Possible ischaemic colitis after bisacodyl use

The Netherlands Pharmacovigilance Centre Lareb received two reports of ischaemic colitis after bisacodyl use. Ischaemic colitis often resolves spontaneously, but colonic surgery is sometimes required. Attention for this potential adverse drug reaction is warranted.

Bisacodyl is a laxative that is used for constipation and bowel preparation for diagnostic test or surgery. The Netherlands Pharmacovigilance Centre Lareb received two reports in which ischaemic colitis appeared within hours after bisacodyl intake. If used for bowel preparation, bisacodyl is often combined with other drugs such as macrogol/electrolytes. The Dutch Summary of Product Characteristics (SmPC) of macrogol/electrolytes includes a warning for ischemic colitis if it is being used for bowel preparation.

Lareb reports
The Netherlands Pharmacovigilance Centre Lareb received two reports in which ischaemic colitis appeared within hours after bisacodyl intake. In both reports the indication of bisacodyl was bowel preparation for diagnostic tests. In one report macrogol/electrolytes was reported as concomitant drug. In both cases the patients recovered within days without treatment.

Ischaemic colitis
Ischaemic colitis occurs when the blood flow in the colon is impaired. Patients with ischaemic colitis often present with acute severe abdominal pain and anal haemorrhage. In some patients this can lead to tissue death due to a lack of oxygen, which might require surgery. However, ischaemic colitis recovers spontaneously in most patients. Bisacodyl can cause ischaemic colitis by increasing the pressure in the colon, which may hinder and even disrupt blood flow in the colon. Another hypothesis is that ischaemia can occur when the elevated oxygen demand due to the increased colonic motility cannot be met.

Risk factors
There are several known risk factors of ischaemic colitis, including cardiovascular diseases, abdominal surgery and several drugs. It is possible that patients with these risk factors are more susceptible to the effects of bisacodyl, increasing the risk of ischaemic colitis in these patients.

Action
‘Colitis’ is listed as a side effect of bisacodyl in the patient information leaflet (PIL) and SmPC. However, it is not specified that ischaemic colitis can also occur and that this can appear within hours after administration. The Netherlands Pharmacovigilance Centre Lareb has informed the Dutch Medicines Evaluation Board (MEB) about the reports. The MEB asks the marketing authorisation holder to further investigate this and the adjust the PIL and SmPC if necessary. In addition, the marketing authorisation holder is asked to add a warning in the PIL and SmPC comparable to the warning in the PIL and SmPC of macrogol/electrolytes.

The full overview of the reports can be found here.