Download 0.59 Mb.
Jassin M. Jouria, MD
Dr. Jassin M. Jouria is a medical doctor, professor of academic medicine, and medical author. He graduated from Ross University School of Medicine and has completed his clinical clerkship training in various teaching hospitals throughout New York, including King’s County Hospital Center and Brookdale Medical Center, among others. Dr. Jouria has passed all USMLE medical board exams, and has served as a test prep tutor and instructor for Kaplan. He has developed several medical courses and curricula for a variety of educational institutions. Dr. Jouria has also served on multiple levels in the academic field including faculty member and Department Chair. Dr. Jouria continues to serves as a Subject Matter Expert for several continuing education organizations covering multiple basic medical sciences. He has also developed several continuing medical education courses covering various topics in clinical medicine. Recently, Dr. Jouria has been contracted by the University of Miami/Jackson Memorial Hospital’s Department of Surgery to develop an e-module training series for trauma patient management. Dr. Jouria is currently authoring an academic textbook on Human Anatomy & Physiology.
Skin diseases range in types, onset and severity in individuals. Healthcare providers need to be informed of the varied conditions and pharmacology treatments in order to provide comprehensive care. Dermatology treatment may be directed toward the treatment of an inflammatory process, co-morbid medical condition, or it may be cosmetic to achieve a patient desire outcome involving a change in physical appearance. The practice of dermatology is a blending of traditional and market factors, which health providers should be aware of when guiding patients in their health management and medication treatment choices.
Continuing Nursing Education Course Planners
William A. Cook, PhD, Director, Douglas Lawrence, MA, Webmaster,
Susan DePasquale, MSN, FPMHNP-BC, Lead Nurse Planner
This activity has been planned and implemented in accordance with the policies of NurseCe4Less.com and the continuing nursing education requirements of the American Nurses Credentialing Center's Commission on Accreditation for registered nurses. It is the policy of NurseCe4Less.com to ensure objectivity, transparency, and best practice in clinical education for all continuing nursing education (CNE) activities.
Continuing Education Credit Designation
This educational activity is credited for 5 hours. Nurses may only claim credit commensurate with the credit awarded for completion of this course activity.
Pharmacology content is 5 hours.
Statement of Learning Need
The skin is an important body organ to understand, especially while considering the many factors that influence percutaneous medication use and efficacy. Many factors ultimately affect therapeutic efficacy of dermatology pharmaceuticals. Knowledge of the different forms and properties of dermatology medication is essential to patient care outcomes; and, of the market influences on patient cost and compliance.
To provide nursing professionals with knowledge of dermatology pharmacology to support medication efficacy for varied skin conditions and to improve patient understanding and compliance with medication use.
Advanced Practice Registered Nurses and Registered Nurses
(Interdisciplinary Health Team Members, including Vocational Nurses and Medical Assistants may obtain a Certificate of Completion)
Course Author & Planning Team Conflict of Interest Disclosures
Jassin M. Jouria, MD, William S. Cook, PhD, Douglas Lawrence, MA,
Susan DePasquale, MSN, FPMHNP-BC – all have no disclosures
Acknowledgement of Commercial Support
There is no commercial support for this course.
Activity Review Information
Reviewed by Susan DePasquale, MSN, FPMHNP-BC
Release Date: 1/1/2016 Termination Date: 10/18/2018
Please take time to complete a self-assessment of knowledge, on page 4, sample questions before reading the article.
Opportunity to complete a self-assessment of knowledge learned will be provided at the end of the course.
1. _____________ is defined as the decrease in drug response due to the use of a drug over a prolonged period of time.
a) Tapering down
b) Rebound effect
d) Topical nonadherence
2. There are two fields in dermatology:
a) medical and cosmetic dermatology.
b) surgical and cosmetic dermatology.
c) dermatology and general medicine.
d) dermatology and surgery.
3. ____________ are at an increased risk of absorbing topical corticosteroids.
b) Individuals who are underweight
d) The elderly
4. True/False: Cosmetic dermatologists are required to fulfill residency requirements before they may offer cosmetic procedures.
5. Which of the following is a topical dermatologic treatment:
c) Anti-infective agents
In the course of a day, dermatologists see a wide variety of patients with concerns ranging from serious medical conditions like cancer to cosmetic issues that impact the patient's physical and emotional health. As with most other specialties, pharmacological agents can be a useful resource for treating dermatological concerns involving the hair, nails, and skin. There are a wide variety of pharmacological agents that can be utilized in treating dermatological issues, and they are typically delivered either topically or percutaneously. As with any medical treatment, the purpose of these pharmacological agents is to provide relief for the patient's issue with a minimal amount of pain and other side effects.
Medical And Cosmetic Dermatology
There are two fields in dermatology: medical dermatology and cosmetic dermatology. Dermatologists are physicians trained in the medical, surgical, and cosmetic care of the skin. To become a dermatologist, physicians must spend an additional year of internship in general medicine, and then another three years training in the specialty of dermatology after they complete medical school.1 This training includes medical, surgical, and cosmetic dermatology. Regardless of their career goals, all dermatologists receive training in the following specialties:2
Many dermatologists do not specialize in one area; instead, they choose to practice in all of these areas.
It is important to note that providers who do not receive training in cosmetic procedures during their residency may also offer cosmetic procedures. There are no residency requirements for cosmetic dermatologists. Even aestheticians are able to offer some basic cosmetic procedures.
When a dermatologist chooses to specialize in cosmetic dermatology, he or she will likely perform the following treatments:3
Dermatology Treatment: Topical Agents
Topical dermatologic treatments include varied options. These are listed below.4
Vehicles of Topical Therapies
Topical therapies can be delivered in various vehicles, which include:
The vehicle influences a therapy’s effectiveness and may cause adverse effects (i.e., contact or irritant dermatitis). Generally, aqueous and alcohol-based preparations are drying because the liquid evaporates are used in acute inflammatory conditions.5 Powders are also drying. Oil-based preparations are moisturizing and are preferred for chronic inflammation. Vehicle selection is guided by location of application, cosmetic effects, and convenience.6
Powders absorb moisture and decrease friction. Because they adhere poorly to the skin, their use is mainly limited to cosmetic and hygienic purposes. Generally, powders are used in the intertriginous areas and on the feet. The adverse effects of powders include: caking (especially if used on weeping skin), crusting, irritation, and granuloma formation.7 Furthermore, the user may inhale powders. Most powders contain zinc oxide for its antiseptic and covering properties, talc (primarily composed of magnesium silicate) for its lubricating and drying properties, and a stearate for improved adherence to the skin. Calamine is a popular skin-colored powder composed of 98% zinc oxide and 1% ferric oxide and acts as an astringent to relieve pruritus. Other drugs formulated as powders include some over-the-counter antifungals.8
A poultice, also referred to as a cataplasm, is a wet solid mass of particles, sometimes heated, that is applied to diseased skin. Historically, poultices contained meal, herbs, plants, and seeds. The modern poultice often consists of porous beads of dextranomer. Poultices are used as wound cleansers and absorptive agents in exudative lesions such as decubiti and leg ulcers.9
Ointments are semisolid preparations that spread easily. They are petrolatum-based vehicles, capable of providing occlusion, hydration, and lubrication. Drug potency is often increased from an ointment vehicle because of the ointment’s enhanced permeability. Ointment bases used in dermatology can be classified into five categories: (1) hydrocarbon bases, (2) absorption bases, (3) emulsions of water-in-oil, (4) emulsions of oil-in-water, and (5) water-soluble bases.
Dermatologists commonly refer to the hydrocarbon bases and absorption bases as ointments, and the water-in-oil or oil-in-water emulsion bases as creams. In pharmaceutical terms, all of these preparations are ointments and are specifically indicated for conditions affecting the glabrous skin (palms and soles) and lichenified areas.10
Absorption bases contain hydrophilic substances that allow for the absorption of water-soluble drugs. The hydrophilic (polar) compounds may include lanolin and its derivatives, cholesterol and its derivatives, and the partial esters of polyhydric alcohols such as sorbitan monostearate. These ointments are lubricating and hydrophilic, and they can form emulsions. They function well as emollients and protectants. They are greasy to apply but are easier to remove than the hydrocarbon bases. They do not contain water. Examples include anhydrous lanolin and hydrophilic petrolatum.11
Emulsions are two-phase systems involving one or more immiscible liquids dispersed in another, with the assistance of one or more emulsifying agents. A water-in-oil emulsion, by definition, contains less than 25% water, with oil being the dispersion medium. The two phases may separate unless shaken. The emulsifier (or surfactant) is soluble in both phases and surrounds the dispersed drops to prevent their coalescence. Examples of surfactants used include sodium lauryl sulfate, the quaternary ammonium compounds, Spans (sorbitan fatty acid esters), and Tweens (polyoxyethylene sorbitan fatty acid esters). Preservatives are frequently added to increase the emulsion’s shelf life. Water-in-oil emulsions are less greasy, spread easily on the skin, and provide a protective film of oil that remains on the skin as an emollient, while the slow evaporation of the water phase provides a cooling effect.7
An oil-in-water emulsion contains greater than 31% water. In fact, the aqueous phase may comprise up to 80% of the formulation. This type of formulation is the one most commonly chosen to deliver a dermatologic drug. Clinically, oil-in-water emulsions spread very easily, are water washable and less greasy, and are easily removed from the skin and clothing. Invariably, they contain preservatives, such as the parabens, to inhibit the growth of molds. Additionally, oil-in-water emulsions contain a humectant (an agent that draws moisture into the skin), such as glycerin, propylene glycol, or polyethylene glycol (PEG), to prevent the cream from drying out. The oil phase may contain either cetyl or stearyl alcohol (paraffin alcohols) to impart a stability and velvety smooth feel upon application to the skin. After application, the aqueous phase evaporates, leaving behind both a small hydrating layer of oil and a concentrated deposit of the drug.12
Water-soluble bases consist either primarily or completely of various PEGs. Depending on their molecular weight, PEGs are either liquid (PEG 400) or solid (PEG 4,000). These formulations are water soluble, will not decompose, and will not support the growth of mold, and therefore require no preservative additives. They are much less occlusive than water-in-oil emulsions, nonstaining, greaseless, and easily washed off of the skin. Without water, this ointment poorly delivers its coformulated drug. Therefore, it will be useful in scenarios where the practitioner desires a high surface concentration and low percutaneous absorption of the drug. For example, topical antifungal drugs and topical antibiotics (i.e., mupirocin) are formulated in this type of base.
Gels are made from water-soluble bases by formulating water, propylene glycol, and/or PEGs with a cellulose derivative or carbopol. A gel consists of organic macromolecules uniformly distributed in a lattice throughout the liquid. After application, the aqueous or alcoholic component evaporates, and the drug is deposited in a concentrated form. This provides a faster release of the drug independent of its water solubility. Gels are popular because of their clarity and ease of both application and removal. They are suitable for facial or hairy areas because after application little residue is left behind. Nevertheless, they lack any protective or emollient properties. If they contain high concentrations of alcohol or propylene glycol, they tend to be drying or cause stinging.
Gels require preservatives. Newer gel formulations may contain the humectant glycerin, the emollient dimethicone, or the viscoelastic polysaccharide hyaluronic acid, which can mitigate some of the associated irritation. Nonaqueous gels, with bases such as glycerol, may be used for poorly solubilized therapeutics such as 5-aminolevulonic acid. Microspheres, or microsponges, are formulated in an aqueous gel. Medication, in this case tretinoin, is combined into porous beads 10–25 μm in diameter. The beads are made up of methyl methacrylate and glycol dimethacrylate.13
Pastes are simply the incorporation of high concentrations of powders (up to 50%) into an ointment such as a hydrocarbon base or a water-in-oil emulsion. The powder must be insoluble in the ointment. Invariably, they are “stiffer” than the original ointment. The powders commonly used are zinc oxide, starch, calcium carbonate, and talc. Pastes function to localize the effect of a drug that may be staining or irritating (i.e., anthralin). They also function as impermeable barriers that serve as protectants or sunblock. Pastes are less greasy than ointments, more drying, and less occlusive.14,15
Liquids can be subdivided into solutions, suspensions, emulsions and foams. These are described below.
A solution involves the dissolution of two or more substances into homogenous clarity. The liquid vehicle may be aqueous, hydroalcoholic, or nonaqueous (alcohol, oils, or propylene glycol). An example of an aqueous solution is aluminum acetate or Burow solution. A hydroalcoholic solution with a concentration of alcohol of approximately 50% is called a tincture. A collodion is a nonaqueous solution of pyroxylin in a mixture with ether and ethanol, and is applied to the skin with a soft brush. Flexible collodions have added castor oil and camphor and are used, for example, to deliver 10% salicylic acid as a keratolytic agent.
Liniments are nonaqueous solutions of drugs in oil or alcoholic solutions of soap. The base of oil or soap facilitates application to the skin with rubbing or massage. Liniments can be used as counterirritants, astringents, antipruritics, emollients, and analgesics.16-18
A suspension, or lotion, is a two-phase system consisting of a finely divided, insoluble drug dispersed into a liquid in a concentration of up to 20%. Nonuniform dosing can result in the suspended particles coalescing and separating out of a homogeneous mixture, therefore shaking of the lotion before application may be required. Examples include calamine lotion, steroid lotions, and emollients containing urea or lactic acid. The applied lotion leaves the skin feeling cooler via evaporation of the aqueous component.
Lotions are easier to apply and allow for uniform coating of the affected area, and are often the favorite preparation in treating children. Lotions are more drying than ointments, and preparations with alcohol tend to sting eczematized or abraded skin. Additionally, lotions are suitable for application to large surface areas due to their ability to spread easily.19
Shake lotions are lotions to which a powder is added to increase the surface area of evaporation. As a result of the increased evaporation, the application of shake lotions effectively dries and cools wet and weeping skin. Generally, shake lotions consist of zinc oxide, talc, calamine, glycerol, alcohol, and water, to which specific drugs and stabilizers may be added. Shake lotions tend to develop sediment, and derive their name from the need to shake the preparation before each use to obtain a homogeneous suspension. In addition, after water has evaporated from the lotion, the powder component may clump together and become abrasive. Therefore, patients should be instructed to remove the residual particles before the reapplication of shake lotions.20
Foams are triphasic liquids composed of oil, organic solvents and water, which are kept under pressure in aluminum cans. Foams are formulated with a hydrocarbon propellant, either butane or propane. The foam lattice is formed when the valve is activated. Once in contact with the skin, the lattice breaks down, the alcohol evaporates within 30 seconds, and leaves minimal residue on the skin. The alcohol component of the foam is thought to act as a penetration enhancer, momentarily altering the barrier properties of the stratum corneum (outermost layer of the skin) and increasing drug delivery through the intercellular route.
Previous studies have demonstrated that foam vehicles are highly effective in delivering greater amount of active drug at an increased rate when compared to other vehicles that traditionally depend upon hydration of the intercellular spaces within the stratum corneum. Foams have not been associated with an increase in adverse events and compliance seems to be better with this formulation, especially for localized conditions affecting the scalp.3,21
Topical aerosols may be used to deliver drugs formulated as solutions, suspensions, emulsions, powders, and semisolids. Aerosols involve formulating the drug in a solution within a pure propellant. Usually, the propellant is a blend of nonpolar hydrocarbons. When applied to abraded or eczematized skin, aerosols lack the irritation of other formulations, especially when the quality of the skin makes direct application painful or difficult. Furthermore, aerosols dispense a drug as a thin layer with minimal waste, and the unused portion cannot be contaminated.
Aerosol foams, a relatively new vehicle for drug delivery, are commonly used to deliver corticosteroids such as betamethasone valerate and clobetasol propionate. The foam contains the drug within an emulsion formulated with a foaming agent (a surfactant), a solvent system (such as water and ethanol), and a propellant. On application, a foam lattice forms transiently until both the heat of the skin and the heat of rubbing the foam onto the skin break it down. Foams that are alcohol based leave very little residue within seconds of their application. Furthermore, a given corticosteroid formulated in a foam vehicle demonstrates comparable potency when compared with the same corticosteroid in other vehicles. Although aerosols allow for the ease of application (especially to hair-bearing areas) and high patient satisfaction, they suffer from the disadvantages of being expensive and potentially ecologically damaging.
A penetration enhancer is a compound that is able to promote drug transport through the skin barrier.
Skin hydration and interaction with the polar head group of the lipids are mechanisms for increasing penetration. Water, alcohols (mainly ethanol), sulphoxides (dimethylsulphoxide/DMSO), decylmethylsulphoxide/DCMS, azones (laurocapram), and urea are some of the most commonly used compounds. Urea is thought to act as a penetration enhancer due to its keratolytic properties and by increasing the water content in the stratum corneum. Other substances that may also act as chemical enhancers include propylene glycol, surfactants, fatty acids, and esters.
Vesicular systems are widely used in dermatologic and cosmetic fields to enhance drug transport into the skin through the transcellular and follicular pathways. Examples of vesicular systems include liposomes (phospholipid-based vesicles), niosomes (nonionic surfactant vesicles), proliposomes and proniosomes, which, respectively, are converted to liposomes and niosomes upon hydration.5,22,23
Physical methods such as the application of a small electric current (iontophoresis), ultrasound energy (phono- or sonophoresis) and the use of microneedles increase cutaneous drug penetration. Microdermoabrasion is the application of crystals (generally aluminum oxide) on the skin and the collection of such crystals and skin debris under vacuum suction. Microdermabrasion is a technique that enhances drug permeation and facilitates drug absorption by altering the architecture of the stratum corneum.24
Stabilizers are nontherapeutic ingredients and include the preservatives, antioxidants, and chelating agents. Preservatives protect the formulation from microbial growth. The ideal preservative is effective at a low concentration against a broad spectrum of organisms, nonsensitizing, odor free, color free, stable, and inexpensive. Unfortunately, the ideal preservative does not exist. The parabens are the most frequently added preservatives, and are active against molds, fungi, and yeasts, but less effective against bacteria. Alternative agents include the halogenated phenols, benzoic acid, sodium benzoate, formaldehyde, the formaldehyde-releasing agents, and previously, thimerosal. Most commonly used preservatives may act as contact sensitizers.25
Antioxidants or preservatives prevent the drug or vehicle from degrading via oxidation. Examples include butylated hydroxyanisole and butylated hydroxytoluene, used in oils and fats. Ascorbic acid, sulfites, and sulfur-containing amino acids are used in water-soluble phases. Chelating agents, such as sodium EDTA and citric acid, work synergistically with antioxidants by complexing heavy metals in aqueous phases.26
Thickening agents increase the viscosity of products or suspend ingredients in a formulation. Examples include bees-wax and carbomers. In addition to functioning as an ointment vehicle, petrolatum may be added to an emulsion to increase its viscosity. As in this example, an ingredient may have a therapeutic effect as well as acting as part of a vehicle.27