Pineapple Predisposing Pyrexia: Pineapple Induced Serotonin Syndrome

Document Type

Conference Proceeding

Publication Date


Publication Title

American Journal of Respiratory and Critical Care Medicine


Serotonin syndrome is an often overlooked but potentially lethal diagnosis secondary to increasedserotonergic activity. It is typically associated with psychiatric meds and the toxicity can be due toan intentional overdose or polypharmacy but there are rare instances of it occurring with appropriatemedication administration. This case examines the relationship between serotonin syndrome andthe cytochrome p450 inhibition induced by pineapple juice. The patient is a 21-year-old female withpast medical history of depression and anxiety on fluoxetine and olanzapine. She presented to thehospital after being found unresponsive at home. She was hyperthermic, obtunded, and decorticateposturing with diffuse rigidity. She was intubated for airway protection with CT head, MRI head andEEG showing no acute process. Toxicology screen was negative and labs were within normal limitsother than an elevated creatinine kinase. There was concern for serotonin syndrome and she wasstarted on cyproheptadine. Patient’s parents confirmed that she was compliant with hermedications, had no history of illicit drug use and had not reported any suicidal ideation. Her pillbottles were examined and an appropriate number of pills were remaining for the month. Of note,her father reported that she had ben drinking almost 2 liters of pineapple juice every day for the lastseveral weeks. 48 hours after admission, cessation of all psychiatric meds and administration ofcyproheptadine, patient was extubated and mentating well. This patient illustrates a case ofserotonin syndrome with appropriate use of serotonergic drugs but toxicity induced by the CYP450inhibition caused by pineapple juice. The CYP group of dealkylating enzymes are responsible forapproximately 75% of metabolic reactions in the body. Pineapple contains bromelain, a cysteineprotease. This enzyme inhibits CYP2C9 activity while the cysteine protease inhibitor, E-64, is alsoblocked by bromelain. This mechanism details the process by which pineapple juice is able toinhibit the cytochrome pathway which is essential for the metabolism of serotonin. In patients takingselective serotonin reuptake inhibitors and presenting with altered mental status, hemodynamicinstability and neuromuscular abnormalities, serotonin syndrome must be considered. Furthermore,attention should be paid to the patient’s dietary choices as fruits such as pineapple can inhibit thecytochrome pathway which will lead to the inability of the body to metabolize serotonergic drugs andresult in potentially lethal complications.





First Page



American Thoracic Society International Conference, May 13-18, 2022, San Francisco, CA.