Click here for an in-depth discussion about allergy symptoms, including a very useful “symptom analyzer” tool.
If you have only a runny nose, don’t choose a medicine that also treats headache and .
Antihistamines are classified as H1 blockers and H2 blockers, depending on the type of receptors (on the surface of cells) that they act on.
H1 receptors are associated with human tissue involving capillaries, and H2 receptors predominate in the lining of the stomach.
Antihistamines are classified into two groups – the first-generation (“sedating”) and second-generation (“non-sedating”).
Sedating antihistamines cause sedation as they are highly lipid soluble and readily cross the blood brain barrier.