Dose range finding study for the efficacy of meloxicam administered prior to sodium urate-induced synovitis in cats

Abstract

ObjectiveTo determine the lowest efficacious dose of oral meloxicam for relieving pain in cats with a sodium urate (SU)-induced acute inflammatory synovitis. Study designRandomized, blinded, controlled, and four-way crossover study. AnimalsEight surgically neutered cats (four males, four females) paired according to sex. MethodsEach pair of cats was treated with 0 (placebo), 0.025, 0.05, or 0.075 mg kg−1 oral meloxicam once daily for 4 days prior to injection, into alternating stifles, of 1 mL of 20 mg mL−1 SU crystals, beginning with the right stifle. Each cat received each of the four treatments, separated by at least 21 days. Analgesic efficacy was evaluated based on objective (e.g., pressure mat data total force, contact pressure, and contact area) and subjective (e.g., scores for Analgesia Scale [AS], Lameness Scale [LS], and Visual Analog Scale [VAS]) outcome measures for pain assessment. All outcome measures were recorded before and during 30 hours after SU injection. The pre-defined primary outcome measure was the area under the response–time curve (AUC0–30 hours) of the total force of the injected limb. Data were analyzed by analysis of variance. A sequential test procedure was applied and the test sequence stopped in case of a nonsignificant result. ResultsMeloxicam at doses of 0.05 and 0.075 mg kg−1 day−1 PO was significantly different from placebo for the pre-defined primary outcome measure (i.e., AUC0–30 hours of total force). All tested meloxicam doses were lower than placebo for the subjective outcome measures (i.e., AUC0–30 hours of AS, LS, and VAS). Conclusions and clinical relevanceThe lowest efficacious dose of meloxicam for relieving pain in cats with an SU-induced synovitis was 0.05 mg kg−1 day−1 PO according to the pre-defined primary outcome measure. However, lower doses may also be effective as seen in the subjective outcome measures.