how much diphenhydramine is an overdose?

I have severe allergy symptoms where at this point nothing helps it except for benadryl...I have to take two tablets every four hours and I am worried this may be harmful...If I don't do this my throat itches, eyes and even my face due to allergies. Sometimes I wake up in the middle of the night w/ my allergy symptoms and have to take more benadryl-and it doesn't even knock me out. I'm at a loss of what to do, if I don't take it I can't function and if I keep this up I'm worried it can potentially harm me...any suggestions out there??

I am currently getting over a head to tow poison sumac episode and have been taking diphenhydramine for its anti-histamine effects to reduce itching. I have averaged 14 - 25mg pills per day for the last 10 days (the urushi oil from the sumac got into my blood stream so it will take a while to be completely gone!) and have had no ill effects. That is 350 mg per day for 10 straight days with no side effects whatsoever.

I admit that I am a big guy and have an unusual body chemistry (I had a major surgery 4 years ago and their first attempt at putting me to sleep was uneventful, they said, "count backwards from 10", I finished a couple Sudokus and then they gave me more meds!!!)

Though, I doubt this thread is super-recent, I would like to say that I tale Diphenhydramine recreationally and I go anywhere from 150mg - 500mg and I'm fine. heavier doses can range anywhere from 700mg to (and I'm not sure about this one, but I have heard of it) 1500mg. In lower doses (100mg - 150mg), Diphenhydramine if used more as a sleep-aid. Higher doses creates a drunken state, It take approximately 500mg to make a rat OD, so 100mg for a full grown human is nowhere near enough to make him/her overdose. :-)

 i take 50mg benadryl every 6 hours along with 75mg zantac (or ranitidine) for hives that are ramping up as they usually do.  today i had to start a prednisone 60mg taper.  so, now, i am 'stacking' antihistamines.  that is, i have added either 1/2 or a whole zyrtec -which is 10mg-  every six hours to the benadryl and zantac.  sometimes i take the zyrtec with the other two drugs and sometimes i stagger. this seems to be working fairly well.  the dermatologist said they have, in the past, stacked as many as three different antihistamines to control itching.  i believe the next stack would be claritin.  

<-------Not a medical professional. I wouldn't recommend it to anyone because it is not very smart, but I take anywhere from 9-10 diphenhydramine capsules a night for sleep problems. I've been to numerous doctors and none of them suggested for me to keep doing it, but they also were not worried about overdose. The worst response I ever got was that it can give you hallucinations and at a high dose for a long period of time, can cause a permanent state of psychosis. It does cause other problems like dry mouth, throat numbness (due to dryness) and constipation. (Because the antihistamine dries everything out.) So far though, I haven't had any problems with it. I can't afford Rx strength sleeping pills, and the one time I used Ambien, it caused me to hallucinate and kind of made me crazy. Won't ever take it again. So I find it hard to believe that 100mg can cause an overdose. (Unless it's a small child or infant.) And for the ones that stated an overdose, I would think they may have taken Tylenol PM or something like that and actually had an acetaminophen overdose. That is all.

I was 16 when I overdosed on benedryl. I took 250 pills, granted I am here but it took my stomach being pumped and major hallucinogens. I could not speak even if I wanted to. Very lucky I am still here...

I'm just going to put it out there that I accidentally took 200mg and all that happened to me was a very long sleep. However, that doesn't mean to do that... I take 2 sleeping pills when I stay overnight at my boyfriend's house because of our 2 young cats that keep me up at odd hours of the night. One night I took 2 pills, blanked after my shower and took 2 more. I realized that I had done this when they kicked in and I felt like sleep wasn't an option but inevitable. Either why, yes, effects can and will vary from one person to the next but I can almost guarantee you'll be fine if once and a while you accidentally or purposefully take 2 instead of 1 pill. Don't make it a habit and don't press your luck. You did say a doctor prescribed them to you, why don't you ask your doctor about the risks involved and what that max dosage is that he/she recommends?

I have anxiety problems and i take 150 mg of it every night to at least go to sleep. i rarely can get a full 8 hours my average sleep time is 2-5 hrs 

When I was a teen, I would abuse benedryl on a nearly nightly basis. started with small does (10-12) and when i stopped my NIGHTLY intake was 60 in one dose, followed by another 40 2-3 hrs later to prolong my high. at that time i was 15-16 years old  5'11" and 255 lbs. yes its extremely hard to od and die, but i wouldnt worry about dying from the physical effects (applies to a healthy individual with no serious health problems) as i would the psychological effects, the halucinations can get very, very intense to the point the line between fantasy and reality is no longer easy to tell apart.  Which brings up the reason i stopped, i made a habit of not doing them when im alone so i tripped with my best friend, we were more dosed up than ever and a movie came on, it was scream btw, and both our trips went horribly wrong. the only difference was in my fear i hid in the closet for 5-6 hours.....my friend in his panic tripped and fell out the 4th story window of the apt complex onto the sidewalk below, and was killed instantly. bottom line, always take into consideration on how any drug you use, legitly or recreationally, reacts with your whole body.

I am an 18 year old 165b athletic man.  I took 400mg of benadryl and half a bottle of nyquil just b/c one of my friends told me they tripped out fat.  I took it near 12 in the afternoon and sh*t was crazy.  i was pale, hella dry mouth, ringing or voices of my friends or family was what i was hearing and my vision definently blurred. It felt good at first so i took more and more and i tried having conversations with my family and friends and i would literally forget what i was talkin about half sentence in.  I saw my best friend outside on my swing wen i was smoking a ciggarrete, but he wasnt there.  I pictured my aunt and heard her voice in the backyard along with my moms even though the only other person at my house was my dad who was asleep.  The trip started at 12 and went till the next day or until i fell asleep.  i played soccer at the park wit my friends and my eyes were like ALIEN EYES! these mutha fuckas were so diolated and my friends thought i was thizzing (ecstacy) but i told them i jus took hella benadryl.  I acted sane for the most part except wen i would forget what i was saying. also during soccer my legs felt like weights, but anyways the day went on and i blazed super fat (marijuana) thinkin it would help and it kinda did cuz it was a feeling that i am really used to over hear in california. went to a party that night and did very well at beerpong.  what came next was the hallucinations.  I started freaking out every two seconds as if ther were spiders on me so i had my dad pick me up.  My head started to itch and my pubes too and wen i looked at my hair in the mirror i would see little white lice or tick things all on my pubes and hair.  I immediately took a shower but it didnt help i saw these lice crawling under my skin. i shaved pretty much all my body hair but my head and told my sister that i wanted to get it checked out at the emergency room.  I volunteered to go to the e room b/c of how screwed up i was. wen we got there, the doctor said there was nothin but 1 or 2 bug bites.  after hearing this i wasnt about to incriminate myself and be like NOOO THERE EVERYWHERE!! So i said that i was biten by black widows earlier in the day which he believed. wen i left the hospital i snapped out of it instantly so i wouldnt get myself into any sketch trouble. and that was that. I felt every side affect listed above on overdosing on benadryl. Do not take hella benadryl at once i dont give a sh*t how old or how big you are, this sh*t is unlike any other drug induced state that i have ever experienced in my life and even crazier then shrooms.  Use with caution.  Lesson learned.

I was recently in the midst of a major depression.  During this time, I took 425 mg of diphenhydramine (8.5 of those pills you took) and I survived relatively unharmed.  400 mg is considered the first level of severe overdose in this drug where 600 mg is considered extremely dangerous.  100 mg won't hurt anyone.  It will only make you extremely drowsy (depending on your tolerance to the drug) and maybe give you cotton mouth.  Nothing too serious.

just took 8 25mg and a piece of shroom. i wiegh 200lb. this is my first time. how much should i feel?

This is bad stuff whether it is bendadryl, tylenol pm or advil pm.  My situation was accidental.  It can make you hallucinate and can cause you to be put in life altering situations.   I was lucky and had someone home with me or god only knows what I would have done to myself.  I also am fortunate to have good friends that were there for me.  It doesn't only last hours it can last days.  I fell down some stairs in my house and cracked my head on the tile floor!  I am lucky I didn't get a bleed in my brain and die because of course I didn't go to the hospital!!!  IT WAS HORRIBLE.  I will avoid the stuff from now own because I have never had a drug scare me so bad!  If you think all of these post are a joke you should think again.  I assure you, you don't want to be put in the position to experience the sypmtoms on your own. 

I know this is a very old question, but 100mg is not an overdose. If you don't regularly take it it might make your heart race, but that also could have been from  you freaking out that you OD'd and psyching yourself out. I have a condition called mastocytosis, (my body has too many mast cells, the cells in your blood that make histamine). I frequently have allergic reactions to seemingly nothing at all. I have to take 100mg of benedryl every night, along with 2 zyrtec, 2 claritin and a singulair to keep me from going into anaphylaxis (which I still do anyway occasionally.) However, to the people that are posting that they use benedrul as a sleep aid, I would advise you reconsider this option. Medical studies have shown that people who have taken benedryl react even more slowly than people who are intoxicated. If you don't have to take it, don't. There are other much more safe options to helping insomnia than by using OTC drugs.

Due to anxiety that I have I have taken benedryl to give me an excuse to why I might feel weird.  I could then blame it on the benedryl.  I have taken 3 doses of 200 mg (8 25 milligram tablets) for about 5 years.  been trying to go off of it now.  But I get seizure like jerks that I cant control lately.  Some  seizures I have blacked out on and a few other just had to let my body jerk while I lay helpless.    It seems worse when I take the benedyrl.  I dont quite understand why I do this but I do and I am slowly getting more symptoms as I lower dose.  Scary stuff.  I had been blaming it on getting off of xanax because seizures can be a symptom of withdrawl.  I have not taken any xanax for 5 days but have benedryl and still have jerks.