Lidocaine inhibits leukocyte migration and phagocytosis in monosodium urate crystal-induced synovitis in dogs.

Local anesthetics can inhibit several leukocyte functions and have been shown to have an antiinflammatory effect in studies on experimental peritonitis. In this investigation intravenous lidocaine was given to dogs prior to or after injection of monosodium urate crystals into their knee joints. Lidocaine was used in high doses or lower doses comparable to those used clinically for cardiac arrhythmias. Lidocaine started before crystal injection and given at either dose schedule decreased the expected rise in synovial fluid leukocyte counts and the percentage of cells with phagocytized crystals. This effect was transient and reproducible. Lidocaine was not effective in one dog when started 1 h after the crystal injection.