Isoflurane
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From MedlinePlus, U.S. National Library of Medicine
General Anesthetic
Dosing in kidney impairment
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. If malignant hyperthermia is suspected, discontinue all triggering agents (i.e., volatile anesthetic agents and succinylcholine), administer intravenous dantrolene sodium, and initiate supportive therapies.
Preparation and administration
Important Dosage and Administration Information FORANE 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. FORANE is administered by inhalation.
FORANE should be delivered from a vaporizer specifically designed for use with FORANE. 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 FORANE (see Table 1 ). Opioids decrease the MAC of FORANE [see Drug Interactions ] . FORANE potentiates the muscle relaxant effect of all neuromuscular blockers and decreases the required doses of neuromuscular blocking agents [see Drug Interactions ] . The dose should be adjusted accordingly.
All patients anesthetized with FORANE should be continually monitored (e.g., monitoring of the electrocardiogram, blood pressure, oxygen saturation, and end tidal CO2). FORANE is a profound respiratory depressant. Excessive respiratory depression may be related to depth of anesthesia and respond to decreasing the inspired concentration of FORANE.
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.
| Age | Average MAC Value In 100% Oxygen | Average MAC Value In 30% Oxygen and 70% N2 O |
| Preterm neonates less than 32 weeks gestational age | 1.28% | |
| Preterm neonates 32-37 weeks gestational age | 1.41% | |
| 0-1 month | 1.60% | |
| 1-6 months | 1.87% | |
| 6-12 months | 1.80% | |
| 1-5 years | 1.60% | |
| 6-10 years | 1.45% | |
| 11-18 years | 1.38% | |
| 19-30 years | 1.28% | 0.56% |
| 31-55 years | 1.15% | 0.50% |
| 55-83 years | 1.05% | 0.37% |
Drug interactions
Check isoflurane against a medication listLabel text (8 paragraphs)
7 DRUG INTERACTIONS • Concomitant use of N 2 O and/or opioids reduces the MAC of FORANE. Adjust dose accordingly. ( 7.1 , 7.2 ) • FORANE decreases the doses of neuromuscular blocking agents required. Adjust dose accordingly. ( 7.3 )
7.1 Opioids Opioids decrease the Minimum Alveolar Concentration (MAC) of FORANE. Opioids such as fentanyl and its analogues, when combined with FORANE, may lead to a synergistic fall in blood pressure and respiratory rate.
7.2 Nitrous Oxide Nitrous oxide decreases the MAC of FORANE [see Dosage and Administration (2.1) ] .
7.3 Neuromuscular Blocking Agents FORANE potentiates the muscle relaxant effect of all neuromuscular blocking agents and decreases the required doses of neuromuscular blocking agents. In general, anesthetic concentrations of FORANE at equilibrium reduce the ED 95 of succinylcholine, atracurium, pancuronium, rocuronium and vecuronium by approximately 25 to 40% or more compared to N 2 O/opioid anesthesia. If added relaxation is required, supplemental doses of neuromuscular blocking agents may be used.
7.4 Adrenaline FORANE is similar to sevoflurane in the sensitization of the myocardium to arrhythmogenic effect of exogenously administered adrenaline. Doses of adrenaline greater than 5mcg/kg, when administered submucosally may produce multiple ventricular arrhythmias.
7.5 Calcium Antagonists FORANE may lead to marked hypotension in patients treated with calcium antagonists.
7.6 Concomitant Use with Beta Blockers Concomitant use of beta blockers may exaggerate the cardiovascular effects of inhalational anesthetics, including hypotension and negative inotropic effects.
7.7 Concomitant Use with MAO Inhibitors Concomitant use of MAO inhibitors and inhalational anesthetics may increase the risk of hemodynamic instability during surgery or medical procedures.
Contraindications
4 CONTRAINDICATIONS FORANE is contraindicated in patients: • in whom general anesthesia is contraindicated. • with known sensitivity to FORANE or to other halogenated agents [see Warnings and Precautions (5.3) ] . • with known or suspected genetic susceptibility to malignant hyperthermia [see Warnings and Precautions (5.1) , Clinical Pharmacology (12.5) ] . • with a history of confirmed hepatitis due to a halogenated inhalational anesthetic or a history of unexplained moderate to severe hepatic dysfunction (e.g., jaundice associated with fever and/or eosinophilia) after anesthesia with isoflurane or other halogenated inhalational anesthetics.
• Patients in whom general anesthesia is contraindicated ( 4 ) • Patients with known sensitivity to FORANE or other halogenated agents ( 4 ) • Patients with known or suspected genetic susceptibility to malignant hyperthermia ( 4 ) • Patients with a history of confirmed hepatitis due to a halogenated inhalational anesthetic or a history of unexplained moderate to severe hepatic dysfunction (e.g., jaundice associated with fever and/or eosinophilia) after anesthesia with FORANE or other halogenated inhalational anesthetics ( 4 )
Safety data
Reported adverse events (FAERS)
Liver injury (LiverTox)
BLikelihood score B: Highly likely cause of clinically apparent liver injury.
Isoflurane is a commonly used inhalational anesthetic and has an excellent safety record. Isoflurane has been linked to rare instances of severe acute liver injury resembling halothane induced liver injury in small case series and individual case reports.
ABCDEA: well known cause; E: unlikely cause. [HD]: high doses only.
Pregnancy and lactation
Pregnancy
8.1 Pregnancy Risk Summary There are no adequate and well-controlled studies in pregnant women. In animal reproduction studies, embryofetal toxicity was noted in pregnant mice exposed to 0.075% (increased post implantation losses) and 0.3% isoflurane (increased post implantation losses and decreased livebirth index) during organogenesis. Published studies in pregnant primates demonstrate that the administration of anesthetic and sedation drugs that block NMDA receptors and/or potentiate GABA activity during the period of peak brain development increases neuronal apoptosis in the developing brain of the offspring when used for longer than 3 hours.
There are no data on pregnancy exposures in primates corresponding to periods prior to the third trimester in humans (see Data). The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. Data Animal Data Pregnant rats were exposed to isoflurane at concentrations of 0%, 0.1%, or 0.4% for two hours per day during organogenesis (Gestational Days 6-15).
Isoflurane did not cause malformations or clear maternal toxicity under these conditions. Pregnant mice exposed to isoflurane at concentrations of 0%, 0.075%, or 0.30% for 2 hours per day during organogenesis (Gestational Days 6-15). Isoflurane increased fetal toxicity (higher post implantation losses at 0.075 and 0.3% groups and significantly lower live-birth index in the 0.3% isoflurane treatment group). Isoflurane did not cause malformations or clear maternal toxicity under these conditions. Pregnant rats were exposed to concentrations of isoflurane at 0%, 0.1%, or 0.4% for 2 hours per day during late gestation (GD 15-20). Animals appeared slightly sedated during exposure.
No adverse effects on the offspring or evidence of maternal toxicity were reported. This study did not evaluate neurobehavioral function including learning and memory in the first generation (F1) of pups. In a published study in primates, administration of an anesthetic dose of ketamine for 24 hours on Gestation Day 122 increased neuronal apoptosis in the developing brain of the fetus. In other published studies, administration of either isoflurane or propofol for 5 hours on Gestation Day 120 resulted in increased neuronal and oligodendrocyte apoptosis in the developing brain of the…
Breastfeeding (LactMed)
There is no published experience with isoflurane during breastfeeding. Because the serum half-life of isoflurane in the mother is short and the drug is not expected to be absorbed by the infant, no waiting period or discarding of milk is required. Breastfeeding can be resumed as soon as the mother has recovered sufficiently from general anesthesia to nurse. When a combination of anesthetic agents is used for a procedure, follow the recommendations for the most problematic medication used during the procedure. In one study, breastfeeding before general anesthesia induction reduced requirements of sevoflurane and propofol compared to those of nursing mothers whose breastfeeding was withheld or nonnursing women. It is possible that requirements for other anesthetic agents would be affected similarly.
- Desflurane
- Enflurane
- Sevoflurane
Supply and cost
Drug shortage status
Recalls (last 24 months)
Therapeutic equivalence (Orange Book)
Price ladder
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