MAO inhibitors and coronary artery surgery: a patient death

Abstract

The mechanisms of action of monoamine oxidase inhibitors (MAOIs) suggest that patients taking them may respond with hyper- or hypotension when undergoing coronary artery surgery. We describe a case where MAOIs were present and fentanyl and midazolam were the anaesthetic agents used. The anaesthesia and surgery were performed without incident. Postoperative ICU care was complicated by hypertension, hyperthermia, and severe shivering followed by hypotension resistant to therapy and finally death. Diagnoses of pulmonary embolism and sepsis were unproven and may have played a role. The MAOIs may also have played a role. Reactions in patients while taking both meperidine and MAOIs are unusual and animals react differently from humans to a combination of MAOIs and narcotics. There are only five reported cases where fentanyl was given to patients on MAOIs. We conclude that, until there is more information, MAOIs should be discontinued, if possible, before surgery in which catecholamines may be needed.