Benadryl, also known as diphenhydramine, is an antihistamine commonly used to treat allergy and cold symptoms. However, it can lead to serious side effects, especially when not taken correctly.
A recent review published in the World Allergy Organization Journal suggests reevaluating the drug's safety, stating that its risks now surpass its benefits.
The active ingredient in Benadryl, diphenhydramine, was approved by the FDA in 1946, before current stringent testing standards were established.
Since then, severe side effects such as sedation and impaired concentration have been widely documented. In contrast, newer antihistamines with safer profiles like Allegra (fexofenadine) are now more commonly available.
"While diphenhydramine is perceived by consumers to be a 'safe' over-the-counter drug, it’s important to recognize that like all medications, it has side effects including drowsiness and poor concentration," said Kelly Johnson-Arbor, MD, medical toxicologist at MedStar Georgetown University Hospital.
Diphenhydramine has also been associated with potentially life-threatening complications and should be used strictly as directed on the package label.
The following list outlines some of these potential severe side effects:
While Benadryl is sometimes employed for insomnia, it can cause drowsiness in those using it for other purposes. Older research suggests that its impairment may affect driving more severely than alcohol for certain individuals. Additionally, diphenhydramine, while a sedative medication, can paradoxically induce agitation in some people, particularly children.
Benadryl users have also reported headaches and dizziness, with excessive usage potentially leading to confusion or hallucinations.
"The chronic use of first-generation antihistamines like diphenhydramine has been linked to an increased risk of developing dementia," Johnson-Arbor mentioned.
Blurred vision and dry eyes are also common side effects. Individuals with glaucoma should consult a healthcare provider before consuming Benadryl due to potential risks including eye pain or impaired vision.
Some people may experience bladder problems while taking Benadryl, requiring immediate medical consultation if urination difficulties arise.
The risk of serious consequences such as cardiac arrest, coma, seizures, and even death exists if large doses are ingested. Notably, multiple fatalities have occurred in recent years due to the "Benadryl Challenge" on TikTok.
"Exceeding recommended dosages can result in sleepiness, confusion, and concentration difficulties, particularly among children and elderly individuals," Johnson-Arbor stressed.
First-generation antihistamines like Benadryl penetrate the blood-brain barrier more easily than newer options. Modern alternatives including Zyrtec (cetirizine), Claritin (loratadine), Allegra (fexofenadine), and Xyzal (levocetirizine) are often preferred due to their reduced drowsiness-inducing effects.
"These safer, second-generation antihistamines offer equally effective relief without the sedative or cognitive side effects," explained Clifford Bassett, MD, an allergist at NYU Langone Health.
Individuals requiring chronic symptom management are advised to consult with healthcare professionals to identify triggers and determine the safest medications.