prolonged use of general anesthetic and sedation medications that block N-methyl-D- aspartate (NMDA) receptors and/or potentiate gamma-aminobutyric acid (GABA) activity, may affect brain development. Evaluate benefits and potential risks of fetal exposure to isoflurane when duration of surgery is expected to be >3 hours (Olutoye 2018).
Use of isoflurane in obstetric anesthesia has been described (Abboud 1989; ACOG 209 2019; Devroe 2015; Ghaly 1988; Liu 2013). Maternal exposure should be minimized due to dose dependent uterine relaxation and fetal depression (ACOG 209 2019; Devroe 2015).
The ACOG recommends that pregnant women should not be denied medically necessary surgery, regardless of trimester. If the procedure is elective, it should be delayed until after delivery (ACOG 775 2019).
It is not known if isoflurane is present in breast milk.
The manufacturer recommends that caution be exercised when administering isoflurane to breastfeeding women.
Based on pharmacokinetic properties, use of isoflurane in breastfeeding women may be considered acceptable (Lee 1993). The Academy of Breast Feeding Medicine recommends postponing elective surgery until milk supply and breastfeeding are established. Milk should be expressed ahead of surgery when possible. In general, when the child is healthy and full term, breastfeeding may resume, or milk may be expressed once the mother is awake and in recovery. For children who are at risk for apnea, hypotension, or hypotonia, milk may be saved for later use when the child is at lower risk (ABM [Reece-Stremtan 2017]).
BP, electrocardiogram, serum potassium, oxygen saturation, respiration, end-tidal CO2 and isoflurane concentrations should be monitored prior to and throughout anesthesia; consider additional cardiac monitoring in patients with coronary artery disease; QT interval in patients at risk for QTc prolongation.
Isoflurane is a general anesthetic agent capable of producing profound respiratory depression. Inhaled anesthetics alter activity of neuronal ion channels, particularly the fast synaptic neurotransmitter receptors (nicotinic acetylcholine, gamma-aminobutyric acid [GABA], and glutamate receptors). May depress myocardial contractility, decrease blood pressure through a decrease in systemic vascular resistance, and decrease sympathetic nervous activity (Stachnik 2006).
Metabolism: Minimally hepatic (<0.2%), predominantly CYP2E1 (Golembiewski 2004)
Excretion: Exhaled gases