Some types of antihistamines make one sleepy, others do not.This difference is partly attributed to a difference in
A) lipid solubility.
B) the type of receptor involved.
C) ATP-dependence of drug transport.
D) whether or not the drug mimics the hormone melatonin.

Question

Quizplus · Accepted Answer

The difference in sleepiness effect of antihistamines is partly attributed to their lipid solubility. Antihistamines that are more lipid-soluble tend to cross the blood-brain barrier more easily and can cause drowsiness by interacting with central nervous system receptors. Less lipid-soluble antihistamines do not cross the blood-brain barrier as easily and therefore do not cause drowsiness.

Some Types of Antihistamines Make One Sleepy, Others Do Not