Double-blind parallel comparison of multiple doses of apraclonidine, clonidine, and placebo administered intra-articularly to patients undergoing arthroscopic knee surgery

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. DISCUSSION: 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.