A histamine antagonist (commonly called an antihistamine) is a pharmaceutical drug that inhibits the action of histamine by either blocking its attachment to histamine receptors, or inhibiting the enzymatic activity of histidine decarboxylase which catalyzes the transformation of histidine into histamine (atypical antihistaminics). Histamine antagonists are commonly used for the relief of allergies caused by intolerance of proteins.



![70x Hayfexo 180mg + 30x [Short Dated] Cetirizine 10mg - $13.99 Delivered @ PharmacySavings](https://files.ozbargain.com.au/n/82/825482.jpg?h=5f911d83)
![[Short Dated] Cetirizine 10mg Hayfever Relief Various Brands from $2.49 Per 10 (Long Dated Available) Delivered @PharmacySavings](https://files.ozbargain.com.au/n/13/823513.jpg?h=1e27fa1c)














