title: Double-blind parallel comparison of multiple doses of apraclonidine, clonidine, and placebo administered intra-articularly to patients undergoing arthroscopic knee surgery.
abstract: OBJECTIVE
  This clinical study assessed and compared the potential analgesic and adverse effect of IA apraclonidine with IA clonidine.
  
  
  METHODS
  Eighty patients scheduled for arthroscopic knee surgery under general anesthesia were randomized to receive, in a double-blind manner, either IA normal saline (group 1), 50 microg IA apraclonidine (group 2), 150 microg IA apraclonidine (group 3), or 150 microg IA clonidine (group 4), all in a volume of 20 mL subsequent to surgery. Visual analog pain scores (VAS), the duration of analgesia as defined by the time to first demand for supplemental analgesics, the subsequent 24-hour consumption of postoperative supplementary analgesics, and patient adverse effects were evaluated.
  
  
  RESULTS
  The patients from groups 3 and 4 demonstrated a longer duration of analgesia and used fewer analgesics in the first postoperative 24 hour period compared with group 1 and 2 patients (P < 0.05). The VAS scores corresponding to the periods 1, 2, and 4 hours postoperatively were significantly lower for group 3 than for group 1 patients. The VAS scores at 1 and 4 hours postoperatively were also lower for group 3 than for group 2 patients (P < 0.05). There was no significant difference in the incidence of side effects among the 4 groups.
  
  
  CONCLUSIONS
  The IA application of 150 microg apraclonidine and 150 microg clonidine provide similar degree of postoperative analgesia following knee arthroscopic surgery without any difference in adverse events.
authors.affiliation: Department of Biological Science, National Sun Yat-Sen University, andDepartment of Anesthesiology, E-DA Hospital, I-Shou University, Kaohsiung, Taiwan, Republic of China. tanph@gcn.net.tw
authors.forename: Ping-Heng
authors.initials: PH
authors.lastname: Tan
authors.forename: Hartmut
authors.initials: H
authors.lastname: Buerkle
authors.forename: Jiin-Tsuey
authors.initials: JT
authors.lastname: Cheng
authors.forename: Hsun-Chang
authors.initials: HC
authors.lastname: Shih
authors.forename: Wen-Ying
authors.initials: WY
authors.lastname: Chou
authors.forename: Lin-Cheng
authors.initials: LC
authors.lastname: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000700:Analgesics / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D001168:Arthritis / Q000601:surgery; D001182:Arthroscopy / Q000009:adverse effects / Q000379:methods; D003000:Clonidine / Q000008:administration & dosage* / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007270:Injections, Intra-Articular / Q000379:methods; D007717:Knee / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000187:drug effects; D010149:Postoperative Pain / Q000188:drug therapy* / Q000209:etiology; D010919:Placebos / Q000008:administration & dosage / Q000627:therapeutic use; D013997:Time Factors
chemical_list: D000700:Analgesics; D010919:Placebos; C016986:apraclonidine; D003000:Clonidine