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CME Dermatology

Vehicles Matter: Choosing the Right Type of Topical Medication for Skin Disorders

Tracey Vlahovic, DPM

Tracey Vlahovic, DPM discusses the many vehicles for drug delivery available and the optimal use for these vehicles in podiatric medicine.

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Goals and Objectives
  1. Understand why vehicles are an important component of dermatology
  2. Summarize the types and potencies of topicals for inflammatory skin conditions like psoriasis and dermatophyte infections
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  • CPME (Credits: 0.5)

    PRESENT eLearning Systems, LLC is approved by the Council on Podiatric Medical Education as a provider of continuing education in podiatric medicine.

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    Release Date: 03/16/2018 Expiration Date: 12/31/2018

  • Author
  • Tracey Vlahovic, DPM

    Associate Professor of Podiatric Medicine and Orthopedics
    Temple University School of Podiatric Medicine
    Philadelphia, PA

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    Tracey Vlahovic has disclosed to be a consultant/advisor for Merz and Quinnova, and also has disclosed receiving compensation for service on advisory board from Merz

  • Lecture Transcript
  • TAPE STARTS – [00:00]


    Male Speaker: Our next speaker is Tracey Vlahovic. She is currently an associate professor at the Temple University School of Medicine in Philadelphia. She’s board certified in foot surgery by the American Board of Podiatric Surgery. She was the first podiatrist in the US to complete a fellowship in podiatric dermatology at St. Luke’s Hospital. Speaking of making the career that you want to have.

    She’s lectured extensively across the US. She’s spoken many times at our meetings. And I would point out that she’s also one of the best teachers in podiatry. You’ll really enjoy her teaching style. So please welcome Dr. Vlahovic with me.

    Tracey Vlahovic: Thank you, that was really kind. Okay, so if I said to you, “What do you use for post-operative pain?” You would probably say, “Well, in residency, this is what’s indoctrinated into my head.” I can still tell you what some of my attendings used for various procedures. I can tell you what my derm-attending told me to use for everything. But the reality is, is when you’re in practice, that’s not always the case.

    So one of the things that I felt I didn’t learn in podiatry school and at times, was confusing to me during my dermatology fellowship were vehicles. And it’s something that – I think it’s really important that as you go out and start treating patients you think about.

    So certainly, this – the learning objectives are; understand why vehicles are important in dermatology, summarize the types of and potencies of topicals inflammatory skin conditions and psoriasis and even dermatophyte infections.

    So really, the art and science of dermatology. First of all, you have to know what your diagnosis is, right? But you have to know which medication to choose. And that sometimes, is the hardest part. You know, think about – again, you might have in your head, ‘well triamcinolones 0.1% works for everything.’ But that’s not always the case. The old rule in dermatology is, if a lesion is dry, wet it. And if a lesion is wet, make it dry. That has been abandoned. Get that out of your head. Whoever has taught you that, we don’t follow that anymore.

    What a vehicle can do is it can stop or reduce transepidermal water loss which is a big buzz word in dermatology. It’s something that we want to keep a certain amount of moisture within the epidermis.

    We don’t want to make it completely dry and we don’t want to make it over-wetted either. So we want to take advantage of these vehicles to try to help heal the skin, in addition to driving the medication within, to the epidermis. And really a vehicle can make or break a formulation.

    Think about vehicles that are used in a brand name formula versus a generic formula. There is a difference. And you will see when you are in practice. That is the case. So what vehicles do we have out there? Well, the vehicle is what surrounds the active ingredient. And again – it does play a role. It doesn’t have any – it doesn’t actually change the active ingredient. But it is an important part. So an ideal vehicle for most of our patients is something that doesn’t smell, it’s not greasy, it’s easy to apply, it doesn’t irritate, it’s inexpensive, it’s cosmetic meaning it feels elegant when it goes on and it doesn’t leave a residue. Think about urea 40% that always leaves a white, powdery residue both that’s the nature of the – both the vehicle on the top for that.

    So what vehicles do we have? We have powders, gels, lotions, creams, foams, sprays, tape, emulsions, solutions, lacquers, topical suspensions and pastes. So we have a lot of different things to choose from and again it can get a little bit overwhelming at times.

    But vehicles do matter especially when you’re choosing again a proper topical medication for an inflammatory skin condition.

    So that said, an ointment is the most potent of all of these vehicles because it causes occlusion. So when it causes occlusion that kind of keeps that active ingredient on the surface of the skin and kind of creates this film on top of it and that increases the potency of it. So that’s why an ointment is often what people choose to use on the bottom of the foot. A cream is a little bit lesser in potency as you can imagine and a lotion would be the most diluted, right, a lotion is a little bit – has a little bit more of a higher water content than an ointment does.

    So traditional thinking is that, ointments are the best that we need to get the best penetration and efficacy. But actually the reality is, is that now that we have sprays and tapes and foams, things are changing.

    [0:05:00]

    So we don’t always have to use these greasy ointments to have the best efficacy for our patients.

    So ultimately what does a vehicle do? What do these, you know, tapes, foams, sprays, et cetera et cetera do? Well, they help basically create a concentration gradient. They have the active drug move out of it and allow that basically go on to the epidermis. Did you know that your epidermis is the largest drug metabolizing organ that you have? You always think about the liver? But this epidermis is actually your largest drug metabolizing organ.

    The enzymes are ready there to take care of whatever active ingredient is there and not only is your epidermis that large drug metabolizing organ but it’s also a barrier. So this vehicles have to overcome the epidermal barrier in order to get that active ingredient within. And you know, why is that important?

    Well, topical medications are able to get the medication exactly where you have your inflamed situation, or whatever situation you’re treating, as well as have little to no systemic effects. So it’s important that we have something that’s going to drive the medication into the epidermis, but also not have a terrible effect elsewhere.

    So the thing is, the vehicle itself can have a lot of good benefits. So the vehicle not only allows the active ingredient to move out of it and go into the epidermis where it can be taken up and metabolized by the skin and get to where it needs to be. But the vehicle itself can have moisturizing properties which we can take advantage of.

    The vehicle can also just help to create a nice film on the skin as well that feels elegant and better than what the patient started with.

    So what does this mean for us? Well, we have to take a couple of things to consideration when we’re choosing an appropriate topical vehicle. Number one, anatomy. Now on the foot, we have the interesting advantage of having multiple different kinds of services available. Think about the toes, we can have hairy toes. I always have patients who look like they could be hobbits and you could braid their digital hair.

    And then you have the plantar aspect of the foot which is completely hairless. So when you’re choosing something, you have to think about – okay is this going to be used just on the bottom? Or on the top? Is this going to be used in both places?

    So for instance, an ointment would be terrible to use in a hair bearing situation. It just kind of gets stuck in the hair. So for instance, if any of you have ever had any scalp issues, an ointment would not be the right thing to choose. You need something that’s a little bit easier to spread. Or something that’s just a little bit easier to apply, like a spray. So an ointment would not be the right thing to choose for a hair bearing area.

    What if you have a large surface areas like a lower leg? So for instance, you have a patient who just has the whole below the knee area that’s affected. Well, choosing an ointment wouldn’t be very spreadable. Sometimes, creams can be kind of heavy. So you’d want to use a lotion, a solution, a spray or even a foam that’s a little bit more spreadable and easier for the patient to use. Because you know when something is going to get hung up on the anatomy.

    What about the severity of the skin that you’re using? Now, I treat a lot of pyoderma gangrenosum. In fact, I don’t think I ever get any regular diabetic foot wounds, that all goes to my co-workers at Temple. But I love PGs. You could give me them all day long.

    The biggest thing I see is people try to use topical steroids within a wound for PG, for pyoderma gangrenosum. It’s an inflammatory based skin condition so ergo, you’d think, it makes sense. It doesn’t penetrate well through that kind of barrier. So using a topical steroid within the wound, not really going to work You can use it at periwound, but on the wound, I wouldn’t recommend it. So certainly, skin that’s inflamed is going to have a different sort of permeability than skin that’s intact. So we have to think about that as well.

    What about a wet lesion versus a dry lesion? Think about interdigital maceration. And I’m going to get into that a little bit further. But, you know, again, do we want to use that’s going to dry it or wet it or what do we want to do? What about patient occupation, my patients who come in who wear steel-toed boots all day? Do I really want to give them an ointment, something that’s going to be difficult to dry and put their socks and shoes on so that they can get about their day? So again, knowledge, ability and even ability to reach. There has been many times I’ve chosen sprays because my patients are morbidly obese and they’re unable to bend over and apply any medication. Or perhaps they have some sort of back issue, they’ve had their back, you know, fused and they’re unable to have anyone – themselves or someone else to apply a topical medication. So something that’s going to be easy to use is also something to consider. So patient perception and patient knowledge are really important when it comes to this.

    So when do we choose which one? Well, again, anything that’s plantar, whether it’s palmar or plantar, needs something that has a little bit better efficacy and potency.

    [10:00]

    So an ointment is ideal, however, again, not everybody wants something that’s greasy and is going to take a long time to dry. I give my patients the option. And a lot of times, my female patients in Philly who love cocoa butter. Those women love cocoa butter. I’ll say, would you like something greasy or would you like something that’s a little bit more creamy or liquidy. And they’re like, “grease, Doc, give me the grease.”

    But my male patients consistently will say, “I don’t want anything greasy. Give me something that’s going to dry.” So, ultimately, if you ask any dermatologist that’s out there that treats anything on the foot they’ll say, “You have got to go with an ointment. But the reality is is we have other things to choose from so I’ll talk about that in a few minutes. So foams and sprays are what I end up choosing a lot for my male patients or for my patients who don’t want something greasy on their foot.

    Again, for the lower leg, you certainly could use a lotion, but sprays are really easy to use because, again, if the patients can’t bend over and rub things in, a spray is easy to do.

    What about macerated interdigital spaces? Now I was taught the concept that you should – if it’s wet, you should dry it, right? Well, the reality is is that the original gels that came out were high in ethanol content. Ethanol is very irritating, right? It evaporates, it’s very irritating. The new gels that have come out are more water-based gels or hydrogels. So, for instance, the Naftin 2% gel that came out a few years ago, that’s a lot less irritating than the Naftifine 1% gel that was originally on the market.

    However, my paradigm shift changed regarding this because when I started to do clinical trials, and I’ve done a lot of clinical trials in my career, especially with tinea pedis and onychomycosis, we were using creams in between the toes, and that just – it went against everything that I was taught. However, when I was seeing patients change and recover from whatever malady that they have in between their toes, with a cream, it changed my mind. So certainly, it means that patients can’t glob on cream in between in between their toes. That can create a mess as well. But a sparing amount certainly is – can be appropriate for certain cases.

    For moccasin tinea, we can use a cream, emollient, emulsion, even a foam – there’s a foam out there, there’s econazole foam that you can use.

    Inflamed skin is, again, has increased absorption because those channels are even more open than what you would imagine. So you need to use a little bit of a less potent vehicle. You don’t want to use an ointment on an area that’s extremely inflamed. That would be almost too much for the patient. So that’s where we would use more of a liquid cream or even a solution.

    So, again, we have male and female preferences, and that’s usually occupation-wise and what they wear with shoes all day. Again, women like creams. They like something that’s a little bit more moisturizing and sometimes, again, can greasy. But my male patients really want something that’s going to be dry, easy to use and easy to put on their shoes.

    We also see things with age. My older patients prefer something that’s a little bit greasier, heavier, creamy. But my younger patients want something that’s going to be easy to use. So, again, a foam, a spray, even some lotions are what is preferable to them than anything else. So, ultimately, it’s about which lead to the best patient compliance. What am I going to choose that’s going to help this patient use that they’re actually going to use it? I will say, if I give somebody something to use twice today, they’ll use it once a day. If I give them something to use once a day, they’ll use it three times a week. So I have to think about what’s going to give me the most bang from my buck when I prescribe the medication.

    So in this case which vehicle would you choose? This is a patient who is allergic to propilenglicol. Propilenglicol is an enhancer that we see in these topical medications. What that means is it basically opens up the channels within the skin, because the skin is a barrier, and allows the active medication to go through. However, it can be extremely irritating and people can develop a contact dermatitis to it as this patient did.

    So would you use an ointment on this patient? No. Would you want to use a foam? You could. What I chose for this patient was a lotion. Again, easy to spread, something that she felt would feel better on her legs. Again, I don’t want to use something that’s so overly potent on a very inflamed open tissue. So, again, I used a lotion on this particular female patient.

    Then just, in general, with treating inflammatory conditions, topical steroids are the gold standard. If you have psoriasis in front of you, please don’t use an oral steroid. That is something that can precipitate, once the patient goes off of it, can precipitate other types of psoriasis, namely pustular and even erythrodermic. If we precipitate another type of psoriasis, namely erythrodermic, that means that they probably have to be admitted to the hospital and you’ve done more harm than good. So if you don’t know what it is, biopsy it.

    [0:15:00]

    Because, please, don’t give those patients oral steroids or even Medrol Dosepaks. That’s one of the Vlahovic commandments of dermatology.

    And you might say, “Well, I’ve given Medrol Dosepaks all the time and it doesn’t really seem to do anything.” Yes. But those patents come back, they’re miserable, they have a rebound and you haven't solved the problem. Medrol Dosepaks are too low and too short of a dose to really change anything. So please, if you’re going to give – if a patient has, say, eczema, you can do Prednisone taper. Please don’t do Medrol Dosepaks. I see it all the time. I see where people have gone wrong.

    Please don’t use a combination of a steroid and antifungal i.e. Lotrisone. Why is that? Because what happens with that is that, number one, you’re not treating what’s there. The only thing Lotrisone is absolutely appropriate for is a yeast infection. So if you have candida, that’s what Lotrisone is indicated for.

    If you say to me, “You know what, I'm not really sure if it’s fungus, I'm not really sure if it’s eczema or psoriasis, I can't lose. I'm going to give them both.” That is not how we practice medicine. That would be saying, “Well, I'm not really sure if you’ve got ejection fraction issues. I'm not really sure if you got blood pressure issues, so I'm just going to give you both medications.” You don’t want a doctor to do that. You want someone who knows exactly what you are dealing with and give you that appropriate medication.

    So, to me, when someone dispenses something like Lotrisone, number one, you’re not realizing that betamethasone is a class 1 topical steroid which can cause a lot of skin issues, a lot of side effects. That product should only be used no longer than two weeks consistently because after that we start having non-reversible skin thinning. And also, when you use a steroid on top of a fungal infection, you can cause something called tinea incognito. I always liken it – I'm not someone who can't eat seafood but I liken it to if you were to boil a lobster in a pot of water, right? That lobster, just like you put that lid on and it just wants to like jump out and like get out of that pot. When you remove that lid too soon, that lobster might just like kind of scare you and get over the side, right? That’s what’s happening here. You remove that steroid from that fungal infection, it goes crazy. It boils over. You don’t want to do that. So if you don’t know what it is, biopsy, refer out to someone who can treat it.

    So the thing is we want to identify – is it fungal, bacterial or an inflammatory skin condition? Treat it appropriately with the correct topical medication if that is warranted. What stage is it if it’s an inflammatory skin condition? Is it acute? Is it red and boiling over with blisters? Is it sub-acute where maybe it’s just a little bit red? Or is it chronic where we see like cornification and scale? Use the appropriate level for steroid for the amount of inflammation that patient has.

    Are there other medical factors that are going on that we have to consider with these patients? And ultimately, maybe topicals aren’t enough. Do we have to use something that’s systemic therapy? And again, if you don’t know what it is, biopsy it.

    So again, first line of defense for an inflammatory skin condition is a topical steroid. The class 1 topical steroids which are listed at the bottom of the slide are what’s appropriate to use for someone who says, “You know what, doc? I can’t sleep at night. I find blood on my sheets because I’m scratching my feet. You know, I don’t have any comfort whatsoever.” Those are the products I will use consistently twice a day for two weeks and then I titrate them down.

    One of the most important things we can add to this regimen is a barrier repair cream. So a good moisturizer, it doesn’t matter what you use, whether it’s over the counter or prescription and there’s lots and lots of great products that are out there that patients can easily find in the skin care aisle, should be also used to help, again, reduce that trans-epidermal water loss so that the skin can repair itself.

    So just to bring this home, you have a patient who has a really inflamed skin condition. You say, “All right, I think I want to give you a class 1 steroid.” But it’s the bottom of the foot and the patient doesn’t want something that’s greasy. They don’t want an ointment. So again, if you went to any dermatologist, they would say, “Give him a clobetasol ointment.” Well again, that’s not appropriate for every patient that we’re dealing with. We have choices.

    If you look under where it says class 1 super potent, most of those are clobetasols. But look at the choices that you have. You have a lotion, a spray, a cream, a solution, a foam. So you don’t have to pick an ointment every time.

    Again, for the plantar aspect of the foot, you could say, “You know what? A foam would be appropriate for you. You’ll still have the success that I want you to have but it’ll be easier for you to use.

    [0:20:00]

    And you know what? If it’s easier for you to use, you’ll actually use it. I’ll increase your compliance and also I’ll do my job in helping you to get better.

    Now, as you can see with betamethasone, which is another class 1 that I use quite a lot, the change in vehicle can also mean a change in the potency of it. So for instance, the class 1 diprolene ointment, gel and lotion. But that same product as a cream changes it to a little bit less potency. And changing it to a spray decreases its potency as well. So it’s important to just think about this when we’re again considering what medication we want to give someone. So obviously, for betamethasone an ointment, gel or lotion is going to be what’s going to give them the most potency, but the cream or the spray in that case is going to change its potency.

    So here’s for instance, this is a patient who came to me and said, “You know what, doc, I went to Temple emergency room. They basically said I had fungus.” And I said, “No, you have psoriasis, my friend.” He said, “If there’s anything you could give, you know, so I can continue working, what would you give me?” And I gave him clobetasol spray.

    The first picture that you see where it’s very inflamed and scaly, that’s patient at baseline when they came to see me. The middle picture is two weeks and the picture after that is four weeks. So again, just using that class 1 steroid for that long created a change for that patient but also allowed him to actually use the medication. If I would have given him, again, a different vehicle, that would’ve made him not want to use that product on a daily basis.

    So remember to tell our patients that too much is actually not good. We always think, “Well, the more neosporin we put on a loon, the better it’s going to heal.” That’s not true with dermatology. It’s a metered dose. It’s a fingertip dose. So it goes from crease of your index finger to the tip of your index finger. That’s one fingertip unit, and one fingertip unit goes on the bottom of the foot and one fingertip unit goes on the dorsum of the foot.

    So how are the ways that we can reduce atrophy for these patients? Well, if we give them a topical steroid, we can give them other medications to help reduce some of the side effects that we’ll see, namely like ammonium lactate. You can give that to a patient in addition to the topical steroid that you’re giving. And you can use them together or even have them mix it on their hand. And again, ultimately decrease some of the side effects that we see with these products.

    Calcipotriene is something that I use as a first line of defense for psoriasis all the time. And you can see the vehicles can make skin irritated. So of course an ointment, which is the most potent vehicle, actually had the most skin irritation versus the foam version of calcipotriene had the least skin irritation along with a solution. So not only just choosing the right vehicle for the right anatomical area and for the patient preference but we have to think about what’s actually going to be the best for them, because sometimes the medications we prescribe can actually make patients irritated as well.

    So just with dermatophyte infections along with the other inflammatory skin conditions we see, we have to think about what’s going to be best for that patient to use. So for instance, moccasin tinea which you see the plantar aspect of the foot versus a super infected tinea, certainly I’m going to change my game. Patients aren’t cookie cutter. They don’t get the same thing from me every time. I would prefer more of a spray in the case of the super infected tinea because, again, the patient may not be able to bend over and apply something individually to each inter-digital space.

    Now, I’m sorry that I’m going over a little bit but I just want to go through with nails a little bit. Not only do we have to think about vehicles with topical on the skin, we have to think about it with nails as well. And there’s a fine amazing science that goes through with nails as well.

    It’s not just about choosing anything to have something go on the nail. It’s about what’s going to enhance nail hydration, because of the more hydrated a nail is the more the medication can pass through. The size, the shape, the molecular weight, that all plays a part in the formulations that we use on the nails, not only just are we using something on the nail.

    So for instance, they looked at [Indecipherable] [0:24:21] for a year so which is hydrophilic, which we want something that’s water-loving in the nail versus tolnaftate, which is lipophilic. There’s a very little lipid in the nail plate. Tolnaftate didn’t even penetrate through the nail plate. They stopped studying it.

    So any of you who used tolnaftate on the topical on the aspect of the nail, you might see changes that you think you’re seeing, but in reality that’s too big of a molecular weight and it’s lipophilic. It’s not getting through the nail plate.

    So with efinaconazole 10% solution, it has a lower affinity to keratins. It’s not getting stuck within the nail plate, and it’s molecular weight is such that it can get through the nail plate as well.

    [0:25:00]

    Captopril is actually the smallest molecule that’s ever been approved by the FDA. It has the tiniest molecular weight and it has aqueous solubility so it’s able to get through that hydrated nail plate that’s created when we have the vehicle driving it through.

    And that’s it for me. I appreciate your attention, and if you have any questions, I’d be happy to entertain them. Thanks.


    TAPE ENDS - [25:27]