This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following medications is contraindicated in patients with allergy to sulphonamides? 
Select and explain. 
A. Levobunolol, B. Bimatoprost, C. Brinzolamide, D. Brimonidine
C: Brinzolamide
Answer: C: Brinzolamide 
Explanation: Acetazolamide, Dorzolamide and Brinzolamide are sulfonamide derivatives which act by inhibiting carbonic anhydrase (carbonic anhydrase inhibitor). Being sulphonamide derivatives they are contraindicated in patients with allergy to sulphonamides. Ref: Essentials of Pharmacology By K D Tripathi, 5th Edition, Pages 188, 553; Medicinal Chemistry By Sriram, Page 227.