Isoflurane: Composition, Structure, Indications, Contraindications, Mechanism of Action, Interactions and Side Effects

It is the most recent halogenated anesthetic introduced in clinical practice (1983).

Isoflurane is an anesthetic by inhalation.


Chemically isoflurane is 2-chloro-2- (difluoromethoxy) -1,1,1-trifluoroethane. Isoflurane is an isomer of enflurane.

Isoflurane is not flammable or explosive. Isoflurane is a racemic mixture and is prepared by chemical synthesis.

Inhaled gases are the basis of anesthesia and are used primarily to maintain anesthesia after administering an intravenous agent. The depth of anesthesia can be altered rapidly by changing the concentration of inhaled anesthetic.

Most agents are rapidly eliminated from the body and do not cause postoperative respiratory depression.

Molecular structure

It is of synthetic origin and belongs to the general group of Volatile Anesthetic Drugs based on the mechanism of action and is also classified in the broad pharmacological group of Anesthetics. The molecular weight of isoflurane is 184.50.



Isoflurane is indicated mainly in conditions such as induction and maintenance of anesthesia.


Isoflurane is contraindicated in diseases such as coronary artery disease, susceptibility to malignant hyperthermia, and neurological procedures.

Mechanism of action

Isoflurane induces a reduction in the binding conductance by decreasing the opening times of the gap junction channel and increasing the closing times of the gap junction channel.

Isoflurane also activates calcium-dependent ATPase in the sarcoplasmic reticulum by increasing the fluidity of the lipid membrane.

It also appears to bind to the D subunit of ATP synthase and NADH dehydrogenase. Isoflurane also binds to the GABA receptor, the high conductance Ca 2+ activated potassium channel, the glutamate receptor, and the glycine receptor.

Drug interactions

It is known that isoflurane interacts with other drugs; the details of the interactions between drugs are the following:

  • Adrenalin.
  • Atracurium (Besylate).
  • Doxapram.
  • Mivacurium (Cl).
  • Nitric oxide.
  • Nitrous oxide.
  • Pancuronium (Br).
  • Propofol.

It can be expected that propofol isoflurane increases the anesthetic or sedative and cardiorespiratory effects of the injectable propofol emulsion.

Side effects

Serious or irreversible adverse effects of isoflurane, which give rise to additional complications, include:

  • Hepatitis.
  • Cardiovascular collapse

Isoflurane produces life-threatening effects that include:

These effects are responsible for the interruption of therapy with isoflurane.

Signs and symptoms after acute isoflurane overdose include depression of vital functions.

Symptomatic adverse reactions produced by isoflurane are more or less tolerable, and if they become severe, they can be treated symptomatically, such as nausea, vomiting, and chills.

High-risk groups

The medication must not be administered to:

  • Pregnant mothers.
  • Cardiac/hypertensive patients.
  • Geriatric
  • Neonates

If the prescribing authority justifies the benefits of the medication against possible harm, it must re-evaluate them and consult the reference material and previous studies.

Warning and precautions

Avoid the use of isoflurane in patients who are susceptible to malignant hyperthermia. Patients should exercise caution when driving or performing other tasks that require alertness, as they may cause drowsiness.

Patients with chronic diseases such as diabetes or hypertension may require adjusting their therapy before anesthesia.

Anesthetics should be administered with caution in patients with heart, respiratory, renal, or hepatic insufficiency. Avoid use during pregnancy.

Isoflurane should be used with caution in patients with pheochromocytoma or elevated intracranial pressure.

The use of isoflurane in the patient with myasthenia gravis may cause an increase in muscle weakness due to the neuromuscular-blocking effect of the anesthetics.

The drug should be used with caution during pregnancy and lactation.

Storage conditions

Store in a tightly-closed container, at room temperature, between 15 ° C-30 ° C. Protect from sunlight and heat.