Pharm Chapter 56: Dermatologic Drugs

Anatomy, Physiology, and Pathophysiology Overview

-The skin is the largest organ of the body. It covers the body and serves several functions, including protection, sensation, temperature regulation, excretion, absorption, and metabolism. It acts as a protective barrier for the internal organs. -The skin is made up of two layers: (1) the dermis and (2) the epidermis. The outer skin layer, or epidermis, is itself composed of four layers. From the outermost to innermost, these are: (1) stratum corneum, (2) stratum lucidum, (3) stratum granulosum, and (4) stratum germinativum. -Traversing the dermis is a rich supply of blood vessels, nerves, lymphatic tissue, elastic tissue, and connective tissue, which provide extra support and nourishment to the skin. Also contained in the dermis are the exocrine glands—the eccrine, apocrine, and sebaceous glands—and the hair follicles. -A dermatosis is any abnormal skin condition. Dermatoses include a variety of types of dermatitis (skin in ammation). Among these are conditions such as atopic dermatitis, eczema, and psoriasis. In addition, there are also a variety of skin cancers, including basal cell carcinoma, squamous cell carcinoma, and melanoma.

Antimicrobials

Topical antimicrobials are antibacterial, antifungal, and antiviral drugs that are applied topically. Although they have many of the same properties as the systemic forms, there are differences in terms of their absorption, distribution, toxicities, and adverse effects

Isotretinoin (Amnesteem) and tretinoin (Retin-A) are common dermatologic drugs used to treat which condition? a. Acne vulgaris b. Keloid scarring c. Fungal infections d. Male pattern baldness

a. Acne vulgaris Isotretinoin and tretinoin are effective topical treatments for acne vulgaris. Isotretinoin inhibits sebaceous gland activity, and tretinoin stimulates the turnover of epidermal cells, resulting in skin peeling.

A patient is prescribed bacitracin topical ointment. What does the nurse suspect as the possible diagnosis based on the medication prescribed? a. Fungal infection b. Bacterial infection c. Parasitic infection d. Viral infection

b. Bacterial infection Bacitracin is a polypeptide antibiotic that is applied topically for the treatment or prevention of local skin infections caused by susceptible aerobic and anaerobic gram-positive organisms such as staphylococci, streptococci, anaerobic cocci, corynebacteria, and clostridia.

The nurse is discussing with a client over-the-counter and prescription topical medications available for treatment of acne. Which drugs are used in the treatment of acne? (Select all that apply.) a. Isotretinoin (Claravis) b. Clindamycin (Cleocin) c. Benzoyl peroxide (Benoxyl) d. Vitamin A acid (Ascor L 500) e. Norethindrone and ethinyl estradiol

b. Clindamycin (Cleocin) c. Benzoyl peroxide (Benoxyl) d. Vitamin A acid (Ascor L 500) Benzoyl peroxide, clindamycin, and vitamin A acid are available in topical treatment options for acne. Isotrentinoin is only an oral option. Acne vulgaris is an off-label use for the oral contraceptive norethindrone and ethinyl estrdiol (Ortho-Novum).

The nurse will anticipate application of which medication to treat a client diagnosed with impetigo? a. Retinoic acid (Renova) b. Mupirocin (Bactroban) c. Isotretinoin (Amnesteem) d. Benzoyl peroxide (Benoxyl)

b. Mupirocin (Bactroban) Impetigo is a skin disorder caused by bacteria and is treated with a topical antibacterial agent, mupirocin.

A client has been prescribed clotrimazole (Lotrimin, Mycelex-G) for the treatment of jock itch. To document this diagnosis in the client's medical record, the nurse should use which fungal infection name? a. Tinea pedis b. Tinea cruris c. Tinea capitis d. Tinea corporis

b. Tinea cruris Infections caused by dermatophytes are called tinea, or ringworm, infections. Tinea infections are identified by the body location where they occur: tinea pedis (foot), tinea cruris (groin), tinea corporis (body), and tinea capitis (scalp). Tinea infections of the foot are also known as athlete's foot and those of the groin as jock itch.

A female client of childbearing age is prescribed isotretinoin (Amnesteem) for the treatment of severe recalcitrant cystic acne. Which information is MOST important for the nurse to include in the education of the client? a. The drug is supplied in oral and buccal forms. b. The drug is used in treatment of severe acne. c. Use at least two forms of contraception while taking this medication. d. Health care providers who prescribe this medication must be certified.

c. Use at least two forms of contraception while taking this medication. The most important and mandatory teaching by the U.S. Food and Drug Administration is the requirement to use at least two different reliable forms of contraceptive methods during therapy with isotretinoin and for 1 month after completion of therapy.

A client who is prescribed the drug miconazole (Monistat), a topical antifungal, has MOST likely been diagnosed with which condition? a. Pruritus b. Eczema c. Folliculitis d. Candidiasis

d. Candidiasis Miconazole is used in the treatment of candidiasis, which is commonly known as a yeast infection.

When planning care for a burn client, the nurse would anticipate applying which topical medication? a. Lindane (Kwell) b. Minoxidil (Rogaine) c. Erythromycin (E-Mycin) d. Silver sulfadiazine (Sulfadine)

d. Silver sulfadiazine (Sulfadine) Silver sulfadiazine is a topical antiinfective drug used to treat and prevent infection in second- and third-degree burns.

Antiviral Drugs

• A common topical viral infection is herpes simplex virus types 1 and 2. • Topical antivirals are now used less frequently than before because systemic antiviral drug therapy has generally been shown to be superior for controlling such viral skin conditions. • Viral infections are very difficult to treat because they live in the body's own healthy cells and use their cell mechanisms to reproduce. • The only topical antiviral drugs currently available to treat such viral infections are acyclovir (Zovirax) and penciclovir (Denavir). • The most common adverse effects are stinging, itching, and rash.

Antiacne Drugs

• Acne vulgaris is the most common skin infection. Likely caus- ative factors include heredity, stress, drug reactions, hormones, and bacterial infections. Common bacterial causes include Staphylococcus species and Propionibacterium acnes. • Some of the most commonly used antiacne drugs are benzoyl peroxide, clindamycin, erythromycin, tetracycline, isotretinoin, and the vitamin A acid known as retinoic acid. Other drugs are used, such as systemic formulations of minocycline, doxycycline, and tetracycline. • Retinoids are used in the treatment of stable plaque psoriasis and mild to moderately severe facial acne.

General Antibacterial Drugs

• Bacterial skin disorders include folliculitis, impetigo, furuncles, carbuncles, and cellulitis. The bacteria responsible are most commonly Streptococcus pyogenes and Staphylococcus aureus. Dermatologic antibacterial drugs, such as bacitracin, polymyxin, and neomycin, are used to treat or prevent these skin infections. Unfortunately, due to the high incidence of infection with methicillin-resistant S. aureus (MRSA), mupirocin is now also commonly used.

Pharmacology Overview

• Drugs administered directly to the skin are called topical dermatologic drugs and are available in a variety of formula- tions, with each having specific characteristics that make them beneficial for certain uses. • Systemically administered drugs (transdermal) are also used to treat several skin disorders. • Some of the more common therapeutic categories of dermatologic drugs include the following: antibacterial, antifungal, anti-inflammatory, antineoplastic, antipruritic, antiviral, keratolytic, and topical vasodilators. Other categories include dermatologic drugs used as emollients, debriding, local anesthetics, and for treating burns.

Miscellaneous Dermatologic Drugs

• Ectoparasites are insects that live on the outer surface of the body, and the drugs that are used to kill them are called ectoparasiticidal drugs. Lice are transmitted from person to person by close contact with infested individuals, clothing, combs, or towels. • A parasitic infestation on the skin with lice is called pediculosis. • Common findings in infested persons include itching; eggs of the lice attached to hair shafts (called nits); lice on the skin or clothes; and, in the case of pubic lice, sky blue macules (discolored skin patches) on the inner thighs or lower abdomen. Pediculoses are treated with a class of drugs called pediculicides. A second common parasitic skin infection known as scabies is that caused by the itch mite Sarcoptes scabiei. Scabies is transmitted from person to person by close contact, such as by sleeping next to an infested person. • Treatment of these parasites begins with identification of the source of infestation to prevent reinfestation. The clothing and personal articles of the infested person are decontaminated. • In addition to lindane, malathion (Ovide) and crotamiton (Eurax) are also ectoparasiticidal drugs. • The newest drugs approved for lice treatment are benzyl alcohol 5% (Ulesfia), which works by suffocating the lice, and spinosad (Natroba). Natroba is indicated for children 4 years of age and older and offers the benefit of not requiring nit combing as do the other treatments. • Minoxidil (Rogaine) is a vasodilating drug that is administered systemically to control hypertension. Topically it has the same vasodilating effect, but when used in this way it is applied to the scalp to stimulate hair growth. • Minoxidil can be used by both men and women who experience baldness or hair thinning. • Systemic absorption of topically applied minoxidil may occur with possible adverse effects, including tachycardia, fluid retention, and weight gain. Local effects may include skin irritation, and the drug is not to be applied to skin that is already irritated or used concurrently with other topical medications applied to the same site. • The systemically administered drug finasteride (Proscar, 5 mg) is used to treat benign prostatic hyperplasia. A lower-strength version known as Propecia (1 mg) is also used to treat male pattern alopecia. Finasteride is classified as a pregnancy category X drug, and women are not to handle this drug without gloves or crush this drug, thereby making it airborne. • Sunscreens are topical products used to protect the skin from damage caused by the ultraviolet (UV) radiation of sunlight. Most sunscreens come in lotion, cream, gel form, or lip balm. • Sunscreens are given a sun protection factor (SPF) rating, which is a number ranging from 2 to 50 (and even higher in some newer products) in order of increasing potency of UV protection. In 2011, the FDA stated that only those with SPF of 15 or greater may state they reduce the risk of skin cancer and early skin aging. • Skin cancer is the most common form of cancer. There are two types of nonmelanoma skin cancer: (1) basal cell carcinoma and (2) squamous cell carcinoma. Basal cell carcinoma is the most common and is rarely fatal, but it can be highly disfiguring. Squamous cell carcinoma, on the other hand, can be fatal, with 2500 deaths reported annually. The most aggressive skin cancer is melanoma and accounts for only 3% of all skin cancers but is responsible for 75% of deaths associated with skin cancer. The most common cause of skin cancer is exposure to the sun and tanning beds. Early detection and prevention are of the utmost importance. • Various premalignant skin lesions and basal cell carcinomas may be treated with the topically applied antineoplastic drug fluorouracil (Efudex). It is also used topically in the treatment of solar or actinic keratosis and superficial basal cell carcinomas of the skin—often in addition to local surgical excision. • More aggressive skin cancers (squamous cell carcinoma and malignant melanoma) are not treated with fluorouracil but are usually treated with more aggressive interventions, such as surgery, radiation therapy, and/or systemic chemotherapy. • The adverse effects associated with the topical use of this antineoplastic drug are generally limited to local inflammatory reactions such as dermatitis, stomatitis, and photosensitivity. More serious effects include swelling, scaling, pain, pruritus, burning, soreness, tenderness, suppuration, scarring, and hyperpigmentation. • Another topical drug also used for the treatment of actinic keratoses and basal cell carcinomas is the immunomodulator imiquimod. • Although superficial skin wounds usually require minimal interventions, deeper skin wounds often require more definitive care for optimal healing. Vitamin C and zinc have been shown to improve wound healing when they are given orally. • Tar derivatives have antiseptic, antibacterial, and antiseborrheic properties. • Isopropyl alcohol (70%) is most commonly used to prepare the skin before minor procedures such as drawing blood or giving injections. • Other drugs that are used to prepare the skin include povidone-iodine (Betadine), chlorhexidine (Hibiclens), and benzalkonium chloride (Zephiran). • Benzalkonium chloride is a surface-active drug that works by denaturing the microorganism or essentially destroying its protein. • Chlorhexidine acts by disrupting bacterial membranes and inhibiting cell wall synthesis. It is used primarily as a surgical scrub or hand washing agent by health care professionals. • Povidone-iodine is an antiseptic that kills bacteria, fungi, and viruses. It is used for the prevention or treatment of topical infections associated with surgery, burns, and minor cuts and scrapes, and for relief of minor vaginal infections. It is the most widely used antiseptic, but patients should be screened for iodine or shellfish allergies before using it.

Antipsoriatic Drugs

• Psoriasis is a common skin condition in which areas of the skin become thick, reddened, and covered with silvery scales. Psoriasis is actually a result of a disordered immune system, although it is generally referred to as a skin condition. It is believed to involve polygenic (multigene) inheritance. Psoriasis has fluctuating patterns of recurrence and remission. • Treatment begins with a topical corticosteroid for mild-to- moderate cases. If not successful, topical antipsoriatic drugs are used. • In addition to these topical drugs, there are also newer systemically administered antipsoriatic drugs. Those given by injection include the biologic response modifier etanercept (Enbrel), the antineoplastic drug methotrexate (antipsoriatic properties), and the interleukin 12 inhibitor ustekinumab (Stelara). • Those given by injection include etanercept (Enbrel), which is given subcutaneously, and alefacept (Amevive), which is given intramuscularly. • The newest injectable drug, ustekinumab (Stelara), is an interleukin 12 inhibitor for plaque psoriasis. It is given subcutaneously. Patients must receive a patient medication guide approved by the U.S. Food and Drug Administration (FDA). The most serious side effect is increased risk of infection.

Topical Anesthetics

• Topical anesthetics are drugs used to numb the skin by inhibiting the conduction of nerve impulses from sensory nerves, thereby reducing or eliminating the pain or pruritus associated with insect bites, sunburn, and allergic reactions to plants such as poison ivy, and other skin disorders. They are also used to numb the skin before a painful injection (e.g., insertion of an intravenous line in a pediatric patient). They are available as ointments, creams, sprays, liquids, and jellies. • A lidocaine/prilocaine combination drug (EMLA [eutectic mixture of local anesthetics]) and lidocaine alone (Ela-Max) are topical anesthetic drugs that are used frequently, especially in pediatric patients. EMLA is applied 1 hour before the procedure, whereas Ela-Max is effective within 30 minutes.

Nursing Process

• Topical antibacterials are associated with a wide range of reactions because of the generalized sensitivity of patients to antibiotics, even when in a different dosage form; therefore, if a patient is allergic to a systemic antibacterial, he or she will also be allergic to topical dosage forms. • The skin of very young and elderly patients is more fragile and permeable to certain topical dermatologic preparations. This could also lead to higher risk for systemic absorption from the skin. • Before any topical medication is applied, cleanse the affected area of any debris, drainage, and/or residual medication, taking care to follow any specific directions such as removing water-or alcohol-based topical preparations with soap and water. • Most topical dermatologic drugs do not require use of a dressing once the medication is applied. • Medicated areas may also need to be protected from exposure to air or sunlight. • Therapeutic responses to the various dermatologic preparations include improved condition of the skin and healing of lesions or wounds; a decrease in the size of lesions with eventual resolution; and a decrease in swelling, redness, weeping, itching, and burning of the area. • Adverse effects include increased severity of symptoms—for example, increased redness, swelling, pain, and drainage; fever; or any other unusual problems at the affected area. Adverse effects may range from slight irritation of the site where the topical drug has been applied to an allergic reaction to toxic systemic effects. • Topical anesthetics are used therapeutically to numb the skin. Indications for topical anesthetics include insect bites, sunburn, poison ivy, and prevention of pain from injections. • Corticosteroids are some of the most widely used topical drugs and are indicated for relief of topical inflammatory and pruritic disorders. Bene cial effects of corticosteroids include anti-inflammatory, antipruritic, and vasoconstrictor actions. Some of the negative effects of potent corticosteroid use or prolonged use of weaker corticosteroids include dermal atrophy and adrenal insufficiency. • Adverse and toxic reactions to dermatologic drugs can and do occur; therefore, administer these drugs cautiously, and follow the prescriber's orders and manufacturer's guidelines. This is critical to ensure safe and effective treatment. • Patient education about the medication, its administration, and its effectiveness are important to ensure compliance with the treatment regimen.

Topical Antipruritics and Anti-inflammatories

• Topical antipruritic (anti-itching) drugs contain antihistamines or corticosteroids. Many exert a combined anesthetic and antipruritic action when applied topically. • New recommendations for topical antihistamines state that these drugs are not to be used to treat the following conditions because of systemic absorption and subsequent toxicity: chickenpox, widespread poison ivy lesions, and others involving large body surface areas. • The most commonly used topical anti-inflammatory drugs are the corticosteroids. • When topically administered corticosteroids are used, many of the undesirable systemic adverse effects associated with systemically administered corticosteroids are avoided. • The beneficial drug effects of topically administered corticosteroids are their anti-inflammatory, antipruritic, and vasoconstrictive actions. • Adverse effects of these drugs include skin reactions such as acne eruptions, allergic contact dermatitis, burning sensations, dryness, itching, skin fragility, hypopigmentation, purpura, hirsutism (usually facial), folliculitis, round and swollen face, alopecia (usually of the scalp), and the opportunistic overgrowth of bacteria, fungi, or viruses as a result of the immunosuppressive effects.

Antifungal Drugs

•A few fungi produce keratinolytic enzymes, which allow them to live on the skin. Topical fungal infections are primarily caused by Candida spp. (candidiasis), dermatophytes, and Malassezia furfur (tinea versicolor). These fungi are found in moist, warm environments, especially in dark areas such as the feet or groin. -Candidal infections are most commonly caused by Candida albicans, a yeast-like opportunistic fungus present in the normal flora of the mouth, vagina, and intestinal tract. Two significant factors that commonly predispose a person to a candidal infection are broad-spectrum antibiotic therapy, which promotes an overgrowth of nonsusceptible organisms in the natural body flora, and immunodeficiency disorders. -Dermatophytes are a group of three closely related genera consisting of Epidermophyton spp., Microsporum spp., and Trichophyton spp. that use the keratin found on the skin to feed their growth. They produce superficial mycotic (fungal) infections of keratinized tissue (hair, skin, and nails). Infections caused by dermatophytes are called tinea, or ringworm, infections. The name ringworm comes from the fact that the infection sometimes assumes a circular pattern at the site of infection. -Tinea infections are further identified by the body location where they occur: tinea pedis (foot), tinea cruris (groin), tinea corporis (body), and tinea capitis (scalp). Tinea infections of the foot are also known as athlete's foot and those of the groin as jock itch. • Antifungal therapy may be required for periods ranging from several weeks to as long as 1 year. Many topical antifungal drugs are available for treatment of both dermatophytic infections and those caused by yeast and yeast-like fungi. Systemically administered antifungal drugs are sometimes used to treat skin conditions as well. • Efinaconazole (Jublia) was the newest topical antifungal approved in 2014. It is indicated for toenail fungus. Patients using efinaconazole must avoid heat, nail polish, and pedicures. • The most commonly reported adverse effects of topical antifungals are local irritation, pruritus, a burning sensation, and scaling.