Evaluation of phenylpropanolamine in the treatment of urethral sphincter mechanism incompetence in the bitch

Abstract

In a multicentre, blinded, placebo-controlled trial, 50 dogs were treated for 28 days with either phenylpropanolamine or a placebo control. Each was given at a dose of one drop per 2 kg orally three times daily, equivalent to 1 mg/kg three times daily of phenylpropanolamine. Dogs that presented with clinical signs consistent with urinary sphincter mechanism incontinence were included in the study. They were examined on three occasions by the investigating veterinary surgeon. The frequency and volume of unconscious urination were scored by veterinary surgeons according to a pre-established scoring system. Phenylpropanolamine proved to be more effective than the placebo in regard to several parameters. At day 28, 85.7 per cent of phenylpropanolamine-treated cases had no episodes of unconscious urination compared with 33.3 per cent of placebo-treated cases. This was statistically significant. Few, mild side effects were seen in either group.

Ureteral ectopia and urethral sphincter mechanism incompetence: an update on diagnosis and management options

“…In bitches this treatment is highly effective with 85∙7% dogs becoming continent after 28 days of treatment in a prospective, placebo‐controlled study (Scott et al . ) and continence rates of 90% reported in two further groups (Richter & Ling , White & Pomeroy ). Reported side effects of this medication are uncommon, but include hyperactivity, restlessness, hypertension and reflex bradycardia (Richter & Ling , Carofiglio et al .…”

Static hydraulic urethral sphincter for treatment of urethral sphincter mechanism incompetence in 11 dogs

“…In adult female dogs, the most common cause for urinary incontinence is urethral sphincter mechanism incompetence (USMI) (Holt 1985). Pharmacological management with α‐adrenergic agonists, such as phenylpropanolamine (PPA), to increase sympathetic tone in the bladder is successful in up to 85% of cases and can result in long‐term control but at least 15% of female USMI cases are refractory to treatment with conservative management (Scott and others 2002).…”

Urodynamic investigation by telemetry in Beagle dogs: validation and effects of oral administration of current urological drugs: a pilot study

“…In female dogs, the smooth urethral muscle is the preferred therapeutic target for the medical treatment of urethral sphincter mechanism incompetence (USMI) [23,24]. Despite the known contribution of smooth muscle to the maintenance of resting urethral tone, we did not observe any variation in urethral smooth muscle electrical activity during the first phase of the study.…”