Question

What causes the side effects of H1 receptor antihistamines?

(a) Lack of selectivity of the H1 receptor

(b) Lack of selectivity anti-cholinergic activity

(c) Due to CNS depression

(d) Lack of selectivity of H1 receptor, anticholinergic effect, and CNS depression

I had been asked this question during an online interview.

My doubt is from Drug Concentration and Pharmacologic Response topic in division Applications of Pharmacokinetic Principles, Diuretics, Drug Concentration and Pharmacologic Response of Drug Biotechnology

Answer 1

The correct option is (d) Lack of selectivity of H1 receptor, anticholinergic effect, and CNS depression

To explain: Associated with the first generation H1-antihistamines and due to their lack of selectivity for the H1 receptor and anticholinergic activity. Side effects are due to CNS depression are sedation, dizziness, tinnitus, blurred vision, euphoria, incoordination, anxiety, insomnia, tremor, nausea/vomiting. Dry mouth/dry cough, Newer second-generation H1-antihistamines are more selective for the peripheral histamine receptors and have far fewer side effects.