Adverse drug events related to COX inhibitors in patients presenting at an emergency department

The use of cyclooxygenase (COX) inhibitors is increasingly common. Most of them are available for self-medication, either as analgesic or for cardio- and cerebrovascular prevention.

We aimed to analyze adverse drug events (ADE) related to COX inhibitors and the concomitant use of proton pump inhibitors (PPI) according to guidelines in patients presenting at an emergency department (ED).

In a prospective study, 2262 patients presenting consecutively at the ED of a tertiary care university teaching hospital were evaluated by intensive chart review in order to detect and classify all ADE. In this cross-sectional analysis all patients taking COX inhibitors at home were evaluated further.

Of all evaluated patients, 753 (33.3 %) took COX inhibitors at home, 258 (34.3 %) with concomitant PPI. A total of 168 (22.3 %) patients suffered from at least one ADE related to COX inhibitors. The most common ADE observed were anemia (55.9 %) and gastrointestinal ADE (31.6 %, e. g., bleeding, gastritis, and ulcer). In 10.1 % of patients, a medication error (e. g., intake without proper clinical indication) contributed to the ADE and in 40.8 % of the ADE involved further contributing drugs. Only 38.8–42.1 % of patients with a high gastrointestinal risk were prescribed a PPI concomitantly.

ADE related to COX inhibitors were found in every fifth patient taking COX inhibitors. One-tenth of all ADE involving COX inhibitors were related to medication errors. The guideline-based concomitant use of PPI was only in part implemented.