What are the Signs of a Diphenhydramine Overdose?

Article Details
  • Written By: Meshell Powell
  • Edited By: Melissa Wiley
  • Last Modified Date: 11 September 2019
  • Copyright Protected:
    Conjecture Corporation
  • Print this Article
Free Widgets for your Site/Blog
U.S. companies first sold energy drinks in the early 1900s; they contained radium, which causes radiation sickness.  more...

October 19 ,  1987 :  The Dow Jones experienced its second-largest percentage drop in history.  more...

Diphenhydramine is a type of medication known as an antihistamine. This type of medication is typically used to treat allergic reactions such as hives and itching. If a person takes more than the recommended amounts of this medication, it could cause a potentially fatal diphenhydramine overdose. Some of the symptoms that may indicate the possibility of a diphenhydramine overdose include weakness, seizures, or hallucinations. A suspected diphenhydramine overdose should be considered a medical emergency.

Early signs of a diphenhydramine overdose may include nausea, stomach pain, and dry mouth. The patient may also experience an inability to sweat or urinate. The affected person may appear to be unsteady or may have difficulty making normal body movements. Rapid heartbeat, extreme drowsiness, and skin flushing may also be present. Even if the symptoms seem mild, it is important to seek immediate medical attention in order to prevent the possibility of developing severe complications.

Neurological indications of a diphenhydramine overdose may include confusion or agitation. The patient may also appear incoherent and may not be able to focus or comprehend well enough to hold even a simple conversation. More disturbing signs may involve the presence of hallucinations or delirium. The caregiver may need help getting the patient to the nearest hospital if these symptoms are present. It may be wise to call emergency medical personnel to transport the patient to the hospital.


Whenever possible, the caregiver should try to gather some information that will be helpful to the medical staff. Emergency personnel will likely ask how much of the medication was taken and the time it was ingested. It is helpful to know the general weight of the patient, the patient's age, and the overall health of the patient. This information is not absolutely necessary, and attempting to obtain this information should not prevent the caregiver from calling for medical help immediately.

Treatment for the diphenhydramine overdose will begin as soon as the patient arrives at the hospital. Activated charcoal may be given in an effort to absorb some of the medication from the body. A small tube known as an IV may be placed in a vein so that medications can be quickly delivered directly into the bloodstream. In some cases, the stomach may be pumped or oxygen therapy may be needed. With proper medical care, a diphenhydramine overdose is rarely fatal, and a complete recovery generally takes only a day or two.


You might also Like


Discuss this Article

Post 4

About nine months ago, I had a grand mal seizure. I didn't remember it, woke in the hospital and was freaking out. I'm pretty sure it was from me overdosing on diphydramine. I've been addicted for several years to it for it helping me get to sleep, but its grown out of control to where I take it for helping me sleep and the high feeling is really hard to come off of. I did for about three or four months after the two seizures I had, and nobody knows if it was from the dp. It can ruin your life. Don't ever think about taking it if you're reading this, because like me, you could get really dependent on it.

Post 3

I once saw someone with Benadryl overdose in the ER. He was twitching, had huge pupils and swelling underneath his eyes. He looked awful and I'm sure felt awful too.

Post 2

@ankara-- If you don't feel well and think you might have overdosed, definitely go to the hospital or call the poison control center.

Usually, in the case of an overdose, many of the symptoms mentioned in the article will be seen. Heart rate can increase and concentration will be bad, but you will probably also have vision problems, eye pain, pupil dilation, involuntary actions and hallucinations.

It's better to see a doctor even if you're not sure because overdose symptoms can hit very suddenly and you might not be well enough to call an ambulance. The damage from diphenhydramine hydrochloride overdose can linger for weeks and even months. So it's better to be safe than sorry.

Post 1

Isn't diphenhydramine prescribed even for babies? I had no idea that it can cause these kind of side effects in high doses.

I'm currently taking diphenhydramine hydrochloride. I think I may have taken an extra dose. I couldn't remember if I took it during lunchtime or not. I've not been able to concentrate on my work for the past few hours. My heart rate has also increased. The drug description includes increased heart rate and difficulty concentrating as side effects but these are also signs of overdose.

So how do I know if what I'm experiencing are side effects or signs of overdose? Should I go to the hospital?

Post your comments

Post Anonymously


forgot password?