Anesth Analg 1999;89:802
© 1999 International Anesthesia Research Society
LETTERS TO THE EDITOR
Intraarticular "Analgesics": Are They Safe?
Hartmut Buerkle, MD
Klinik und Poliklinik für Anästhesiologie und operative Intensivmedizin Westfälische Wilhelms-Universität Münster 48129 Münster, Germany
I read with great interest the article by Reuben and Connelly (1) describing a significant improvement in postoperative analgesia after the intraarticular (IA) injection of clonidine along with bupivacaine in patients undergoing ambulatory meniscetomy. Their findings for IA clonidine are in accordance with observations by Gentili et al. (2,3). However, both studies would have been more powerful by an improved study design, i.e., prestudy power analysis and determination of the sample size, which should be always performed, especially when dealing with small group sizes. Thus, because of the limited study designs, Reuben and Connelly may have exaggerated the rate of side effects after the administration of IA clonidine by reporting that 20% of the patients experienced either hypotension or bradycardia in the study by Gentili et al. (2) (one patient each experienced either a brief episode of arterial hypotension [<90 mm Hg] or bradycardia [heart rate <45 bpm]; no baseline values were provided). In addition, there is more crucial informations missing in their study description: 1) whether a tourniquet was used (for how long, etc.) and 2) whether IA drainage was used. In my clinical experience, both interventions affect the incidence of side effects seen after IA clonidine (no side effects observed over 8 h postoperatively with 75 µg or 150 µg of IA clonidine, tourniquet inflated until 15 min after IA injection, drainage opened 30 min after last suture).
Recently, new interest has focused on peripherally mediated analgesia by opioids, cholinergics, or acetylcholinesterase inhibitors, nonsteroidal antiinflammatory drugs, and other centrally active analgesics, such as the  2-agonist clonidine (4–6). The IA injection of antinociceptive agents presents a widely used model for the identification of peripherally mediated analgesia. However, there are no proper preclinical or clinical assessments of local tissue toxicity provided, nor are there any data published on the physicochemical characteristics of the drug combinations being injected IA (6). Not surprisingly, a recent study in rats showed that a single IA injection of ketorolac resulted in knee joint inflammation (7).
Despite all the precautions being used (e.g., sterile techniques) and despite our shared scientific/clinical enthusiasm for improvement of postoperative analgesia, studies about "new" routes of administration for "old" drugs should incorporate additional data on the safety of their use.
References
-
Reuben SS, Connelly NR. Postoperative analgesia for outpatient arthroscopic knee surgery with intraarticular clonidine. Anesth Analg 1999;88:729–33.[Abstract/Free Full Text]
-
Gentili M, Juhel A, Bonnet F. Peripheral analgesic effect of intra-articular clonidine. Pain 1996;64:593–6.[Web of Science][Medline]
-
Gentili M, Houssel P, Osman M, et al. Intra-articular morphine and clonidine produce comparable analgesia but the combination is not more effective. Br J Anaesth 1997;79:660–1.[Abstract/Free Full Text]
-
Buerkle H, Yang LC, Marcus MA, et al. Opioidergic and cholinergic peripheral pain mechanisms. Acta Anaesthesiol Scand Suppl 1997;111:184–6.[Medline]
-
Yang LC, Chen LM, Wang CJ, Buerkle H. Postoperative analgesia by intra-articular neostigmine in patients undergoing knee arthroscopy. Anesthesiology 1998;88:334–9.[Web of Science][Medline]
-
Reuben SS, Connelly NR. Postoperative analgesia for outpatient arthroscopic knee surgery with intraarticular bupivacaine and ketorolac. Anesth Analg 1995;80:1154–7.[Abstract]
-
Irwin MG, Cheung KM, Nicholls JM, Thompson N. Intra-articular injection of ketorolac in the rat knee joint: effect on articular cartilage and synovium. Anaesth 1998;80:837–9.
This article has been cited by other articles:
|
