Question 1

Q: Which is correct about the anesthetic drugs X and Y in the image shown? (Recent NEET Pattern 2016-17)

Drug X is more fast acting than Y. ***Drug X is more fast acting than Y*** - The **oil:gas partition coefficient** for Drug X is lower than for Drug Y. A lower oil:gas partition coefficient typically correlates with a **faster onset of action** for inhaled anesthetics as it indicates lower solubility in blood and tissues, allowing for quicker equilibration in the brain. - While MAC is plotted against oil:gas partition coefficient, the question specifically asks about **onset of action**, which is primarily influenced by blood-gas solubility rather than oil-gas solubility. However, an anesthetic with lower oil-gas solubility (like X) would generally also have lower blood-gas solubility, leading to faster onset. *Drug Y is more fast acting than X* - Drug Y has a **higher oil:gas partition coefficient** compared to Drug X, indicating greater lipid solubility. - A higher oil:gas partition coefficient generally correlates with a **slower onset of action** for inhaled anesthetics, as more drug dissolves in lipids before reaching the brain. *Drug X and Y have equally fast onset of action* - The graph clearly shows that Drug X and Drug Y have different **oil:gas partition coefficients**. - Since the partition coefficients are different, their **solubility characteristics** and therefore their clinical onset of action would also be different. *Drug X and Y have equally fast onset of action but potency of X is more than Y* - Onset of action is **not equal** for X and Y due to their differing oil:gas partition coefficients. - Potency, represented by **MAC** (Minimum Alveolar Concentration), is inversely related to the oil:gas partition coefficient for many inhaled anesthetics. From the graph, Drug X has a higher MAC value than Drug Y (meaning it is **less potent** but acts faster).

Question

Which is correct about the anesthetic drugs X and Y in the image shown? (Recent NEET Pattern 2016-17)

Accepted Answer

Drug X is more fast acting than Y

Answer

Drug X and Y have equally fast onset of action

Answer

Drug X and Y have equally fast onset of action but potency of X is more than Y

Answer

Drug Y is more fast acting than X

NEET-PG 2017

Anesthesiology