Antihistamine tolerance issues.

[Dread calm]

Hey guys, i use promethazine quite regularly for opiate potentiation, and when I'm out of Benzos i use diphenhydramine to get to sleep. But now it's got to a point where i can take 200 mg of diphenhydramine and not even be drowsy, same with promethazine. I know it's clearly tolerance so my question is, how much of a break from these do i need to take in order to be able to get the sleep aid effects back?
Thanks in advance.

 

[Brian242]

Use White Grapefruit juice to potentiate your opiates and wait a month or two before using DPH or Promethazine .

 

[debaser]

Be careful with antihistamines, don't go overboard. They can have long term nasty side effects like the old antipsychotics.

 

[SerotonergicHaze]

Indeed, especially Promethazine which is very similar in structure to the infamous antipsychotic Thorazine/Chlopromazine. Promethazine in excess can cause Tardive Dyskinesia and other movement disorders, seizures, and in extremely rare cases Neuroleptic Maliglant Syndrome

 

[NeighborhoodThreat]

I'm going to repeat what SerotonergicHaze and loulou said, be careful with high dose promethazine use. Your best bet is to switch potentiators and take a break from antihistamines to get your tolerance down. I'd say at least a week or two (you can try a week and see if that works).

Antihistamine tolerance sucks, but don't attempt to fix it by just taking more antihistamines. Take a nice break and your tolerance will drop.

 

[Dread calm]

Blimey, i never realised promethazine had so many adverse effects. Noted, I'll give it a rest for a few weeks.

 

[paranoid android]

It can take a very long time for tolerance to anti-histamines and anti-cholinergics to go down. I know a person that took 75-100mg's of diphenhydramine atleast 3 times a day for almost a year for their allergies. They became so tolerant to the diphenhydramine that they could take 150mg's and get absolutely none of the anti-cholinergic effects and only very slight anti-histamine effects. This person also took quite abit of hydroxyzine (a very good anti-histamine for opioid potentiation with no anti-cholinergic effects) along with the diphenhydramine when their allergies got really bad.

This person eventually ended up in the hospital due to a very severe allergic reaction of unknown origins. The doctors where amazed at how tolerant they where to the effects of the anti-histamines they where getting in a drip. Ive often wondered if perhaps their overuse of anti-histamines contributed to the allergic reaction. In anycase it was a good 3 months before their tolerance to anti-histamines dropped back down to baseline. I have noticed that seroquel has made me more tolerant to the effects of diphenhydramine which makes sense due to quetiapine's rather strong anti-histaminic effects.

So i would say the best advice is to lay off taking anti-histamines for atleast a month and if you start taking them again don't take more then the recommended dose due to the side effects mentioned above. Too much diphenhydramine can cause a very unpleasant delirium and too much promethazine can cause that as well as the side effects associated with anti-psychotics due to promethazine's very mild dopamine antagonism.

 

[RobotRipping]

I've been taking anti-histamines for years for sleep, allergies and sometimes potentiation. My tolerance hasn't gone up at all though. I could still take 50mg of diphenhydramine and get nice and sleepy. Are some of these adverse effects particular to promethazine or do they also apply to other 1st gen AH or later gen AH as well? I definitely do not want any issues with dyskinesia

 

[pbuilder]

Use White Grapefruit juice to potentiate your opiates and wait a month or two before using DPH or Promethazine .

the thing about anti-histamine's like diphenhydramine before opiate consumption is that they not only potentiate (sedation mostly), but they also get rid of a lot of the negative side effects like nausea and itching. I use DPH just because it completely gets rid of the nausea.

 

[paranoid android]

I've been taking anti-histamines for years for sleep, allergies and sometimes potentiation. My tolerance hasn't gone up at all though. I could still take 50mg of diphenhydramine and get nice and sleepy. Are some of these adverse effects particular to promethazine or do they also apply to other 1st gen AH or later gen AH as well? I definitely do not want any issues with dyskinesia

Adverse effects like Tardive dyskinesia and Akathisia which happen with anti-psychotics are only adverse effects related to promethazine as diphenhydramine has no anti-psychotic properties. Promethazine is a Phenothiazine which means it's in the same class of drugs as chlorpromazine aka Largactil aka Thorazine which was a widely used anti-psychotic before the atypical anti-psychotics like risperidone, seroquel, zyprexa, Ziprasidone (geodon/zeldox), etc where developed. Ive never had promethazine (it's OTC here but no pharmacy seems to stock it ) before but i have had chlorpromazine and Levomepromazine both of which belong to the Phenothiazine class of anti-psychotics. I was given them for nausea and sleep and they worked well enough for both. Good old Thorazine is probably the best anti-nausea drug Ive had. Too bad it's side effects can be pretty bad due to it's dopamine antagonism. You shouldn't have any of these problems with promethazine if you stick to the recommended dose as it's dopamine antagonism is very weak.

As for diphenhydramine it won't cause any of the side effects like tardive dyskinesia or akathesia as it has no dopamine antagonism. But if you take high doses you run the risk of getting anti-cholinergic delirium which is absolutely awful. I once took 25 50mg pills of dimenhydrinate (Dramamine,Gravol) which is almost identical to diphenhydramine to get "high" from it and i was totally delirious for about 8 hours. It was the worst drug experience of my life and that is saying something 8( . But if you stick to recommended doses which is no more then 50mg's at a time you'll be fine though I'm not sure if really long term medical use can cause long term effects.

I take diphenhydramine alot to potentiate opiates (as well as for my allergies) because it really adds to the nod especially when you take a benzo with the opiate and diphenhydramine. I am also probably the only person on earth who actually enjoys taking Thorazine with my morphine lol. It feels like a really drowsy anti-histamine to me but my brain is abit weirder then most peopls

 

[Dread calm]

So, would the use of amitriptyline as a sleep aid cause cross tolerance to the anticollinergic effects of the antihistamines? If so, that would also explain a lot.