ETHRANE
Clinical safety rating
cautionComprehensive clinical and safety monograph for ETHRANE (ETHRANE).
Enflurane is a volatile inhalational anesthetic that potentiates GABA-A receptor activity and inhibits excitatory neurotransmission, resulting in general anesthesia.
| Metabolism | Primarily hepatic via cytochrome P450 (CYP2E1); minor metabolism to fluoride ions. |
| Excretion | Primarily exhaled unchanged via lungs (>95%); less than 5% metabolized in liver to fluoride ion and other metabolites, with renal excretion of metabolites. |
| Half-life | Context-sensitive half-life: approximately 2-5 minutes after short procedures; prolonged after prolonged administration due to slow washout from fat stores. |
| Protein binding | Approximately 30-40%, primarily to albumin. |
| Volume of Distribution | Vd: 1.2-2.0 L/kg, indicating extensive distribution into tissues, especially fat. |
| Bioavailability | By inhalation: 100% as delivered; not administered orally. |
| Onset of Action | Inhalation: induction within 2-4 minutes with gradual dose increase. |
| Duration of Action | Recovery from anesthesia: 5-15 minutes after discontinuation; rapid due to low blood-gas partition coefficient. |
| Molecular Weight | 184.5 |
1-5% inspired concentration via inhalation, titrated to effect for maintenance of general anesthesia.
| Dosage form | LIQUID |
| Renal impairment | No dose adjustment required for GFR >10 mL/min; use with caution in severe renal impairment (GFR <10 mL/min) due to potential accumulation of inorganic fluoride metabolites. |
| Liver impairment | No specific Child-Pugh based adjustment; use with caution in severe hepatic impairment as metabolism may be decreased. |
| Pediatric use | Induction: 2-5% inspired concentration; Maintenance: 1-3% inspired concentration, adjusted to age and response. |
| Geriatric use | Lower inspired concentrations (0.5-2%) recommended due to increased sensitivity and reduced clearance; titrate to effect. |
| 1st trimester | Avoid elective use; teratogenic effects observed in animal studies. |
| 2nd trimester | Use only if clearly needed; may cause fetal depression. |
| 3rd trimester | Use with caution; risk of uterine atony and neonatal depression. |
Clinical note
Comprehensive clinical and safety monograph for ETHRANE (ETHRANE).
| Placental transfer | Rapidly crosses placenta; fetal concentrations approach maternal levels. |
| Breastfeeding | Minimal excretion into breast milk; use with caution due to potential neonatal sedation. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | FDA Category B. No evidence of teratogenicity in animal studies; human data limited. Use only if clearly needed during pregnancy, especially first trimester due to potential fetal hypoxia from maternal hypotension. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, oxygen saturation, and end-tidal anesthetic concentration. Fetal heart rate monitoring if applicable; adjust anesthetic depth to avoid maternal hypotension and fetal hypoxia. |
| Fertility Effects | No significant effects on fertility reported. Occupational exposure to waste anesthetic gases may pose reproductive risks; use scavenging systems. |
■ FDA Black Box Warning
None
| Serious Effects |
Known hypersensitivity to halogenated anestheticsKnown or suspected malignant hyperthermia susceptibilityConcurrent use of potent analgesics with respiratory depressant effects
| Precautions | May cause dose-dependent cardiovascular depression, Risk of malignant hyperthermia, Potential for nephrotoxicity due to fluoride release, Hepatotoxicity risk, especially with repeated use, Neurologic effects including seizure activity at high doses |
| Food/Dietary | No specific food interactions. Patient must follow preoperative fasting guidelines (nil per os, NPO) as directed by anesthesiologist to reduce risk of aspiration. |
| Clinical Pearls | ETHRANE (enflurane) is a potent inhalation anesthetic. Its use is limited due to risk of seizures at high doses and potential for nephrotoxicity from fluoride ion release. Avoid in patients with history of seizures or renal impairment. Rapid induction and recovery; use with caution in hypotensive patients due to myocardial depression. Malignant hyperthermia trigger. |
| Patient Advice | You will receive this anesthesia medication only in a hospital setting under expert supervision. · Possible side effects include nausea, vomiting, shivering, and confusion after waking up. · Tell your doctor if you have a history of seizures, kidney problems, or muscle disorders. · Avoid driving or operating machinery for at least 24 hours after anesthesia. · Do not eat or drink for the time specified by your healthcare team before surgery. |
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