Monica Sue Wood Haven't heard about it yet. But may be a topic of trial certainly.

Md. Israt Hasan Thank you for your 2 cents. I'm really quite surprised I can't find more data. It is a really simple thing to try. My anecdotal results were astonishing. I would never have imagined an antihistamine would help more than everything else I tried.

Monica Sue Wood There is very limited data because of very limited works on it. I think somebody should run a Double blinded placebo controlled RCT on this topic.

I had never really heard of it, nor seen it in any "ad hoc" protocol and, of course, used. It is true that neuropathic pain is refractory to standard analgesics and, in addition, it tends to become chronic ... therefore the treatment must be comprehensive and holistic: combining different types of analgesics (Pregabalin - lyrica-, opiate patches, opiates " minor "-tramadol-, capsaicin; corticosteroid blocks, muscle relaxants to break the" tension / pain "cycle; tricyclic antidepressants and, lastly," duloxetine "), but all this combined with a good cognitive / behavioral and physiotherapy intervention ... If such pain is still refractory, neurosurgical techniques (as in the case of trigeminal neuropathy) or more central techniques (implantation of a neurostimulator or periodic sessions of Pulsed Radiofrequency) can be used ... but Antihistamines?

Chronic itching and chronic pain share lot of peripheric and central sensitization, gabapentine can also be used for chronic itching, so antihistaminic could be a interesting medication for chronic pain...

Erwan Treillet Looking at other replies (e.g. Francisco Javier Gala 's), it just seems like no one ever considered the antihistamines and thus very little research has been done. Are you connected with anyone who might be able to do some studies? I am truly astonished at my personal experience with them. Like many physicians, all the other treatments came to mind and I used a number of them, but my pain decreased substantially with first topical then oral antihistamines. While shingles do tend to be time-limited and post-herpetic neuralgia occurs in about 3%, the immediate relief at 2 different times with 2 different medications by 2 different routes has me thinking these drugs deserve more attention. However, I'm no longer in a position where I could either do studies myself or pass the idea to a colleague. My fellowship mentor might have been quite interested in years past, but he is retired now and I'm not connected with the younger generation there.

Just a thought, but if you had relief from sinus drainage and an antihistamine, perhaps the pain you're getting isn't neuropathic but related to inflammation/pressure from your sinuses???

Chris Blatchley No--this was definitely shingles pain in my right thorax, ~T6 dermatome.

Dear Monica Sue Wood: I do not doubt at all that your pain will decrease or disappear (definitely?), But in the absence of a controlled, double-blind study on the matter, can you assure that this was not due to THE PLACEBO EFFECT? That, by the way, in any Clinic or Pain Unit they will confirm that precisely such type of pain is highly benefited by such EFFECT

I totally agree with Francisco's comments

The problem with treating pain is that one can get 50% reduction (or more) in pain from a placebo effect. It is possible that you can't find any data because there is no direct effect, though I more than agree that absence of evidence is not evidence of absence.... however your case would certainly be strengthened if you had a suggested mode of action!

I am confused why a sinus lavage should have a beneficial effect for thoracic shingles, other than placebo

More importantly, Benadryl has a local anaesthetic effect

From a Google search "Diphenhydramine hydrochloride (DPH) has numerous pharmacological uses in medicine. It is a first-generation, sedating, oral antihistamine. When topically applied, DPH has excellent anesthetic and antipruritic effects. DPH has also been shown to be an effective injectable drug for local anesthesia"

Chris Blatchley & Francisco Javier Gala : That is why I'm posting here. I am unable to get data myself and looking at the available studies, there is very little information. Yes, my experience is anecdotal. Yes, it could be coincident with regression of HVZ. Yes, it could be placebo effect. But again, the timing and degree of relief suggest something worth investigating. Who is up to the task?

Chris Blatchley Where do you get sinus lavage from? I never said anything about that. I used Benadryl cream on my thorax as an addition to Voltaren, Lidocaine, and Neurontin (all topical). When I ADDED the Benadryl, the relief was markedly better than the combination of other medications. As a SEPARATE issue, I decided to try ORAL Xyzal for my right maxillary sinus drainage (no pressure, no pain, just post-nasal drip that keeps me awake). When I tried it, I had another immediate, marked decrease in my shingles pain. So, again--2 different classes of medication, by 2 different routes, at 2 different times....and for different reasons. My goal here is not to debate my symptoms and relief, but to suggest an area of research that is sadly lacking and may have a lot of potential.

Suddenly I fee attacked!!

" Fast forward a couple of weeks and I'm looking to relieve some sinus drainage and I try Xyzal. Even better! I can't believe the relief I'm experiencing from these two medications." You are correct that I hadn't spotted that this was for the future, so I stand corrected on that. However it was introduced without other explanation!

As an MNPharm I'd made the assumption that you would have researched explanations of how it might reduce pain, but now you have an explanation.....

Indeed, Monica Sue, is VERY INTERESTING and worth investigating

See https://www.jpsmjournal.com/article/S0885-3924(01)00311-6/fulltext

Hey Monica, your experience was not a "placebo" effect. There is in fact growing research on the role of H1, H2, H3 (histamine) antagonists in neuropathy pain. Check this paragraph out I copied and pasted and I included the entire study. There is one medication showing a lot of promise (it's an H3) but it's approved for narcolepsy-still, it shows great promise for neuropathy pain...and, the research talks about some relief with H2 (more commonly known histamine antagonists)... so, you stumbled upon something very, very real. Here is the paragraph I copied. And I include the link to entire published (a recent publication by the way) research.

“The analgesic effectiveness of H3 receptor antagonists/inverse agonists was comparable to gabapentin and pregabalin first line treatments for neuropathic pain. Importantly, multiple examples of behavioural electrophysiological and molecular evidence strongly support the rationale for this neuropathic pain strategy particularly given their ability to modulate histamine levels as well as several neurotransmitters critical for chronic pain processing. Moreover the recent registered approval of pitolisant (Wakix) an antagonist/inverse agonist of H3 receptors for the treatment of narcolepsy in patients has opened the door for the potential use of H3 ligands for other conditions including chronic neuropathic pain.

Recent findings also suggest the use of centrally permeable, H2 receptor antagonist as promising new drug candidates for the treatment of neuropathic pain in view of their analgesic effects and metabolic stability. Here is the link to the research. Article Histamine, histamine receptors, and neuropathic pain relief

Andrew Banewicz