Which of the following drugs is not used topically for treatment of open angle glaucoma –

Pharmacological agents used for POAG A) Topical drugs β-blockers :- Timolol, betaxolol, levobunolol, carteolol. Prostaglandin analogues :- Latanoprost, bimatoprost, travoprost. Alpha agonists :- Non-selective (epipherine, dipivefrine); selective a2 (Apraclonidine, Brimonidine). Carbonic anhydrase inhibitors :- Dorzolamide, brinzolamide. Cholinomimetic agents :- Pilocarpine, physostigmine, echothiophate, carbachol. B) Systemic drugs Carbonic anhydrase inhibitors :- Acetazolamide, dichlorphenamide, methazolamide. Hyperosmotic agents :- Mannitol, glycerol.