From the Guidelines
A Benadryl overdose can lead to serious long-term effects, including permanent cognitive impairment, memory problems, and dementia-like symptoms, due to anticholinergic toxicity, as reported in studies on the effects of first-generation antihistamines 1. When considering the long-term effects of a Benadryl overdose, it is essential to prioritize the potential for morbidity, mortality, and impact on quality of life. The evidence suggests that first-generation antihistamines, such as diphenhydramine, can cause significant sedation, performance impairment, and anticholinergic effects, which can be particularly problematic in older adults and individuals with concomitant comorbid conditions 1. Some of the potential long-term effects of a Benadryl overdose include:
- Permanent cognitive impairment and memory problems
- Dementia-like symptoms
- Heart rhythm abnormalities and cardiovascular damage
- Liver damage due to the metabolism of diphenhydramine by the liver
- Psychological effects, such as anxiety, depression, and psychosis
- Rhabdomyolysis, which can cause permanent kidney damage It is crucial to seek immediate medical attention if a Benadryl overdose is suspected, as treatment within hours of ingestion can significantly improve outcomes and reduce the risk of permanent damage. The anticholinergic properties of diphenhydramine, which block acetylcholine in the brain, explain many of these long-term effects when taken in excessive amounts 1.
From the Research
Long Term Effects of Benadryl Overdose
- The long term effects of Benadryl overdose can be severe and potentially life-threatening 2, 3, 4, 5, 6
- Studies have reported cases of cardiac arrest, status epilepticus, coma, and cardiac arrhythmias following Benadryl overdose 2, 3, 5, 6
- In some cases, patients have survived with aggressive treatment, including physostigmine, sodium bicarbonate, and extracorporeal membrane oxygenation (ECMO) 2, 4, 6
- However, high intake of Benadryl is associated with death, and caution should be exercised in cases of drug overdose 3
Treatment and Management
- Conventional treatment for Benadryl overdose includes sodium bicarbonate infusion and supportive care 5
- Lipid emulsion therapy has been used in some cases to stabilize and manage patients with severe Benadryl overdose 4
- ECMO has been used in cases of refractory ventricular fibrillation and cardiac arrest following Benadryl overdose 6
- Aggressive control of seizures, sodium bicarbonate therapy, and recognition of physostigmine contraindication are important aspects of management 5
Prognosis and Outcome
- The prognosis and outcome of Benadryl overdose depend on the severity of the overdose and the promptness and effectiveness of treatment 2, 3, 4, 5, 6
- Some patients have recovered fully with aggressive treatment, while others have died despite treatment 2, 3, 6
- The development of a procedure for rapid measurement of diphenhydramine concentration in the emergency department may be beneficial in cases of overdose 3