Evaluation of a Pharmacist-Driven Protocol for the Treatment of Opioid-Induced Constipation

Opioid-induced constipation (OIC) treatment guidelines recommend over-the-counter laxatives as first-line therapy, followed by treatment with a peripherally-acting mu-opioid receptor antagonist (PAMORA) in refractory patients.

To evaluate the ability of a pharmacist-driven OIC protocol to promote increased scheduled laxative use prior to escalation to PAMORA therapy.

This retrospective, single-center cohort study evaluated patients 2 years pre- and post-protocol implementation. The primary outcome was the difference in the percentage of patients receiving 2 scheduled laxatives for ≥ 2 days prior to PAMORA therapy pre- and post-protocol. Secondary outcomes included difference in time to first bowel movement after PAMORA initiation, difference in total number of laxative/PAMORA doses administered, and difference in overall estimated total cost. Data was analyzed using chi-squared tests and Student's t tests.

Three-hundred patients were included (150 patients in the pre and post-protocol groups). In the pre-protocol group, 53 patients (35%) received 2 scheduled laxatives for 2 days prior to naloxegol/methylnaltrexone compared to 96 patients (64%) in the postprotocol group (p < 0.0001). One-thousand twenty-one scheduled laxative doses were given pre-protocol versus 1625 doses post-protocol. Average time to first bowel movement was similar between groups (17.7 hours vs 16.0 hours p = 0.441). Estimated total cost of OIC reversal therapy decreased from $20,896.95 to $13,405.47.

A pharmacist-driven OIC protocol is associated with an increase in the use of scheduled laxatives prior to PAMORA administration and decreased overall estimated total cost. A larger, prospective study is necessary to assess if this promotes more efficacious OIC.