Initial treatment factors associated with feline urethral obstruction recurrence rate: 192 cases (2004–2010)

Abstract

At 24 hours and 30 days after IUC, rUO rates in prazosin-treated cats were significantly lower than rates in phenoxybenzamine-treated cats. Reobstruction rate at 24 hours was significantly lower when a 3.5F versus 5F urinary catheter was used.

The effect of prazosin on outcome in feline urethral obstruction

“…Therefore, there is a possibility that the prazosin dose and frequency of administration used in this study was too low to have had an effect on rUO. In a previous retrospective study, cats receiving prazosin had a decreased rUO compared with cats receiving phenoxybenzamine. The dosage of prazosin administered in that report was much higher (0.5–1.0 mg/cat q 12 h) than that of the current study, which may explain the differing study results.…”

“…The dosage of prazosin administered in that report was much higher (0.5–1.0 mg/cat q 12 h) than that of the current study, which may explain the differing study results. In this same report, no hypotension was seen in the cats in which SBP was monitored . However, more evidence is needed on the safety of these higher doses and the usefulness of prazosin in the treatment of rUO before its use is widely accepted in clinical practice.…”

“…There is no information in the veterinary literature evaluating the effect of the presence of admission urinary tract infection or catheter‐associated urinary tract infection on rUO, which is another limitation of our study because these cats were not excluded from analysis. However, the administration of antimicrobials has not been associated with rUO in two previous reports …”

“…Urethral spasm is hypothesized to play a role in rUO, and a 1‐month treatment period was chosen because urethral spasm may be incited by urinary catheterization, ongoing or recurrent idiopathic cystitis, or a combination of these etiologies Although this study failed to find a difference in the rate of rUO among cats receiving prazosin and those receiving placebo, these results should be evaluated cautiously as our study was underpowered to detect this difference. In two recent studies on feline UO (both of which were published after our clinical trial was already completed), the overall rUO rate ranged from 14 to 24%, whereas we powered our study based on a 50% rUO rate. During our 1‐month study medication period, our rUO rate was 15% in the prazosin group and 17% in the placebo group.…”

“…Recently, several reports have evaluated risk factors for rUO in cats. In one retrospective study, the administration of prazosin rather than phenoxybenzamine was associated with a reduced rUO rate. However, because of the retrospective design of that study, it is difficult to determine whether prazosin administration alone was responsible for the reported reduction in rUO, as other factors such as diet and environmental management following UO were not controlled.…”