Lower urinary tract obstruction is a common problem in cats worldwide, account for over 10% of veterinary visits. This syndrome is characterized by obstruction of the feline urethra leading to an inability to urinate causing distension of the bladder, pain, and eventually renal failure and potentially death. It occurs almost exclusively in male cats due to their longer, narrower urethra. There are many potential predisposing causes to urinary obstruction, including infections, stones or crystals, inflammatory disease, or cancers. While the survival rate of obstructive lower urinary disease is excellent, recurrence is a major concern. Management of pain, inflammation, and inappropriate urination in the post-obstructive period are also critical in the post-obstructive period.
A major cause of urinary obstruction in cats is Feline Idiopathic Cystitis (FIC). This condition is characterized by inflammation of the bladder wall without an obvious inciting cause. While definitive diagnosis of FIC entails bladder scoping, symptomatic diagnosis is usually obtained by ruling out other causes. FIC is linked to dietary factors and genetics, but most importantly to stress and a lack of environmental stimulation.
Therapy for urethral obstruction is multifactorial and involves resolving symptoms while attempting to remove inciting causes. After catheterization and emergency stabilization are complete, therapy usually consists of a “urinary diet”, pain management, and urethral relaxants. Many additional medical therapies have been suggested, including anti-inflammatories (both steroids and non-steroidal), benzodiazepines, polyunsaturated fatty acids and glycosaminoglycan’s, and others. While none of these have been proven conclusively beneficial, they are often employed alone or in combination by veterinarians.
This study attempted to determine if therapy with a common veterinary NSAID (meloxicam) was effective in reducing the risk of re-obstruction after catheter removal. Cats included in the study suffered from FIC; those with urolithiasis, infection or neoplasia were excluded. The study was designed as a prospective, double blinded, placebo controlled randomized trial. 37 cats with obstructive FIC were evaluated, 18 of which were included in the meloxicam group and 19 in the placebo. Each group contained approximately the same number of DSH and purebred cats, with a similar age. All cats were neutered males.
Cats were catheterized and stabilized after admission, and administered a 0.1mg/kg dose of meloxicam orally on day one, followed by 0.05mg/kg every 24 hours for the next four days. Recurrence of urethral obstruction was defined as a cat attempting to urinate unsuccessfully despite an enlarged urinary bladder. Questionnaires, telephone surveys, and recheck physical exams were used to monitor treatment success. Cats were monitored for appetite, bladder pain, urine and blood parameters.
During the course of the study there was no significant difference found in risk of re-obstruction between treatment groups. No change was found in blood or urine parameters or owner questionnaires. There was a slight improvement in abdominal pain prior to the first recheck in the meloxicam treated group, but no other difference in pain scores. Recurrence rate in the first 7 days was 22.2% in the meloxicam treated group and 26.3% in the placebo group. In the first three months, recurrence was 33.3% in the meloxicam group and 31.5% in the placebo group.
While the doses used in this study were consistent with common guidelines, it is possible that higher doses may have been more effective while remaining within the margin of safety. The cats in the meloxicam group, on average, were affected with more chronic and severe IC, which may also have biased the study.
While the use of NSAID therapy in urethral obstruction has a strong theoretical basis, this study failed to show any effectiveness in reducing the risk of recurrence or accelerating recovery. Potential for analgesic and anti-inflammatory benefits in combination with other drugs was not definitively ruled out. While further research into this area is needed, this paper indicates that in patients with renal, hepatic, or other compromise, the risks of NSAID use likely outweigh potential benefits. (MRK)