From the FDA Drug Label
In case of accidental overdose, get medical help or contact a Poison Control Center right away (1-800-222-1222) The treatment for Benadryl (diphenhydramine) toxicity is to get medical help or contact a Poison Control Center right away, such as by calling 1-800-222-1222 1.
From the Research
Treatment for Benadryl (diphenhydramine) toxicity primarily involves supportive care while the medication is metabolized and eliminated from the body. For mild to moderate toxicity, treatment includes monitoring vital signs, providing intravenous fluids to maintain hydration. However, according to the most recent and highest quality study available 2, patients with acute ingestions of less than a toxic dose of diphenhydramine, or chronic exposures to diphenhydramine and no or mild symptoms, can be observed at home with instructions to call the poison center back if symptoms develop or worsen. Some key points to consider in the management of diphenhydramine toxicity include:
- Referral to an emergency department is recommended for patients with suicidal intent, intentional abuse, or suspected malicious intent, as well as those experiencing moderate to severe symptoms such as agitation, hallucinations, or respiratory depression 2.
- For patients referred to the emergency department, transportation via ambulance should be considered based on the patient's condition and the expected time to arrival 2.
- Intravenous sodium bicarbonate may be administered by EMS personnel if QRS widening is present and authorized by medical direction 2.
- Benzodiazepines may be administered by EMS personnel if agitation or seizures are present and authorized by medical direction 2. It's also important to note that diphenhydramine toxicity can cause anticholinergic effects, including dry mouth, blurred vision, urinary retention, tachycardia, hyperthermia, confusion, and hallucinations, which typically resolve as the drug is eliminated with a half-life of approximately 2-8 hours. Cardiac monitoring is essential as diphenhydramine can cause QT prolongation and arrhythmias, as highlighted in a case report where a patient presented with a wide complex tachycardia due to sodium channel blockade 3. In rare cases, diphenhydramine overdose can manifest with electrocardiographic signature of the Brugada syndrome, as reported in a case study 4. Overall, the management of diphenhydramine toxicity requires a supportive care approach, with consideration of the patient's symptoms, medical history, and potential complications.