Clonidine was not better than placebo for fecal incontinence despite previous reports to the contrary.
The finding, reported in the May issue of Clinical Gastroenterology and Hepatology (doi:10.1016/j.cgh.2013.06.035), gives further weight to a 2010 Cochrane review, which concluded that there was "limited evidence to guide clinicians in the selection of drug therapies for fecal incontinence," wrote Dr. Adil E. Bharucha and his colleagues. Clonidine, a centrally acting adrenergic agent, is approved to treat high blood pressure and is sometimes used to treat attention-deficit/hyperactivity disorder, dysmenorrhea, and Tourette’s syndrome.
In a placebo-controlled, double-blind study of 44 women with fecal incontinence, Dr. Bharucha of the Mayo Clinic, in Rochester, Minn., randomized 22 subjects to 0.1 mg oral clonidine twice daily or placebo.
For inclusion in the study, all subjects had to have taken the Fecal Incontinence and Continence Assessment (FICA) and reported that they were "often" or "usually" incontinent because they had "great urgency and could not reach the toilet on time."
Patients with current or prior organic colonic or anorectal diseases, including rectal cancer, were excluded, as were patients with neurologic disorders including spinal cord injury and Parkinson’s disease.
Initially, all participants underwent 4 weeks without treatment, recording their bowel habits, to establish a baseline.
That was then followed by 4 weeks of treatment with either placebo or clonidine 0.1 mg twice daily.
Patients also underwent anorectal sensorimotor function assessment at the conclusion of both the baseline period and the 4-week study period.
Dr. Bharucha found that both placebo and clonidine patients experienced an overall reduction in the number of days with at least one episode of fecal incontinence during the treatment period.
Indeed, placebo patients reported a decrease from 16 days with at least one incontinence episode during the baseline recording phase to 11 days during treatment, while clonidine patients reported a drop from 13 days during baseline to 8 days while on the drug, a difference that was not significant.
Both groups also reported a similar drop in the mean weekly FICA symptom severity score, from 9.1 to 7.6 for placebo patients and from 8.1 to 6.5 in the treatment group.
Finally, a total of eight placebo patients and seven clonidine patients reported a 50% or greater reduction in the number of days with fecal incontinence.
Looking at anorectal function, Dr. Bharucha found that the drug did not significantly affect anal resting or squeeze pressures, rectal capacity, compliance, or sensation assessed by sensory thresholds, or visual analog scale scores during rectal distention, compared with baseline measurements.
Further, "Correlations of changes during treatment in symptoms (that is, number of days and episodes of fecal incontinence, rectal urgency, and stool consistency) separately with rectal compliance and capacity and sensory thresholds were not significant," they added.
Meanwhile, looking at adverse effects, the overall incidence was significantly higher among clonidine patients, who especially reported dry mouth.
"In our prior uncontrolled study (Aliment. Pharmacol. Ther. 2010;32:681-8) with a similar dose (0.2 mg/d) of transdermal clonidine, overall effects on anorectal functions were not significant," the authors wrote.
However, that study did find that symptom relief was correlated with effects on rectal compliance and sensation in a dose-dependent manner, leading the authors to speculate that the failure of the current study might be due to inadequate dosing.
The authors stated that they had no conflicts of interest to disclose. They added that the study was supported by the National Institutes of Health.