Case Presentation: 28-year-old female with past medical history of bipolar disorder, schizoaffective disorder, cannabis use disorder who presented to ED with altered mental status and bizarre behaviors along with multiple vomiting episodes at home. On physical examination patient was found to be in confused state with difficulty in following commands, internally distracted though no gross focal findings. ED labs significant for leukocytosis, urine drug screen positive for THC, UA positive for ketones, Serum sodium, potassium and chloride were mildly low, but had markedly elevated Anion gap of 26 with a normal osmolar gap. Both Beta-hydroxybutyrate (3.3) and lactic acidosis (2.3) were mildly increased. Arterial blood gas showed a triple acid base disturbance. CT head negative for any acute pathology but found to have QT prolongation on EKG. Additional collateral history from boyfriend significant for concerns of possible seroquel, ambien ingestion and an empty gallon of pure grapefruit juice was found at bedside. Infectious work up obtained, patient started on intravenous fluids and admitted to Med-Psych unit. Mental status and laboratory abnormalities quickly improved. Patient denied intentional overdose or suicidal ideation and drank 1 gallon of grapefruit/detox juice a day prior to presentation. Etiology of her illness though possibly multifactorial was felt mainly driven by seroquel toxicity in setting of grapefruit juice. She was restarted on seroquel at lower dose, educated on drug interactions and discharged home in stable condition.
Discussion: Grapefruit juice is being used in various detoxification diets but is a potent cytochrome P450 enzyme inhibitor causing multiple drug interactions. Quetiapine undergoes significant first pass metabolism by CYP34A, inhibition of which can lead to elevated quetiapine levels and unintentional overdose. This can be extremely dangerous with co-ingestions or patients with multiple medications causing additional drug-drug interactions leading to cardiac arrhythmias, rhabdomyolysis and CNS depression.
Conclusions: Hospitalists should be aware of various dietary cytochrome P450 enzyme inhibitors and educate patients about potential interactions which can result in unintentional overdose and patient harm.