Usefulness of Bisacodyl Testing on Therapeutic Outcomes in Refractory Constipation

Although chronically constipated patients usually respond to medical treatment, there is a subgroup with scarce/no response, generally labeled as refractory or intractable. However, whether this lack of response is real or due to ancillary causes (suboptimal dosage, lack of compliance etc.) is unknown.

To see whether a pharmacologic test (bisacodyl colonic intraluminal infusion during manometric assessment) may predict the therapeutic outcome.

Data of patients undergoing 24/h colonic manometry for severe intractable constipation in whom the bisacodyl test (10 ml of drug dissolved into saline and injected through the more proximal recording port) had been carried out were retrieved and analysed, and correlations with the therapeutic outcome made.

Overall, charts from 38 patients (5 men) were available; of these, only 21% displayed naive high-amplitude propagated contractions (average, less than 2/24 h), mostly meal-induced, during the recordings. A bisacodyl response was present in 31.6% patients, with a mean number of events of 1.8 per patient. After bisacodyl testing, 47.3% patients underwent intensive medical treatment, 44.7% surgery (medical failures), and 8% transanal irrigation, a procedure employed to treat refractory patients. The presence of naive propulsive contractions significantly correlated with the response to bisacodyl infusion (p < 0.0001), and with a favourable outcome to intensive medical treatment (p < 0.0001).

The bisacodyl test may be clinically useful to better categorize constipated patients erroneously labelled as intractable and to exclude true colonic inertia, thus avoiding surgery in more than 30% of these subjects.