H1 antihistaminics afford benefit in a number of conditions

NEET SS
#1

H1 antihistaminics afford benefit in a number of conditions. All of the following conditions are benefited by antagonism of histamine EXCEPT :

  1. Dermographism

  2. Insect bite

  3. Common cold

  4. Seasonal hay fever

Explanation:

In this condition, excessive secretions (like rhinorrhoea) are due to cholinergic overactivity. First generation antihistamin-ics possess anticholinergic property and therefore are effective for common cold. On the other hand, second generation agents (lacking anticholinergic actions) are ineffective.