Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
KETALAR vs ETHRANE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Noncompetitive NMDA receptor antagonist; inhibits glutamate activity, modulates opioid receptors, and interacts with other neurotransmitter systems.
Enflurane is a volatile inhalational anesthetic that potentiates GABA-A receptor activity and inhibits excitatory neurotransmission, resulting in general anesthesia.
Induction and maintenance of general anesthesia,Procedural sedation and analgesia,Treatment of refractory status epilepticus (off-label),Major depressive disorder with suicidal ideation (off-label)
Induction and maintenance of general anesthesia
1-4.5 mg/kg IV or 6.5-13 mg/kg IM for induction of anesthesia; 0.1-0.5 mg/kg/min IV infusion for maintenance.
1-5% inspired concentration via inhalation, titrated to effect for maintenance of general anesthesia.
Terminal elimination half-life: 2.5-3 hours (ketamine); norketamine: 12 hours. Clinical context: Short half-life facilitates rapid recovery, but context-sensitive half-life increases with infusion duration.
Context-sensitive half-life: approximately 2-5 minutes after short procedures; prolonged after prolonged administration due to slow washout from fat stores.
Primarily hepatic via N-demethylation by CYP3A4 and CYP2B6 to norketamine, then further metabolized via hydroxylation and conjugation.
Primarily hepatic via cytochrome P450 (CYP2E1); minor metabolism to fluoride ions.
Renal: 90% as metabolites (norketamine, dehydronorketamine); unchanged: 2-4%. Fecal: <3%.
Primarily exhaled unchanged via lungs (>95%); less than 5% metabolized in liver to fluoride ion and other metabolites, with renal excretion of metabolites.
12-50% primarily to albumin and alpha-1-acid glycoprotein.
Approximately 30-40%, primarily to albumin.
1-2 L/kg (large, indicating extensive tissue distribution). Highly lipophilic, crosses blood-brain barrier rapidly.
Vd: 1.2-2.0 L/kg, indicating extensive distribution into tissues, especially fat.
Oral: 16-24% (extensive first-pass metabolism); Intranasal: 45-50%; IM: 93%; Subcutaneous: 100%.
By inhalation: 100% as delivered; not administered orally.
No dose adjustment required for GFR >10 m L/min; for GFR <10 m L/min, consider dose reduction by 50% due to accumulation of active metabolite norketamine.
No dose adjustment required for GFR >10 m L/min; use with caution in severe renal impairment (GFR <10 m L/min) due to potential accumulation of inorganic fluoride metabolites.
Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: avoid use or use with extreme caution, reduce dose by 75%.
No specific Child-Pugh based adjustment; use with caution in severe hepatic impairment as metabolism may be decreased.
Induction: 1-2 mg/kg IV or 4-6 mg/kg IM; maintenance: 0.5-1 mg/kg IV boluses or 10-50 mcg/kg/min IV infusion. Titrate to effect.
Induction: 2-5% inspired concentration; Maintenance: 1-3% inspired concentration, adjusted to age and response.
Reduce initial dose by 50% (e.g., 0.5-2 mg/kg IV) and titrate slowly due to increased sensitivity and risk of delirium; consider lower infusion rates (0.1-0.3 mg/kg/min).
Lower inspired concentrations (0.5-2%) recommended due to increased sensitivity and reduced clearance; titrate to effect.
Hemodynamic instability (hypertension, tachycardia) and increased intracranial pressure; risk of emergent reactions (hallucinations, delirium); potential for abuse and dependence.
None
Monitor blood pressure and cardiac function; use with caution in patients with hypertension, heart failure, or increased intracranial pressure; emergence reactions may occur; laryngospasm risk; respiratory depression.
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
Hypersensitivity to ketamine; conditions where elevated blood pressure or intracranial pressure would be dangerous (e.g., severe hypertension, cerebral hemorrhage); severe coronary artery disease; history of psychotic disorders.
Known hypersensitivity to enflurane or other halogenated anesthetics,Known or suspected susceptibility to malignant hyperthermia,Severe hepatic impairment,Uncontrolled epilepsy
No specific food interactions; avoid alcohol for 24 hours due to additive CNS depression.
No specific food interactions. Patient must follow preoperative fasting guidelines (nil per os, NPO) as directed by anesthesiologist to reduce risk of aspiration.
First trimester: Limited human data; animal studies show no teratogenicity. Second/third trimester: Use only if clearly needed; may cause neonatal respiratory depression, hypotonia, and altered neurobehavior if used near delivery.
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.
Excreted into breast milk in low amounts; M/P ratio unknown. Use caution, especially with repeated doses or in neonates with hepatic impairment.
Excreted in breast milk in low amounts; M/P ratio not established. Consider benefits of breastfeeding vs. risk of infant exposure. Minimal systemic absorption in infant expected.
No specific dose adjustment required for pregnancy; consider reduced dose due to increased volume of distribution and clearance in late pregnancy. Use lowest effective dose.
No specific dose adjustments required for pregnancy; however, MAC decreases by approximately 30% during pregnancy due to hormonal changes and increased progesterone. Monitor depth of anesthesia closely.
Ketamine (Ketalar) produces dissociative anesthesia with potent analgesia. Onset of action is rapid (30 seconds IV, 5 minutes IM). Emergence reactions (hallucinations, delirium) can be mitigated with benzodiazepines. Contraindicated in patients with hypertension, aneurysms, or increased intracranial pressure due to sympathomimetic effects. Use with caution in patients with psychosis or thyroid disorders.
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.
You may experience vivid dreams or hallucinations as the medication wears off; this is common and can be reduced with other medications.,Do not drive, operate machinery, or make important decisions for at least 24 hours after receiving ketamine.,Avoid alcohol and other sedatives for 24 hours after administration.,Inform your healthcare provider if you have high blood pressure, heart disease, or a history of psychosis.
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.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about KETALAR vs ETHRANE, answered by our medical review team.
KETALAR is a General Anesthetic that works by Noncompetitive NMDA receptor antagonist; inhibits glutamate activity, modulates opioid receptors, and interacts with other neurotransmitter systems.. ETHRANE is a General Anesthetic that works by Enflurane is a volatile inhalational anesthetic that potentiates GABA-A receptor activity and inhibits excitatory neurotransmission, resulting in general anesthesia.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between KETALAR and ETHRANE depend on the specific clinical indication. These are both General Anesthetic agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of KETALAR is: 1-4.5 mg/kg IV or 6.5-13 mg/kg IM for induction of anesthesia; 0.1-0.5 mg/kg/min IV infusion for maintenance.. The standard adult dose of ETHRANE is: 1-5% inspired concentration via inhalation, titrated to effect for maintenance of general anesthesia.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between KETALAR and ETHRANE in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. KETALAR is classified as Category C. First trimester: Limited human data; animal studies show no teratogenicity. Second/third trimester: Use only if clearly needed; may cause neonatal respiratory depression, hypotonia. ETHRANE is classified as Category C. 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 . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.