Enflurane

Name: Enflurane

Uses of Enflurane

Enflurane is used in the treatment of:

  • Status Asthmaticus
  • Ventricular Premature Complexes

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Enflurane Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • ENFLURANE/ISONIAZID
  • ENFLURANE/LABETALOL
  • ENFLURANE/SODIUM OXYBATE

This is not a complete list of Enfluranedrug interactions. Ask your doctor or pharmacist for more information.

Enflurane Dosage

Take enflurane exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The Enflurane dose your doctor recommends will be based on the following (use any or all that apply):

  • the condition being treated
  • other medical conditions you have
  • other medications you are taking
  • how you respond to this medication
  • your weight
  • your height
  • your age
  • your gender

Enflurane is available in the following doses:

  • Enflurane 100% Inhalation Solution

Enflurane - Clinical Pharmacology


Enflurane is an inhalation anesthetic. The MAC (minimum alveolar concentration) in man is 1.68% in pure oxygen, 0.57 in 70% nitrous oxide, 30% oxygen, and 1.17 in 30% nitrous oxide, 70% oxygen.Induction of and recovery from anesthesia with Enflurane are rapid. Enflurane has a mild sweet odor. Enflurane may provide a mild stimulus to salivation or tracheobronchial secretions. Pharyngeal and laryngeal reflexes are readily obtunded. The level of anesthesia can be changed rapidly by changing the inspired Enflurane concentration. Enflurane reduces ventilation as depth of anesthesia increases. High PaCO2 levels can be obtained at deeper levels of anesthesia if ventilation is not supported. Enflurane provokes a sigh response reminiscent of that seen with diethyl ether. There is a decrease in blood pressure with induction of anesthesia, followed by a return to near normal with surgical stimulation. Progressive increases in depth of anesthesia produce corresponding increases in hypotension. Heart rate remains relatively constant without significant bradycardia. Electrocardiographic monitoring or recordings indicate that cardiac rhythm remains stable. Elevation of the carbon dioxide level in arterial blood does not alter cardiac rhythm.

Studies in man indicate a considerable margin of safety in the administration of Epinephrine containing solutions during Enflurane anesthesia. Enflurane anesthesia has been used in excision of pheochromocytoma in man without ventricular arrhythmias. On the basis of studies in patients anesthetized with Enflurane and injected with epinephrine-containing solutions to achieve hemostasis in a highly vascular area (transsphenoidal surgery), up to 2 micrograms per kilogram (2 μg/kg) of epinephrine may be injected subcutaneously over a 10 minute period in patients judged to have ordinary tolerance to epinephrine administration. This would represent up to 14 mL of 1:100,000 epinephrine-containing solution (10 μg/mL), or the equivalent quantity, in a 70 kilogram patient. This may be repeated up to 3 times per hour (total 42 mL per hour).The concomitant administration of lidocaine enhances the safety of the use of epinephrine during Enflurane anesthesia. This effect of lidocain is dose related.All customary precautions in the use of vasoconstrictor substances should be observed. Muscle relaxation may be adequate for intra-abdominal operations at normal levels of anesthesia.  Muscle relaxants may be used to achieve greater relaxation and all commonly used muscle relaxants are compatible with Enflurane. THE NONDEPOLARIZING MUSCLE RELAXANTS ARE POTENTIATED. In the normal 70 kg adult, 6 to 9 mg of d-tubocurarine or 1 to 1.5 mg of pancuronium will produce a 90% or greater depression of twitch height. Neostigmine does not reverse the direct effect of Enflurane.Enflurane 0.25 to 1% (average 0.5%) provides analgesia equal to that produced by 30 to 60% (average 40%) nitrous oxide for vaginal delivery. With either agent, patients remain awake, cooperative and oriented. Maternal blood losses are comparable. These clinical approaches produce normal Apgar scores. Serial neurobehavioral testing of the newborn during the first 24 hours of life reveals that neither Enflurane nor nitrous oxide analgesia is associated with obvious neurobehavioral alterations. Neither Enflurane nor nitrous oxide when used for obstetrical analgesia alters BUN, creatinine, uric acid or osmolality.The only difference in the use of these two agents for obstetrical analgesia appears to be higher inspired oxygen concentration that may be used with Enflurane. Analgetic doses of Enflurane, up to approximately 1.0%, do not significantly depress the rate or force of uterine contraction during labor and delivery. A slowing of the rate of uterine contraction and a diminution of the force of uterine contraction is noted between the administration of 1.0 to 2.0% delivered Enflurane; concentrations somewhere between 2.0 and 3.0% delivered Enflurane may abolish uterine contractions. Enflurane displaces the myometrial response curve to oxytocin so that at lower concentrations of Enflurane oxytocin will restore uterine contractions; however, as the dose of Enflurane progresses (somewhere between 1.5 and 3% delivered Enflurane) the response to oxytocin is diminished and then abolished. Uterine bleeding may be increased when Enflurane is used in higher concentrations for vaginal delivery or to facilitate delivery by Cesarean section; however, this has not been demonstrated within the recommended dosage range (see DOSAGE AND ADMINISTRATIONsection).
Mean estimated blood loss in patients anesthetized for therapeutic termination of pregnancy with 1.0% Enflurane in 70% nitrous oxide with oxygen is approximately twice that noted following therapeutic termination of pregnancy performed with the use of a local anesthetic technique (40 mL versus 20 mL).




PharmacokineticsBiotransformation of Enflurane in man results in low peak levels of serum fluoride averaging 15 μmol/L. These levels are well below the 50 μmol/L threshold level, which can produce minimal renal damage in normal subjects. However, patients chronically ingesting isoniazid or other hydrazine-containing compounds may metabolize greater amounts of Enflurane. Although no significant renal dysfunction
has been found thus far in such patients, peak serum fluoride levels can exceed 50 μmol/L, particularly when anesthesia goes beyond 2 MAC hours. Depression of lymphocyte transformation does notfollow prolonged Enflurane anesthesia in man in the absence of surgery. Thus Enflurane does not depress this aspect of the immune response.
 
 
 

Adverse Reactions


1. Malignant hyperthermia (see WARNINGS).
2. Motor activity exemplified by movements of various muscle groups and/or seizures may be encountered with deep levels of Enflurane anesthesia, or light levels with hypocapnia
3. Hypotension, respiratory depression and hypoxia have been reported.
4. Arrhythmias, shivering, nausea and vomiting have been reported.
5. Elevation of the white blood count has been observed
6. Mild, moderate and severe liver injury, including hepatic failure, may rarely follow anesthesia with Enflurane
Serum transaminases may be increased and histologic evidence of injury may be found. The histologic changes are neither unique nor consistent. In several of these cases, it has not been possible to exclude Enflurane as the cause or as a contributing cause to liver injury. The incidence of unexplained
hepatotoxicity following the administration of Enflurane is unknown, but it appears to be rare and not dose related. Enflurane has also been associated with perioperative hyperkalemia (see WARNINGS). There have been rare post-marketing reports of hepatic failure and hepatic necrosis associated with the use of potent volatile anesthetic agents, includingEnflurane. Due to the spontaneous nature of these reports, the actual incidence and  relationship of Enflurane to these events cannot be established with certainty

Enflurane Levels and Effects while Breastfeeding

Summary of Use during Lactation

There is no published experience with enflurane during breastfeeding. Because the serum half-life of enflurane 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.[1] Breastfeeding can be resumed as soon as the mother has recovered sufficiently from general anesthesia to nurse.[2] 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.[3] It is possible that requirements for other anesthetic agents would be affected similarly.

Drug Levels

Maternal Levels. Relevant published information was not found as of the revision date.

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Relevant published information was not found as of the revision date.

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

Alternate Drugs to Consider

Desflurane, Isoflurane, Sevoflurane

References

1. Lee JJ, Rubin AP. Breast feeding and anaesthesia. Anaesthesia. 1993;48:616-25. PMID: 8346780

2. Dalal PG, Bosak J, Berlin C. Safety of the breast-feeding infant after maternal anesthesia. Paediatr Anaesth. 2014;24:359-71. PMID: 24372776

3. Bhaskara B, Dayananda VP, Kannan S et al. Effect of breastfeeding on haemodynamics and consumption of propofol and sevoflurane: A state entropy guided comparative study. Indian J Anaesth. 2016;60:180-6. PMID: 27053781

Enflurane Identification

Substance Name

Enflurane

CAS Registry Number

13838-16-9

Drug Class

Anesthetics, Inhalation

Administrative Information

LactMed Record Number

614

Last Revision Date

20160426

Disclaimer

Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.

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