Too much Diphenhydramine

[Lightning-Nl]

So, I took (I think) 400 milligrams of DPH a couple hours ago and now I'm feeling just awful. It has induced horrible restlessness, pretty bad vertigo, and mild hallucinations.

I know DPH is taken as a deliriant, however, that was not what I was trying to do. I used DPH to potentiate the hydrocodone I have right, but I didn't realize that the DPH pills I have we're 50MG's a pill - rather than 25 like it usually is.

Anyways, I feel so awful right now that I can barely even move. Can any tell me how I can stop this? Or do I just have to wait it out?

Thanks guys! I appreciate it!

 

[NeighborhoodThreat]

You have to wait it out sadly.

Next time be more careful about overdosing on antihistamines...

 

[Corazon]

You have to wait it out sadly.

Next time be more careful about overdosing on antihistamines...

this.


I've found these to be really shitty drugs in my own experience. If you are naive to the diphenhydramine, and concurrently taking an opiate, a small dosage (1-3? of the standard pills) makes you drowsy. With the opiates it kind of feels like a comfortable sleepy 'nod'. Tolerance to the drowsy feeling of diphenhydramine builds rather quickly. Without opiates, taking more than the minimum dosage tends to make me have restless legs and side effects. The scientific method of action is not really something that you would want to go on with your brain as far as clear, intelligent thinking. I personally would not even take this for allergy.

 

[Lightning-Nl]

Well...I have an update.

I was confused as to why Diphenhydramine was making me feel so awful, especially since I've taken way higher doses of DPH before. So, I expected all the symptoms to fade away 8-12 hours later (this is DPH's half-life) and its now been 18 hours later and I have felt very little change. The other times I have take. Higher doses of DPH, it had its own specific feeling. However, this time, it felt like I was on a higher plateau dose of DXM. (Meaning the effects felt very serotonergic rather than anticholinergic)

Something I forgot to mention is the fact that I am currently on 60MG's of Paxil a night. And last night, because I wasn't thinking, I popped an extra 30MG's. so in total, I took 90MGS of controlled release (24 hour) Paxil, 10MG's of Norco, and 450ish MG's of DPH.

I have come to learn in the past few hours that Diphenhydramine is actually a potent non-selective serotonin reuptake inhibitor. It accomplishes this by block the serotonin transporters (SERT) Paxil also has this same effect. It's selective, but its also a potent reuptake inhibitor. Paxil (just like grapefruit juice) blocks all P450 Cytochrome enzymes.

It just so happens that Diphenhydramine, Paroxetine, and Hydrocodone are all metabolized by the P450 system. That's good for the hydro due to the fact that higher plasma levels can build up - but very bad for diphenhydramine and paroxetine.

Due to the fact that I had such a high dose of Paxil and such a high dose of DPH, the doctor at the emergency room told me that I had induced "Serotonin syndrome." He left the room for a second, and came back with two syringes. The first intrevenous injection he gave me was "Chlorpromazine" - an antipsychotic that has very potent antagonizing effects at all 5-HT receptors. Within 10 seconds of he giving me that, I was so tired I could barely keep my eyes open. It had instantly removed my vertigo, but I was still extremely agitated and aching really bad. So, the second intevrnous injection he gave me was "Lorazepam" which is a pretty potent benzo.

Within 10 seconds of getting that, I was extremely relaxed, my anxiety was all but gone, and my muscles didn't hurt anymore. Within around 2 minuets after that - I was asleep. I woke up around 15 minuets ago and decided I'd post this.

I'll try to add whatever I can tomorrow.

 

[paranoid android]

Well...I have an update.

I was confused as to why Diphenhydramine was making me feel so awful, especially since I've taken way higher doses of DPH before. So, I expected all the symptoms to fade away 8-12 hours later (this is DPH's half-life) and its now been 18 hours later and I have felt very little change. The other times I have take. Higher doses of DPH, it had its own specific feeling. However, this time, it felt like I was on a higher plateau dose of DXM. (Meaning the effects felt very serotonergic rather than anticholinergic)

Something I forgot to mention is the fact that I am currently on 60MG's of Paxil a night. And last night, because I wasn't thinking, I popped an extra 30MG's. so in total, I took 90MGS of controlled release (24 hour) Paxil, 10MG's of Norco, and 450ish MG's of DPH.

I have come to learn in the past few hours that Diphenhydramine is actually a potent non-selective serotonin reuptake inhibitor. It accomplishes this by block the serotonin transporters (SERT) Paxil also has this same effect. It's selective, but its also a potent reuptake inhibitor. Paxil (just like grapefruit juice) blocks all P450 Cytochrome enzymes.

It just so happens that Diphenhydramine, Paroxetine, and Hydrocodone are all metabolized by the P450 system. That's good for the hydro due to the fact that higher plasma levels can build up - but very bad for diphenhydramine and paroxetine.

Due to the fact that I had such a high dose of Paxil and such a high dose of DPH, the doctor at the emergency room told me that I had induced "Serotonin syndrome." He left the room for a second, and came back with two syringes. The first intrevenous injection he gave me was "Chlorpromazine" - an antipsychotic that has very potent antagonizing effects at all 5-HT receptors. Within 10 seconds of he giving me that, I was so tired I could barely keep my eyes open. It had instantly removed my vertigo, but I was still extremely agitated and aching really bad. So, the second intevrnous injection he gave me was "Lorazepam" which is a pretty potent benzo.

Within 10 seconds of getting that, I was extremely relaxed, my anxiety was all but gone, and my muscles didn't hurt anymore. Within around 2 minuets after that - I was asleep. I woke up around 15 minuets ago and decided I'd post this.

I'll try to add whatever I can tomorrow.

It sounds like anti-cholinergic toxicity to me and for one thing they never use chlorpromazine aka Throrazine to treat serotonin syndrome. Risperidone is a much more potent serotonin antagonist i think anyway. Cyproheptadine is the drug of choice for serotonin syndrome. Chlorpromazine is a strong anti-cholinergic in it's own right so it would add to the anti[-cholinergic effects of the diphenhydramine. I know from personal experience that benzos work wonders for treating anti-cholinergic toxicity so id imagine the lorazepam is what helped calm you down.

 

[Lightning-Nl]

It sounds like anti-cholinergic toxicity to me and for one thing they never use chlorpromazine aka Throrazine to treat serotonin syndrome. Risperidone is a much more potent serotonin antagonist i think anyway. Cyproheptadine is the drug of choice for serotonin syndrome. Chlorpromazine is a strong anti-cholinergic in it's own right so it would add to the anti[-cholinergic effects of the diphenhydramine. I know from personal experience that benzos work wonders for treating anti-cholinergic toxicity so id imagine the lorazepam is what helped calm you down.

It might have been Risperidone. He just said it was the most common antipsychotic used intravenously. When I searched for that on google, most of the results said that would be chlorpromazine.

 

[paranoid android]

It might have been Risperidone. He just said it was the most common antipsychotic used intravenously. When I searched for that on google, most of the results said that would be chlorpromazine.

Well risperidone ain't used IV it's only given in IM injections as far as i know. I think haldol is given IV more often then but usually these drugs including Thorazine are given IM as they all carry a risk of severe hypotension if used IV. They don't use these medications for serotonin syndrome and i doubt that was what you had in anycase. It sounds exactly like the symptoms of anti-cholinergic toxicity of which IV lorazepam would work fine for.

For serotonin syndrome they would use Cyproheptadine unless the doctor was a total fucking moron who had no clue as to what he was at. Which happens more often then not sadly enough . If i had not looked up what medications that doctors have prescribed to me over the years did and interacted with i could very well be dead now.