Apraclonidine differs from brimonidine in its clinical use because apraclonidine:
- A Loses effectiveness rapidly with chronic use due to tachyphylaxis and has high rates of local allergic reaction, so it is mainly used perioperatively ✓
- B Is suitable for long-term chronic glaucoma therapy but not perioperative use
- C Acts primarily as an alpha-1 agonist causing mydriasis rather than lowering IOP
- D Penetrates the blood-brain barrier and causes significant sedation
Correct answer: A. Loses effectiveness rapidly with chronic use due to tachyphylaxis and has high rates of local allergic reaction, so it is mainly used perioperatively
Explanation
Apraclonidine is a relatively selective alpha-2 agonist whose IOP-lowering effect wanes over weeks to months because of tachyphylaxis, and it causes frequent follicular conjunctivitis and contact dermatitis. Its practical niche is short-term use before and after argon laser trabeculoplasty and iridotomy to blunt procedural IOP spikes. Option C is wrong because apraclonidine is alpha-2 selective like brimonidine, and neither crosses the blood-brain barrier sufficiently to sedate.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.