This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
Dorzolamide is a 
Select and explain. 
A. Second generation sulfonylurea hypoglycaemic, B. Topical sulfonamide antibacterial, C. Luminal amoebicide, D. Topically applied ocular carbonic anhydrase inhibitor
D: Topically applied ocular carbonic anhydrase inhibitor
Answer: D: Topically applied ocular carbonic anhydrase inhibitor 
Explanation: Carbonic anhydrase inhibitors Include Acetazolamide,Dorzolamide. Dorzolamide (2% eyedrops BD-TDS):- It is a topically useful carbonic anhydrase inhibitor. It lowers i.o.t. by ~20%; somewhat less efficacious than timolol. side effects:- Ocular stinging, burning, itching, corneal edema and bitter taste. Dorzolamide is used only as add on drug to topical b blockers/PG analogues, or when these drugs are contraindicated. Ref:- kd tripathi; pg num:-155