title: Chronic use of apraclonidine decreases its moderation of post-laser intraocular pressure spikes.
abstract: OBJECTIVE
  The purpose of the study is to investigate the efficacy of 1.0% apraclonidine in preventing intraocular pressure (IOP) spike after argon laser trabeculoplasty (ALT) in patients on chronic apraclonidine therapy compared with patients not on chronic apraclonidine use.
  
  
  METHODS
  The study design was a prospective study.
  
  
  METHODS
  This study consisted of 231 consecutive eyes of patients with primary open-angle glaucoma undergoing ALT: 70 eyes (30%) were started on a regimen including chronic apraclonidine 0.5% use (group A) and 161 eyes (70%) were started on a regimen without chronic apraclonidine 0.5% use (group B).
  
  
  METHODS
  Both groups received one drop of apraclonidine 1.0% 15 minutes before ALT to 180 degrees of previously untreated trabecular meshwork. Intraocular pressure was measured before the procedure and at 5 minutes, 1 hour, and 24 hours after the laser treatment.
  
  
  METHODS
  Incidences of an IOP spike and mean IOPs at 5 minutes, 1 hour, and 24 hours after the laser treatment were compared between the two groups. Multivariate logistic regression analysis also was carried out to identify the significant risk factors for post-ALT IOP spikes despite prophylactic apraclonidine 1.0% treatment.
  
  
  RESULTS
  The incidences of IOP spikes greater than 0 mmHg, greater than 2 mmHg, and greater than 5 mmHg at 1 hour after ALT were 32.9%, 22.9%, and 12.9%, respectively, in group A versus 13.7%, 11%, and 3.1%, respectively, in group B (P = 0.0007, P = 0.009, and P = 0.004). Chronic apraclonidine 0.5% use was found to be the only significant risk factor for IOP spikes at 1 hour after ALT by multivariate logistic regression analysis.
  
  
  CONCLUSIONS
  The incidences of IOP spikes in group A were significantly greater than in group B and approached the reported incidences of IOP spikes without perilaser apraclonidine prophylaxis. This indicates that peri-ALT apraclonidine is relatively ineffective in patients with chronic apraclonidine 0.5% use (group A) compared with patients without chronic apraclonidine use (group B), presumably because of saturation of the ocular alpha-2 receptors with apraclonidine in patients with chronic apraclonidine use. Therefore, in patients receiving chronic apraclonidine therapy, it is especially important to monitor their post-ALT IOPs and to be prepared to treat postlaser IOP spikes using agents other than apraclonidine.
authors.affiliation: Kresge Eye Institute, Wayne State University, Detroit, Michigan 48201-1423, USA.
authors.forename: H S
authors.initials: HS
authors.lastname: Chung
authors.forename: D H
authors.initials: DH
authors.lastname: Shin
authors.forename: C M
authors.initials: CM
authors.lastname: Birt
authors.forename: C
authors.initials: C
authors.lastname: Kim
authors.forename: D
authors.initials: D
authors.lastname: Lee
authors.forename: D S
authors.initials: DS
authors.lastname: Levin
authors.forename: R
authors.initials: R
authors.lastname: Hakimzadeh
authors.forename: M S
authors.initials: MS
authors.lastname: Juzych
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000368:Aged; D003000:Clonidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D005902:Glaucoma, Open-Angle / Q000188:drug therapy / Q000601:surgery*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D053685:Laser Therapy / Q000009:adverse effects*; D008297:Male; D009883:Ophthalmic Solutions; D011183:Postoperative Complications / Q000517:prevention & control*; D011446:Prospective Studies; D014130:Trabeculectomy
chemical_list: D000316:Adrenergic alpha-Agonists; D009883:Ophthalmic Solutions; C016986:apraclonidine; D003000:Clonidine