Lipid Emulsion Therapy in Diphenhydramine Overdose

Introduction: Diphenhydramine is a common over-the-counter antihistamine, which in toxic quantities can have serious adverse effects such as arrhythmias, seizures and death. Toxicity is thought to be mediated via sodium-channel blockade, conventional treatment is intravenous sodium bicarbonate infusions. A few recent case reports suggest the addition of lipid emulsion therapy may be effective in diphenhydramine overdoses. Case presentation: A 30-year-old Hispanic female with previous history of depression and prior suicide attempts ingested 5 grams (200 tablets) of diphenhydramine 30 minutes prior to arrival. She presented obtunded with hemodynamic instability and seizures. EKG showed a wide-complex tachycardia with a rate of 180. In efforts to improve her hemodynamic instability, ampules of sodium bicarbonate were administered in 2 minute intervals. Unfortunately after giving 7 ampules total, there was only minimal improvement in the patients wide-complex tachycardia. Deviation of management: After minimal improvement with conventional therapy, intravenous lipid emulsion bolus and drip was given. Approximately one minute after the bolus was administered, the patients wide-complex tachycardia converted to normal sinus rhythm and her vital signs stabilized. Discussion comments: The patient was intubated for airway protection, gastric lavage removed large amounts of pink sediment, and lorazepam was given for her seizures. The patient was stabilized and later discharged from the hospital Conclusion: Lipid emulsion therapy is utilized in numerous medication overdoses, however there are limited studies on its efficacy with diphenhydramine overdose. Hopefully this case exemplifies its efficacy and leads to further investigative research. Grants: None