Can I mix benadryl and coffee?

In this short article, we will discuss possible interactions between caffeine and benadryl, as well as show real cases of poisoning by this drug.

Can I mix benadryl and coffee?

Officially, there is nothing to show that any interaction occurs when consuming caffeine and diphenhydramine together. However, it is always good to consult a doctor. Never take any medication without a prescription and medical advice.

What is Benadryl?

Benadryl®, whose active ingredient is the anticholinergic diphenhydramine (commonly used to temporarily relieve symptoms resulting from respiratory allergies or the common cold, such as runny nose and sneezing) causes dose-dependent toxicity. 

Clinical manifestations in the central nervous system (CNS) of anticholinergic intoxication include agitation, ataxia, confusion, delirium, hallucinations, seizures (although rare), and coma. 

Other manifestations in other systems include: mydriasis, tachycardia, hypertension, nausea, vomiting, decreased peristalsis, flushed skin, dry mouth, hyperthermia, spasmodic myoclonic movements and choreoathetosis (which can lead to rhabdomyolysis), urinary retention and, more rarely, insufficiency kidney from rhabdomyolysis.

Faced with this situation, the American Food and Drug Administration (FDA) issued, on September 24, 2020, a note warning about the complications resulting from the use of high doses of diphenhydramine. 

The FDA reports that it is investigating these reports and conducting a review to determine if additional cases have been reported and that it will update the public once they complete this review or have more information. 

In addition, he refers to having contacted the social network TikTok, strongly encouraging it to remove the videos from the platform and to be attentive to removing additional videos that may be posted.

Diphenhydramine hydrochloride is a first-generation H1 antihistamine with side effects

anticholinergics and sedatives. Antihistamines appear to compete with histamine for sites of

H1 receptor on effector cells. Thus, they prevent but do not reverse mediated responses only by histamine. 

The antidyskinetic effect of DIPHENHYDRAMINE in parkinsonism appears to be a consequence of central inhibition of actions of acetylcholine. In the form of an injectable solution, rapid onset of action occurs.

Diphenhydramine hydrochloride is widely distributed throughout the body, including the CNS. It is excreted unchanged in the urine, while the remainder is metabolized by the liver.

On the other hand, orally, after the administration of DIPHENHYDRAMINE, the maximum serum concentration is reached in 1 to 2 hours. Elimination is mainly urinary. 5 to 15% of the drug is recovered in the form unchanged, and 50 to 65% in the form of conjugated metabolites. 

The plasma half-life is about 6 hours. There is no information on the passage of the product through the fetoplacental membrane. Occurs excretion of diphenhydramine through breast milk.

Are there real cases of poisoning?

Widely publicized on the social network Tik Tok, the “Benadryl challenge” has instigated teenagers to consume high doses of this drug. Recently, a 15-year-old American girl from Oklahoma died after filming herself with hallucinations from an overdose of this drug. 

There are also reports of other teenagers who survived but were admitted to Emergency Departments for the same reason.

The FDA stresses that healthcare professionals should be aware that the “Benadryl challenge” is occurring among teenagers and alert their caregivers about it, in addition to considering the possibility of an overdose of diphenhydramine in a patient with an exogenous intoxication clinic. 

In addition, it recommends that consumers, parents and caregivers should store the drug diphenhydramine and all other over-the-counter or prescription-holding drugs away and out of the reach and sight of children, keeping them in locked places to avoid accidental poisoning by children and misuse by adolescents, especially during social isolation due to the Covid-19 pandemic.

Can you imagine finding out that one of the people you love the most actually wants to kill you?

This is what happened to American Therese Kozlowski who, although she filed for divorce from her husband, Brian, in June 2018, continued to live in the same house as him.

Brian even made her coffee every day and used the opportunity to mix in dangerous doses of diphenhydramine, an antihistamine used primarily to treat allergies and insomnia.

After a few drinks and a lot of sleepiness, Therese decided to install cameras in the house to see what Brian was doing. That’s how he discovered the poisoning.

The shocking footage shows the man breaking several pills and dropping them into his wife’s cafe before spinning to make the drug melt faster.

Therese moved out and notified her lawyer of the grim discovery. Authorities were able to seize the last coffee he made for her and found it contained 127 milliliters of diphenhydramine, about eight pills.


In this short article, we discuss possible interactions between caffeine and benadryl, in addition to showing real cases of intoxication by this drug.


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