Which statement about methoxyflurane is NOT true?

Which statement about methoxyflurane is NOT true?

• A. It is the most potent inhalant with slow recovery and up to 50% retention.
• B. It is metabolized for elimination.
• C. It is rapidly eliminated with no tissue retention.
• D. It has high tissue retention.

Answer: (C)

The main idea here is how tissue solubility and metabolism shape the washout of an inhaled anesthetic. Methoxyflurane is highly soluble in tissues, so it dissolves into fat and other tissues and is released back into the bloodstream slowly as the inhaled concentration drops. This leads to slow recovery and retention of the drug in the body. A significant portion can be retained (up to about 50%), and part of the dose is metabolized, including pathways that produce fluoride ions, which is why toxicity concerns arise. Therefore, the statement that it is rapidly eliminated with no tissue retention is not true. In reality, it has high tissue retention and a slow elimination profile, with metabolism contributing to its elimination and potential toxicity.