What is the Difference Between Isoflurane and Sevoflurane

The key difference between isoflurane and sevoflurane is that isoflurane is more soluble in tissues, whereas sevoflurane is less soluble.

Isoflurane and sevoflurane are two types of anesthetic medications that are administered through inhalation. These are very important in different medical applications, such as surgeries. Isoflurane is an anesthetic compound that is sold under the brand name Forane while Sevoflurane is an inhalation anesthetic having a sweet smell.

1. Overview and Key Difference
2. What is Isoflurane
3. What is Sevoflurane
4. Isoflurane vs Sevoflurane in Tabular Form
5. Summary – Isoflurane vs Sevoflurane

What is Isoflurane?

Isoflurane is an anesthetic compound that is sold under the brand name Forane. It is useful in starting to maintain anesthesia, but it is not usually preferred to initiate anesthesia. This is because of the airway irritation that can occur as a side effect. Typically, the route of administration for isoflurane is inhalation. The chemical formula of isoflurane is C₃H₂ClF₅O. The molar mass is 184.49 g/mol. The side effects of this anesthetic include a reduction in the ability to breathe, low blood pressure, and irregular heartbeat. However, there can be some serious side effects as well, such as malignant hyperthermia and high blood potassium.

When considering the medical use of isoflurane, it is administered with air and pure oxygen and, often with nitrous oxide. Comparing its physical properties, this anesthetic can induce anesthesia more rapidly compared to halothane. However, the pungent nature of isoflurane can irritate the respiratory system, which negates the possible advantages that are given by the physical properties of isoflurane.

When considering the chemical properties of isoflurane, it has a boiling point of 48.5 degrees Celsius at 1 atm, and the density is 1.496 g/cm³. Moreover, it has a low water solubility that is around 13.5 mM, and the blood: gas partition coefficient can be given as 1.4. However, the oil: gas partition coefficient is comparatively higher, around 98. Further, this compound comes as a racemic mixture of the R isomer and S isomer. These are optical isomers. It is typically non-combustible, but it can give irritable and toxic fumes when they are exposed to flame.

What is Sevoflurane?

Sevoflurane is an inhalation anesthetic having a sweet smell. It is non-flammable and can be categorized as a highly fluorinated methyl isopropyl ether. It is used for the induction and maintenance of general anesthesia. This medication has the fastest onset rate, which is second only to desflurane. However, its offset can be faster compared to agents other than desflurane. The trade names for sevoflurane include Sojourn, Ultane, Sevorane, etc.

The metabolism of this compound occurs in the liver in the presence of CYP2E1. The metabolites of this metabolism include hexafluoroisopropanol. The elimination half-life of sevoflurane is in the range of 15 – 23 hours, and excretion occurs in the kidney. The chemical formula of sevoflurane is C₄H₃F₇O, and the molar mass is 200 g/mol approximately. The boiling point can be given as 58.5 degrees Celsius. The most common side effects of sevoflurane include nausea, vomiting, hypotension, agitation, and cough.

What is the Difference Between Isoflurane and Sevoflurane?

Isoflurane and sevoflurane are isomers of each other. Both these are useful as anesthetic medications, but they have some differences between them as well. The key difference between isoflurane and sevoflurane is that isoflurane is more soluble in tissues, whereas sevoflurane is less soluble.

The below infographic presents the differences between isoflurane and sevoflurane in tabular form for side-by-side comparison.

Summary – Isoflurane vs Sevoflurane

Isoflurane is an anesthetic compound that is sold under the brand name Forane while Sevoflurane is an inhalation anesthetic having a sweet smell. The key difference between isoflurane and sevoflurane is that isoflurane is more soluble in tissues, whereas sevoflurane is less soluble.

Reference:

1. “Sevoflurane.” National Center for Biotechnology Information. PubChem Compound Database, U.S. National Library of Medicine.

Image Courtesy:

1. “Isoflurane” By Benrr101 – Own work (Public Domain) via Commons Wikimedia
2. “Sevoflurane” By Benrr101 – Own work (Public Domain) via Commons Wikimedia