Fentanyl-clarithromycin interaction.

This case describes an incident where a patient with breast cancer and bone metastases, who was using a fentanyl patch, was started on a course of clarithromycin and experienced a respiratory arrest 2 days later. She was a hospital inpatient at the time and was treated with naloxone and the fentanyl patch was stopped at the time of the reaction. She recovered but was left without pain relief until seen in clinic by the palliative care consultant who restarted the fentanyl patch without further problems.