Spicy Approach to Shingles -- Full-Length Doctor's Interview

Ivanhoe Broadcast News Transcript with
Michael Tuchman, M.D., Neurologist/Psychiatrist,
Palm Beach Neurological Center, Palm Beach Gardens, Florida,
TOPIC: Spicy Approach to Shingles

Give me the background on the shingles virus.

Dr. Tuchman: As kids, we get chicken pox. Our bodies fight it off, but the virus remains in us forever. It hides in the nervous system. About 40, 50, 60 years after the infection, for many people, the immune protection fails and now the virus is free to come out again. When it comes out again, it doesn’t come out as a whole rash, it comes out of just one nerve in the spinal cord -- one nerve -- and that’s shingles. It clears within a week in most people. In about 20 percent, it doesn’t clear. The rash goes away, but the pain that the nerve damage causes persists. That’s post-herpetic neuralgia. That’s what we’re trying to treat.

What makes this capsaicin study so special?

Dr. Tuchman: What makes it different is that for many of us, including me, I used to think that the whole problem with post-herpetic neuralgia was the scar tissue that was formed with that second eruption at the level of the spinal cord, or the root entry zone of the spinal cord, where the nerves in the spinal cord meet. So, for that reason, you would feel that treatment should be aimed at that area. That’s where most of the medication we’re using and new research is given -- medications that work in the spinal cord or above to control the pain. But, there’s also another theory that says that a lot of this is happening because of the damage that the nerve experiences at its end, right at the very end, right at the skin. The treatments we’re using, such as capsaicin, are a way of enervating, of diminishing the ability of that end tip of the nerve from being irritable. It’s a unique thing because we’re using an extremely high dose of capsaicin, 400-times higher concentration than is available in anything on the market now, and we’re aggressively enervating that tissue for 60 minutes. Then we remove the patch, and what we see in many of these patients is that the pain relief lasts month after one treatment, and that’s interesting news.

How does the capsaicin do that?

Dr. Tuchman: That’s a very good question, and I’ll try to answer it the best we understand it now. There appears to be a need in many of the post-herpetic neuralgia patients, the shingles patients, a need for the nerve to initiate the wrong message for the pain to then be sent upstream to the brain. And that irritable, damaged nerve ending in the skin, if we can basically eliminate the tip ends of the nerves with capsaicin, which actually drops down just below the skin level, doesn’t go into systemic, it appears to allow the nerve to sort of cut back a little bit, sort of guide back a little bit. Then we think they may grow back in a healthier fashion. That’s the theory behind it. What we know, what clinically has happened is that the irritated nerve endings have quieted down tremendously when treated for one hour with this very high-dose capsaicin, and that’s very interesting. So, whether this turns out to be the only treatment required for our patients, or if this is going to be something that we mix with our existing treatments, which are tablets that cuts down the nerve impulse of the spinal cord, we don’t know. We’ve looked and both and both may be an option for some patients. Some patients may need just this; some may need a combination of something to tone down the spinal cord and something to tone down the message to begin with in the skin.

Does this treatment kill the nerve ending?

Dr. Tuchman: I think we are reducing the irritability of the nerve ending. I don’t think we are killing it because it's still a viable nerve, but we’re reducing the ability for it to act and to behave, to do what it normally would be doing, which is to send this inappropriate message upstream. Then when it sort of returns to function, it seems to return in a healthier way. We’re still learning, but we know the patients feel because we check sensation, sensation is still there, but the pain isn’t. Very interesting. Now, it isn’t that the pain completely goes away, but if you diminish it enough and the patient can return to work and do whatever they’re doing.

Could you give an analogy for what this treatment does? It seems to me that you’re training the nerve not to act or to send messages on inflammation, but are still able to be sensitive to touch and other types of pain?

Dr. Tuchman: Capsaicin seems to be somewhat selective for the nerves that are the irritant nerves. When you think about it, when you eat a chili pepper, you get numbness around your mouth. That numbness wouldn’t keep you from feeling pain -- if somebody punched you in the nose or punched you in the mouth, you would still feel it -- but there’s clearly a sensation around the tongue and the mouth for the brief time after you eat a chili pepper. How that’s happening seems to be a selective ability of the capsaicin molecule for working more on one kind of nerve ending than others, and that’s just serendipity, just luck that it works like that, but we’re taking advantage of it.

You touched on the chili peppers. Is that an active ingredient?

Dr. Tuchman: Capsaicin is the active ingredient in chili peppers. What makes chili peppers burn is capsaicin in very low doses. It’s really kind of interesting because it’s the application of sort of nature onto science. That’s always an interesting thing. So, I guess the answer has been that we just didn’t know how to go ask for it.

What are the origins of this type of treatment?

Dr. Tuchman: That’s a very long story, but I can assure you that the concept of interfering with irritated nerve endings has been there for a long time. We knew that if we could do that, we would buy some improvement, but the available capsaicins, the available chili pepper extract, did very little for a very short time. What’s different about this particular way of delivering it is that they’ve managed to get a very high dose of this stuff onto a patch that you’re going to apply to the area of interest for an hour, hour and a half, and then remove. During the time of treatment, imagine having a 60-minute exposure to a chili pepper in your mouth. It’s going to be intense. And it's sore, and sometimes the patients may need to have an oral pain medication for an hour or something, but it’s only for an hour. These are people who can’t function, so clearly it’s a very good bargain that we can do and our patients seem to find it helpful.

Is this drug extracted from chili peppers?

Dr. Tuchman: Well, it’s made chemically, but it’s the chili pepper extract. It's capsaicin, but now it's being made directly.

Are there any side effects?

Dr. Tuchman: The first and most important side effect is the fact that there’s definitely local irritation during the time of treatment. The skin may turn red, and it's painful and discomforting during the hour of treatment. But, we haven’t seen any long-lasting problems. Now, we’re very early on, but one of the good things in our study is that we looked at blood levels to see if capsaicin got into the bloodstream when it was applied in such a high dose to the skin. It did not, and that’s very good. We only want a local application. We wouldn’t want to be worrying about this stuff getting in the bloodstream. As long as the skin is intact, and it is, and you apply it, it only goes just into the dermal layer and stops there. It doesn’t get in systemically. Therefore, the likelihood of long-term side effects is quite unlikely because you’re not getting a systemic effect in this medication. It is a local irritation that’s gone when you remove the patch.

How many people could benefit from this if it’s approved?

Dr. Tuchman: You’ve got to think of how many people have post-herpetic neuralgia, this ongoing shingles. Our best estimates in the United States are between half a million and a million people at any one time. It’s a disease that affects elderly. The older you are, the most likely you are to get it, but early again is 50 and above. We’re not talking about 90-year-olds, OK? So, you’re probably at least conservatively half a million people that have it today. Of those, most are undertreated or untreated because with the exception of one or two medications that do help, nothing else seems to help and even those from which the medication is helping, we only are getting partial responses. So, if we have something here that can add to that, give us another partial or complete response, that’s a lot of people that would benefit. I would imagine that at least two-thirds, and I’m guessing because this is early data, but probably two-thirds of the people that are treated with this will benefit modestly or significantly. That’s an extensive number.

Explain why it’s too early for excitement.

Dr. Tuchman: We have a very small number of patients that have been studied, and it may be a fluke. I doubt it, but it may be a fluke, and it is very important that we extend the number of patients in our studies, continue our double-blind studies which we are doing here. We use several different treatments for post-herpetic neuralgia. This is one of several that we’re looking at, and I think we need to remember that first of all, I doubt that everybody is going to benefit, and even if significant numbers of people benefit, we may find that the numbers vary as we continue to study this, and I suspect that for many patients, we’re going to have to offer them a cocktail of treatments in which we offer them perhaps a patch, plus an oral medication, etc. I would like to see a few hundred patients treated before we get even more comfortable, and I think we’re moving in that direction. We’re currently doing a study that will bring a few hundred patients into our database nationally, and that will help. So, we’re still very early on.

Is there anything else you want to mention?

Dr. Tuchman: The only other thing you may want to mention is that because it’s a patch and it’s an intense capsaicin application, some patients with this cannot benefit. For example, shingles can affect the face and by definition, we can’t treat there with a patch. So, there will always be a need for other treatments, but from the neck down, this is an excellent treatment.

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END OF INTERVIEW

This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc., or any medical professional interviewed. Ivanhoe Broadcast News, Inc., assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.

If you would like more information, please contact:

Palm Beach Neurological Center
http://www.pbneuro.com