At work the next week, Joe realizes he forgot to take his Zyrtec that morning and he has a big presentation. His colleague gives him a Claritin. Amazingly, Joe finds it works just fine. Which explanations in b fits ALL THREE pieces of data: 1) Joe became tolerant to Claritin,
2) Zyrtech worked when he was tolerant to Claritin and
3) When Joe switched back to Claritin from Zyrtech, Claritin worked again.
A. Cetirizine has higher affinity than loratadine
B. Cetirizine has lower affinity than loratadine
C. Cetirizine is an inverse agonist and loratadine is a neutral antagonist and the receptor is constitutively active
D. Cetirizine is an inverse agonist and loratadine is a neutral antagonist and the receptor has no constitutively activity
E. Loratidine promoted upregulation of H1 receptors, and Cetirazine drives downregulation of H1 receptors
F. Loratidine promoted downregulation of H1 receptors, and Cetiriazine promotes upregulation of H1 receptors